Package com.univocity.parsers.common

Class AbstractWriter<S extends CommonWriterSettings<?>>

    • Field Detail

      • writer

        private java.io.Writer writer

      • skipEmptyLines

        private final boolean skipEmptyLines

      • comment

        protected final char comment

      • isHeaderWritingEnabled

        private final boolean isHeaderWritingEnabled

      • outputRow

        private java.lang.Object[] outputRow

      • indexesToWrite

        private int[] indexesToWrite

      • lineSeparator

        private final char[] lineSeparator

      • recordCount

        protected long recordCount

      • nullValue

        protected final java.lang.String nullValue

      • emptyValue

        protected final java.lang.String emptyValue

      • partialLine

        private final java.lang.Object[] partialLine

      • partialLineIndex

        private int partialLineIndex

      • largestRowLength

        private int largestRowLength

      • writingHeaders

        protected boolean writingHeaders

      • headerTrimFlags

        protected boolean[] headerTrimFlags

      • expandRows

        protected boolean expandRows

      • usingSwitch

        private boolean usingSwitch

      • enableNewlineAfterRecord

        private boolean enableNewlineAfterRecord

      • usingNullOrEmptyValue

        protected boolean usingNullOrEmptyValue

      • whitespaceRangeStart

        protected final int whitespaceRangeStart

      • columnReorderingEnabled

        private final boolean columnReorderingEnabled

      • ignoreLeading

        protected boolean ignoreLeading

      • ignoreTrailing

        protected boolean ignoreTrailing

      • errorContentLength

        private final int errorContentLength

    • Constructor Detail

      • AbstractWriter

        public AbstractWriter​(S settings)
        All writers must support, at the very least, the settings provided by CommonWriterSettings. The AbstractWriter requires its configuration to be properly initialized. Important: by not providing an instance of Writer to this constructor, only the operations that write to Strings are available.
        Parameters:
        settings - the writer configuration

      • AbstractWriter

        public AbstractWriter​(java.io.File file,
                      S settings)
        All writers must support, at the very least, the settings provided by CommonWriterSettings. The AbstractWriter requires its configuration to be properly initialized.
        Parameters:
        file - the output file that will be written with the format-specific records as defined by subclasses of AbstractWriter.
        settings - the writer configuration

      • AbstractWriter

        public AbstractWriter​(java.io.File file,
                      java.lang.String encoding,
                      S settings)
        All writers must support, at the very least, the settings provided by CommonWriterSettings. The AbstractWriter requires its configuration to be properly initialized.
        Parameters:
        file - the output file that will be written with the format-specific records as defined by subclasses of AbstractWriter.
        encoding - the encoding of the file
        settings - the writer configuration

      • AbstractWriter

        public AbstractWriter​(java.io.File file,
                      java.nio.charset.Charset encoding,
                      S settings)
        All writers must support, at the very least, the settings provided by CommonWriterSettings. The AbstractWriter requires its configuration to be properly initialized.
        Parameters:
        file - the output file that will be written with the format-specific records as defined by subclasses of AbstractWriter.
        encoding - the encoding of the file
        settings - the writer configuration

      • AbstractWriter

        public AbstractWriter​(java.io.OutputStream output,
                      S settings)
        All writers must support, at the very least, the settings provided by CommonWriterSettings. The AbstractWriter requires its configuration to be properly initialized.
        Parameters:
        output - the output stream that will be written with the format-specific records as defined by subclasses of AbstractWriter.
        settings - the writer configuration

      • AbstractWriter

        public AbstractWriter​(java.io.OutputStream output,
                      java.lang.String encoding,
                      S settings)
        All writers must support, at the very least, the settings provided by CommonWriterSettings. The AbstractWriter requires its configuration to be properly initialized.
        Parameters:
        output - the output stream that will be written with the format-specific records as defined by subclasses of AbstractWriter.
        encoding - the encoding of the stream
        settings - the writer configuration

      • AbstractWriter

        public AbstractWriter​(java.io.OutputStream output,
                      java.nio.charset.Charset encoding,
                      S settings)
        All writers must support, at the very least, the settings provided by CommonWriterSettings. The AbstractWriter requires its configuration to be properly initialized.
        Parameters:
        output - the output stream that will be written with the format-specific records as defined by subclasses of AbstractWriter.
        encoding - the encoding of the stream
        settings - the writer configuration

      • AbstractWriter

        public AbstractWriter​(java.io.Writer writer,
                      S settings)
        All writers must support, at the very least, the settings provided by CommonWriterSettings. The AbstractWriter requires its configuration to be properly initialized.
        Parameters:
        writer - the output resource that will receive the format-specific records as defined by subclasses of AbstractWriter.
        settings - the writer configuration

    • Method Detail

      • enableNewlineAfterRecord

        protected void enableNewlineAfterRecord​(boolean enableNewlineAfterRecord)

      • initialize

        protected abstract void initialize​(S settings)
        Initializes the concrete implementation of this class with format-specific settings.
        Parameters:
        settings - the settings object specific to the format being written.

      • updateIndexesToWrite

        private void updateIndexesToWrite​(CommonSettings<?> settings)
        Update indexes to write based on the field selection provided by the user.

      • updateFieldSelection

        public void updateFieldSelection​(java.lang.String... newFieldSelection)
        Updates the selection of fields to write. This is useful if the input rows change during the writing process and their values need be allocated to specific columns.
        Parameters:
        newFieldSelection - the new selection of fields to write.

      • updateFieldSelection

        public void updateFieldSelection​(java.lang.Integer... newFieldSelectionByIndex)
        Updates the selection of fields to write. This is useful if the input rows change during the writing process and their values need be allocated to specific columns.
        Parameters:
        newFieldSelectionByIndex - the new selection of fields to write.

      • updateFieldExclusion

        public void updateFieldExclusion​(java.lang.String... fieldsToExclude)
        Updates the selection of fields to exclude when writing. This is useful if the input rows change during the writing process and their values need be allocated to specific columns.
        Parameters:
        fieldsToExclude - the selection of fields to exclude from the output.

      • updateFieldExclusion

        public void updateFieldExclusion​(java.lang.Integer... fieldIndexesToExclude)
        Updates the selection of fields to exclude when writing. This is useful if the input rows change during the writing process and their values need be allocated to specific columns.
        Parameters:
        fieldIndexesToExclude - the selection of fields to exclude from the output.

      • submitRow

        private void submitRow​(java.lang.Object[] row)
        Submits a row for processing by the format-specific implementation.
        Parameters:
        row - the data to be written for a single record in the output.

      • processRow

        protected abstract void processRow​(java.lang.Object[] row)
        Format-specific implementation for writing a single record into the output. The AbstractWriter handles the initialization and processing of the output until it is ready to be written (generally, reorganizing it and passing it on to a RowWriterProcessor). It then delegates the record to the writer-specific implementation defined by processRow(Object[]). In general, an implementation of processRow(Object[]) will perform the following steps:
        • Iterate over each object in the given input and convert it to the expected String representation.
        • The conversion must happen using the provided appender object. The an individual value is processed, the appendValueToRow() method must be called. This will clear the accumulated value in appender and add it to the output row.
        • Format specific separators and other characters must be introduced to the output row using appendToRow(char)
        Once the processRow(Object[]) method returns, a row will be written to the output with the processed information, and a newline will be automatically written after the given contents, unless this is a FixedWidthWriter whose FixedWidthWriterSettings.getWriteLineSeparatorAfterRecord() evaluates to false. The newline character sequence will conform to what is specified in Format.getLineSeparator() This cycle repeats until the writing process is stopped by the user or an error happens. In case of errors, the unchecked exception TextWritingException will be thrown and all resources in use will be closed automatically. The exception should contain the cause and more information about the output state when the error happened.
        Parameters:
        row - the data to be written to the output in the expected format.
        See Also:
        CharAppender, CommonWriterSettings

      • appendValueToRow

        protected final void appendValueToRow()
        Appends the processed sequence of characters in appender to the output row.

      • appendToRow

        protected final void appendToRow​(char ch)
        Appends the given character to the output row.
        Parameters:
        ch - the character to append to the output row

      • appendToRow

        protected final void appendToRow​(char[] chars)
        Appends the given character sequence to the output row
        Parameters:
        chars - the sequence of characters to append to the output row

      • writeHeaders

        public final void writeHeaders​(java.util.Collection<?> headers)
        Writes the given collection of headers to the output. A TextWritingException will be thrown if no headers were defined or if records were already written to the output.
        Parameters:
        headers - the headers to write to the output.

      • writeHeaders

        public final void writeHeaders​(java.lang.String... headers)
        Writes the given collection of headers to the output. A TextWritingException will be thrown if no headers were defined or if records were already written to the output.
        Parameters:
        headers - the headers to write to the output.

      • processRecord

        public final <T extends Record> void processRecord​(T record)

      • writeRowsAndClose

        public final <C extends java.util.Collection<?>> void writeRowsAndClose​(java.lang.Iterable<C> allRows)
        Iterates over all records, writes them and closes the output. Note this method will not use the RowWriterProcessor. Use processRecordsAndClose(Iterable) for that.
        Type Parameters:
        C - Collection of objects containing values of a row
        Parameters:
        allRows - the rows to be written to the output

      • writeRowsAndClose

        public final void writeRowsAndClose​(java.util.Collection<java.lang.Object[]> allRows)
        Iterates over all records, writes them and closes the output. Note this method will not use the RowWriterProcessor. Use processRecordsAndClose(Object[]) for that.
        Parameters:
        allRows - the rows to be written to the output

      • writeStringRowsAndClose

        public final void writeStringRowsAndClose​(java.util.Collection<java.lang.String[]> allRows)
        Iterates over all records, writes them and closes the output. Note this method will not use the RowWriterProcessor. Use processRecordsAndClose(Iterable) for that.
        Parameters:
        allRows - the rows to be written to the output

      • writeRecordsAndClose

        public final void writeRecordsAndClose​(java.util.Collection<? extends Record> allRows)
        Iterates over all records, writes them and closes the output. Note this method will not use the RowWriterProcessor. Use processRecordsAndClose(Iterable) for that.
        Parameters:
        allRows - the rows to be written to the output

      • writeRowsAndClose

        public final void writeRowsAndClose​(java.lang.Object[][] allRows)
        Iterates over all records, writes them and closes the output. Note this method will not use the RowWriterProcessor. Use processRecordsAndClose(Object[]) for that.
        Parameters:
        allRows - the rows to be written to the output

      • writeRows

        public final void writeRows​(java.lang.Object[][] rows)
        Iterates over all records and writes them to the output. The output will remain open for further writing. Note this method will not use the RowWriterProcessor. Use processRecords(Object[]) for that.
        Parameters:
        rows - the rows to be written to the output

      • writeRows

        public final <C extends java.util.Collection<?>> void writeRows​(java.lang.Iterable<C> rows)
        Iterates over all records and writes them to the output. The output will remain open for further writing. Note this method will not use the RowWriterProcessor. Use processRecords(Iterable) for that.
        Type Parameters:
        C - Collection of objects containing values of a row
        Parameters:
        rows - the rows to be written to the output

      • writeStringRows

        public final void writeStringRows​(java.util.Collection<java.lang.String[]> rows)
        Iterates over all records and writes them to the output. The output will remain open for further writing. Note this method will not use the RowWriterProcessor. Use processRecords(Iterable) for that.
        Parameters:
        rows - the rows to be written to the output

      • writeRecords

        public final void writeRecords​(java.util.Collection<? extends Record> rows)
        Iterates over all records and writes them to the output. The output will remain open for further writing. Note this method will not use the RowWriterProcessor. Use processRecords(Iterable) for that.
        Parameters:
        rows - the rows to be written to the output

      • writeStringRows

        public final <C extends java.util.Collection<?>> void writeStringRows​(java.lang.Iterable<C> rows)
        Iterates over all records and writes them to the output. The output will remain open for further writing. Note this method will not use the RowWriterProcessor. Use processRecords(Iterable) for that.
        Type Parameters:
        C - Collection of objects containing values of a row
        Parameters:
        rows - the rows to be written to the output

      • writeRows

        public final void writeRows​(java.util.Collection<java.lang.Object[]> rows)
        Iterates over all records and writes them to the output. The output will remain open for further writing. Note this method will not use the RowWriterProcessor. Use processRecords(Iterable) for that.
        Parameters:
        rows - the rows to be written to the output

      • writeRow

        public final void writeRow​(java.util.Collection<?> row)
        Writes the data given for an individual record. The output will remain open for further writing. Note this method will not use the RowWriterProcessor. Use processRecord(Object) for that.
        Parameters:
        row - the information of a single record to be written to the output

      • writeRecord

        public final <T extends Record> void writeRecord​(T row)
        Writes the data given for an individual record. The output will remain open for further writing. If the given data is null or empty, and CommonSettings.getSkipEmptyLines() is true, the input will be just ignored. If CommonSettings.getSkipEmptyLines() is false, then an empty row will be written to the output (as specified by writeEmptyRow()). In case of any errors, a TextWritingException will be thrown and the Writer given in the constructor will be closed. Note this method will not use the RowWriterProcessor. Use processRecord(Object) for that.
        Type Parameters:
        T - the concrete Record type
        Parameters:
        row - the information of a single record to be written to the output

      • expand

        protected java.lang.Object[] expand​(java.lang.Object[] row,
                                    int length,
                                    java.lang.Integer h2)

      • writeRow

        public final void writeRow​(java.lang.String row)
        Writes a plain (potentially free-text) String as a line to the output. A newline will automatically written after the given contents, unless this is a FixedWidthWriter whose FixedWidthWriterSettings.getWriteLineSeparatorAfterRecord() evaluates to false. The newline character sequence will conform to what is specified in Format.getLineSeparator() The writer implementation has no control over the format of this content. The output will remain open for further writing.
        Parameters:
        row - the line to be written to the output

      • commentRow

        public final void commentRow​(java.lang.String comment)
        Writes a comment row to the output. A newline will automatically written after the given contents, unless this is a FixedWidthWriter whose FixedWidthWriterSettings.getWriteLineSeparatorAfterRecord() evaluates to false. The newline character sequence will conform to what is specified in Format.getLineSeparator() The output will remain open for further writing.
        Parameters:
        comment - the contents to be written as a comment to the output

      • fillOutputRow

        private <T> void fillOutputRow​(T[] row)
        Used when fields were selected and the input rows have a different order than the output. This method fills the internal #outputRow array with the values provided by the user in the correct order.
        Parameters:
        row - user-provided data which has to be rearranged to the expected record sequence before writing to the output.

      • internalWriteRow

        private void internalWriteRow()
        Writes the accumulated value of a record to the output, followed by a newline, and increases the record count. The newline character sequence will conform to what is specified in Format.getLineSeparator() The contents of rowAppender depend on the concrete implementation of processRow(Object[])

      • skipLeadingWhitespace

        protected static int skipLeadingWhitespace​(int whitespaceRangeStart,
                                           java.lang.String element)
        Identifies the starting character index of a value being written if leading whitespaces are to be discarded. Implementation note whitespaces are considered all characters where ch <= ' ' evaluates to true
        Parameters:
        whitespaceRangeStart - starting range after which characters will be considered whitespace
        element - the String to be scanned for leading whitespaces.
        Returns:
        the index of the first non-whitespace character in the given element.

      • flush

        public final void flush()
        Flushes the Writer given in this class constructor. An IllegalStateException will be thrown in case of any errors, and the writer will be closed.

      • close

        public final void close()
        Closes the Writer given in this class constructor. An IllegalStateException will be thrown in case of any errors.

      • throwExceptionAndClose

        private TextWritingException throwExceptionAndClose​(java.lang.String message)
        In case of any exceptions, a TextWritingException is thrown, and the output Writer is closed.
        Parameters:
        message - Description of the error

      • throwExceptionAndClose

        private TextWritingException throwExceptionAndClose​(java.lang.String message,
                                                    java.lang.Throwable cause)
        In case of any exceptions, a TextWritingException is thrown, and the output Writer is closed.
        Parameters:
        message - Description of the error
        cause - the exception to be wrapped by a TextWritingException

      • throwExceptionAndClose

        private TextWritingException throwExceptionAndClose​(java.lang.String message,
                                                    java.lang.String recordCharacters,
                                                    java.lang.Throwable cause)
        In case of any exceptions, a TextWritingException is thrown, and the output Writer is closed.
        Parameters:
        message - Description of the error
        recordCharacters - characters used to write to the output at the time the exception happened
        cause - the exception to be wrapped by a TextWritingException

      • throwExceptionAndClose

        private TextWritingException throwExceptionAndClose​(java.lang.String message,
                                                    java.lang.Object[] recordValues,
                                                    java.lang.Throwable cause)
        In case of any exceptions, a TextWritingException is thrown, and the output Writer is closed.
        Parameters:
        message - Description of the error
        recordValues - values used to write to the output at the time the exception happened
        cause - the exception to be wrapped by a TextWritingException

      • getStringValue

        protected java.lang.String getStringValue​(java.lang.Object element)
        Converts a given object to its String representation for writing to a String
        • If the object is null, then nullValue is returned.
        • If the String representation of this object is an empty String, then emptyValue is returned
        Parameters:
        element - the object to be converted into a String.
        Returns:
        the String representation of the given object

      • addValues

        public final void addValues​(java.lang.Object... values)
        Writes a sequence of values to a row in memory. Subsequent calls to this method will add the given values in a new column of the same row, until writeValuesToRow() is called to flush all values accumulated and effectively write a new record to the output
        Parameters:
        values - the values to be written

      • addStringValues

        public final void addStringValues​(java.util.Collection<java.lang.String> values)
        Writes a sequence of Strings to a row in memory. Subsequent calls to this method will add the given values in a new column of the same row, until writeValuesToRow() is called to flush all values accumulated and effectively write a new record to the output
        Parameters:
        values - the values to be written

      • addValues

        public final void addValues​(java.util.Collection<?> values)
        Writes a sequence of values to a row in memory. Subsequent calls to this method will add the given values in a new column of the same row, until writeValuesToRow() is called to flush all values accumulated and effectively write a new record to the output
        Parameters:
        values - the values to be written

      • addValue

        public final void addValue​(java.lang.Object value)
        Writes a value to a row in memory. Subsequent calls to this method will add the given values in a new column of the same row, until writeValuesToRow() is called to flush all values accumulated and effectively write a new record to the output
        Parameters:
        value - the value to be written

      • fillPartialLineToMatchHeaders

        private void fillPartialLineToMatchHeaders()

      • writeValuesToRow

        public final void writeValuesToRow()
        Writes the contents accumulated in an internal in-memory row (using or #writeValue() to a new record in the output.

      • addValue

        public final void addValue​(int index,
                           java.lang.Object value)
        Writes a value to a row in memory. Subsequent calls to this method will add the given values in a new column of the same row, until writeValuesToRow() is called to flush all values accumulated and effectively write a new record to the output
        Parameters:
        index - the position in the row that should receive the value.
        value - the value to be written

      • addValue

        public final void addValue​(java.lang.String headerName,
                           java.lang.Object value)
        Writes a value to a row in memory. Subsequent calls to this method will add the given values in a new column of the same row, until writeValuesToRow() is called to flush all values accumulated and effectively write a new record to the output
        Parameters:
        headerName - the name of the column of the new row that should receive the value.
        value - the value to be written

      • addValue

        private final void addValue​(NormalizedString[] headersInContext,
                            NormalizedString headerName,
                            boolean ignoreOnMismatch,
                            java.lang.Object value)

      • getFieldIndex

        private int getFieldIndex​(NormalizedString[] headersInContext,
                          NormalizedString headerName,
                          boolean ignoreOnMismatch)
        Calculates the index of a header name in relation to the original headers array defined in this writer
        Parameters:
        headersInContext - headers currently in use (they might change).
        headerName - the name of the header whose position will be identified
        ignoreOnMismatch - flag indicating that if the header is not found, no exception is to be thrown, and -1 should be returned instead.
        Returns:
        the position of the given header, or -1 if it's not found when ignoreOnMismatch is set to true

      • discardValues

        public final void discardValues()
        Discards the contents written to the internal in-memory row (using or #writeValue().

      • writeHeadersToString

        public final java.lang.String writeHeadersToString​(java.util.Collection<?> headers)
        Writes the given collection of headers to a String A TextWritingException will be thrown if no headers were defined.
        Parameters:
        headers - the headers to write to a String
        Returns:
        a formatted String containing the given headers

      • writeHeadersToString

        public final java.lang.String writeHeadersToString​(java.lang.String... headers)
        Writes the given collection of headers to a String A TextWritingException will be thrown if no headers were defined or if records were already written to a String
        Parameters:
        headers - the headers to write to a String
        Returns:
        a formatted String containing the given headers

      • writeRowsToString

        public final java.util.List<java.lang.String> writeRowsToString​(java.lang.Object[][] rows)
        Iterates over all records and writes them to a List of String. Note this method will not use the RowWriterProcessor. Use processRecords(Object[]) for that.
        Parameters:
        rows - the rows to be written to a List of String.
        Returns:
        a List containing the given rows as formatted Strings

      • writeRowsToString

        public final <C extends java.util.Collection<?>> java.util.List<java.lang.String> writeRowsToString​(java.lang.Iterable<C> rows)
        Iterates over all records and writes them to a List of String. Note this method will not use the RowWriterProcessor. Use processRecords(Iterable) for that.
        Type Parameters:
        C - Collection of objects containing values of a row
        Parameters:
        rows - the rows to be written to a List of String.
        Returns:
        a List containing the given rows as formatted Strings

      • writeStringRowsToString

        public final <C extends java.util.Collection<?>> java.util.List<java.lang.String> writeStringRowsToString​(java.lang.Iterable<C> rows)
        Iterates over all records and writes them to a List of String. Note this method will not use the RowWriterProcessor. Use processRecords(Iterable) for that.
        Type Parameters:
        C - Collection of objects containing values of a row
        Parameters:
        rows - the rows to be written to a List of String.
        Returns:
        a List containing the given rows as formatted Strings

      • writeRowsToString

        public final java.util.List<java.lang.String> writeRowsToString​(java.util.Collection<java.lang.Object[]> rows)
        Iterates over all records and writes them to a List of String. Note this method will not use the RowWriterProcessor. Use processRecords(Iterable) for that.
        Parameters:
        rows - the rows to be written to a List of String.
        Returns:
        a List containing the given rows as formatted Strings

      • writeStringRowsToString

        public final java.util.List<java.lang.String> writeStringRowsToString​(java.util.Collection<java.lang.String[]> rows)
        Iterates over all records and writes them to a List of String. Note this method will not use the RowWriterProcessor. Use processRecords(Iterable) for that.
        Parameters:
        rows - the rows to be written to a List of String.
        Returns:
        a List containing the given rows as formatted Strings

      • writeRecordsToString

        public final java.util.List<java.lang.String> writeRecordsToString​(java.util.Collection<? extends Record> rows)
        Iterates over all records and writes them to a List of String. Note this method will not use the RowWriterProcessor. Use processRecords(Iterable) for that.
        Parameters:
        rows - the rows to be written to a List of String.
        Returns:
        a List containing the given rows as formatted Strings

      • writeRowToString

        public final java.lang.String writeRowToString​(java.util.Collection<?> row)
        Writes the data given for an individual record to a String. Note this method will not use the RowWriterProcessor. Use processRecord(Object) for that.
        Parameters:
        row - the information of a single record to be written to a String
        Returns:
        a formatted String containing the information of the given record

      • writeRowToString

        public final java.lang.String writeRowToString​(java.lang.String[] row)
        Writes the data given for an individual record to a String. If the given data is null or empty, and CommonSettings.getSkipEmptyLines() is true, null will be returned In case of any errors, a TextWritingException will be thrown. Note this method will not use the RowWriterProcessor. Use processRecord(Object) for that.
        Parameters:
        row - the information of a single record to be written to a String.
        Returns:
        a formatted String containing the information of the given record

      • writeRecordToString

        public final <T extends Record> java.lang.String writeRecordToString​(T row)
        Writes the data given for an individual record to a String. If the given data is null or empty, and CommonSettings.getSkipEmptyLines() is true, null will be returned In case of any errors, a TextWritingException will be thrown. Note this method will not use the RowWriterProcessor. Use processRecord(Object) for that.
        Parameters:
        row - the information of a single record to be written to a String.
        Returns:
        a formatted String containing the information of the given record

      • writeRowToString

        public final java.lang.String writeRowToString​(java.lang.Object... row)
        Writes the data given for an individual record to a String. If the given data is null or empty, and CommonSettings.getSkipEmptyLines() is true, null will be returned In case of any errors, a TextWritingException will be thrown. Note this method will not use the RowWriterProcessor. Use processRecord(Object) for that.
        Parameters:
        row - the information of a single record to be written to a String.
        Returns:
        a formatted String containing the information of the given record

      • adjustRowLength

        private java.lang.Object[] adjustRowLength​(java.lang.Object[] row)

      • commentRowToString

        public final java.lang.String commentRowToString​(java.lang.String comment)
        Writes a comment row to a String
        Parameters:
        comment - the contents to be written as a comment to a String.
        Returns:
        a formatted String containing the comment.

      • internalWriteRowToString

        private java.lang.String internalWriteRowToString()
        Writes the accumulated value of a record to the output, followed by a newline, and increases the record count. The newline character sequence will conform to what is specified in Format.getLineSeparator() The contents of rowAppender depend on the concrete implementation of processRow(Object[])
        Returns:
        a formatted String containing the comment.

      • writeValuesToString

        public final java.lang.String writeValuesToString()
        Writes the contents accumulated in an internal in-memory row (using or #addValue() as a String
        Returns:
        a formatted String containing the information accumulated in the internal in-memory row.

      • getRecordCount

        public final long getRecordCount()
        Returns the number of records written to the output so far
        Returns:
        the number of records written to the output so far

      • writeValuesFromMap

        private <K> void writeValuesFromMap​(java.util.Map<K,​java.lang.String> headerMapping,
                                    java.util.Map<K,​?> rowData)
        Writes values from an implementation of Map to a partial output record, ready to be written to the output. Values will be stored under a column identified by the headers. If no headers are defined, the keys of the map will be used to initialize an internal header row. A map of headers can be optionally provided to assign a name to the keys of the input map. This is useful when the input map has keys will generate unwanted header names.
        Type Parameters:
        K - type of the key in both rowData and headerMapping maps.
        Parameters:
        headerMapping - an optional map associating keys of the rowData map with expected header names
        rowData - the data to be written. Its keys will be used to form a header row in case no headers are available.

      • setHeadersFromMap

        private void setHeadersFromMap​(java.util.Map<?,​?> map,
                               boolean keys)
        Iterates over the keys of a map and builds an internal header row.
        Parameters:
        map - the input map whose keys will be used to generate headers for the output.
        keys - indicates whether to take the map keys or values to build the header rows.

      • writeRowToString

        public final java.lang.String writeRowToString​(java.util.Map<?,​?> rowData)
        Writes the values of a given map to a String formatted to according to the specified output format. Note this method will not use the RowWriterProcessor.
        Parameters:
        rowData - the map whose values will be used to generate a String.
        Returns:
        a String containing the given data as a formatted String

      • writeRow

        public final void writeRow​(java.util.Map<?,​?> rowData)
        Writes the values of a given map into new output record Note this method will not use the RowWriterProcessor.
        Parameters:
        rowData - the map whose values will be used to generate a new record

      • writeRowToString

        public final <K> java.lang.String writeRowToString​(java.util.Map<K,​java.lang.String> headerMapping,
                                                   java.util.Map<K,​?> rowData)
        Writes the values of a given map to a String formatted to according to the specified output format. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a String.
        Returns:
        a String containing the given data as a formatted String

      • writeRow

        public final <K> void writeRow​(java.util.Map<K,​java.lang.String> headerMapping,
                               java.util.Map<K,​?> rowData)
        Writes the values of a given map into new output record Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a new record

      • writeRowsToString

        public final <K,​I extends java.lang.Iterable<?>> java.util.List<java.lang.String> writeRowsToString​(java.util.Map<K,​I> rowData)
        Writes the values of a given map to a List of String formatted to according to the specified output format. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        I - the iterable type
        Parameters:
        rowData - the map whose values will be used to generate a List of String.
        Returns:
        a List of formatted String, each String representing one successful iteration over at least one element of the iterators in the map.

      • writeRows

        public final <K,​I extends java.lang.Iterable<?>> void writeRows​(java.util.Map<K,​I> rowData)
        Writes the values of a given map to multiple output records Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        I - the iterable type
        Parameters:
        rowData - the map whose values will be used to generate a number of output records

      • writeRowsToString

        public final <K,​I extends java.lang.Iterable<?>> java.util.List<java.lang.String> writeRowsToString​(java.util.Map<K,​java.lang.String> headerMapping,
                                                                                                          java.util.Map<K,​I> rowData)
        Writes the values of a given map to a List of String formatted to according to the specified output format. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        I - the iterable type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a List of String.
        Returns:
        a List of formatted String, each String representing one successful iteration over at least one element of the iterators in the map.

      • writeRows

        public final <K,​I extends java.lang.Iterable<?>> void writeRows​(java.util.Map<K,​java.lang.String> headerMapping,
                                                                      java.util.Map<K,​I> rowData)
        Writes the values of a given map to multiple output records Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        I - the iterable type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a number of output records

      • writeRows

        private <K,​I extends java.lang.Iterable<?>> void writeRows​(java.util.Map<K,​java.lang.String> headerMapping,
                                                                 java.util.Map<K,​I> rowData,
                                                                 java.util.List<java.lang.String> outputList,
                                                                 boolean useRowProcessor)
        Writes the values of a given map to a List of String formatted to according to the specified output format. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        I - the iterable type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a List of String.
        outputList - an output List to fill with formatted Strings, each String representing one successful iteration over at least one element of the iterators in the map.

      • writeStringRowsToString

        public final <K> java.util.List<java.lang.String> writeStringRowsToString​(java.util.Map<K,​java.lang.String> headerMapping,
                                                                          java.util.Map<K,​java.lang.String[]> rowData)
        Writes the values of a given map to a List of String formatted to according to the specified output format. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a List of String.
        Returns:
        a List of formatted String, each String representing one successful iteration over at least one element of the iterators in the map.

      • writeRecordsToString

        public final <K> java.util.List<java.lang.String> writeRecordsToString​(java.util.Map<K,​java.lang.String> headerMapping,
                                                                       java.util.Map<K,​? extends Record> rowData)
        Writes the values of a given map to a List of String formatted to according to the specified output format. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a List of String.
        Returns:
        a List of formatted String, each String representing one successful iteration over at least one element of the iterators in the map.

      • writeStringRows

        public final <K> void writeStringRows​(java.util.Map<K,​java.lang.String> headerMapping,
                                      java.util.Map<K,​java.lang.String[]> rowData)
        Writes the values of a given map to multiple output records Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a number of output records

      • writeRecords

        public final <K> void writeRecords​(java.util.Map<K,​java.lang.String> headerMapping,
                                   java.util.Map<K,​? extends Record> rowData)
        Writes the values of a given map to multiple output records Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a number of output records

      • writeObjectRowsToString

        public final <K> java.util.List<java.lang.String> writeObjectRowsToString​(java.util.Map<K,​java.lang.String> headerMapping,
                                                                          java.util.Map<K,​java.lang.Object[]> rowData)
        Writes the values of a given map to a List of String formatted to according to the specified output format. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a List of String.
        Returns:
        a List of formatted String, each String representing one successful iteration over at least one element of the iterators in the map.

      • writeObjectRows

        public final <K> void writeObjectRows​(java.util.Map<K,​java.lang.String> headerMapping,
                                      java.util.Map<K,​java.lang.Object[]> rowData)
        Writes the values of a given map to multiple output records Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a number of output records

      • wrapObjectArray

        private <K> java.util.Map<K,​java.lang.Iterable<java.lang.Object>> wrapObjectArray​(java.util.Map<K,​java.lang.Object[]> rowData)

      • wrapStringArray

        private <K> java.util.Map<K,​java.lang.Iterable<java.lang.String>> wrapStringArray​(java.util.Map<K,​java.lang.String[]> rowData)

      • wrapRecordValues

        private <K> java.util.Map<K,​java.lang.Iterable<java.lang.String>> wrapRecordValues​(java.util.Map<K,​? extends Record> rowData)

      • writeObjectRowsAndClose

        public final <K> void writeObjectRowsAndClose​(java.util.Map<K,​java.lang.String> headerMapping,
                                              java.util.Map<K,​java.lang.Object[]> rowData)
        Writes the values of a given map to multiple output records and closes the output when finished. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a number of output records

      • writeStringRowsAndClose

        public final <K> void writeStringRowsAndClose​(java.util.Map<K,​java.lang.String> headerMapping,
                                              java.util.Map<K,​java.lang.String[]> rowData)
        Writes the values of a given map to multiple output records and closes the output when finished. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a number of output records

      • writeRecordsAndClose

        public final <K> void writeRecordsAndClose​(java.util.Map<K,​java.lang.String> headerMapping,
                                           java.util.Map<K,​? extends Record> rowData)
        Writes the values of a given map to multiple output records and closes the output when finished. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a number of output records

      • writeObjectRowsAndClose

        public final <K> void writeObjectRowsAndClose​(java.util.Map<K,​java.lang.Object[]> rowData)
        Writes the values of a given map to multiple output records and closes the output when finished. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        Parameters:
        rowData - the map whose values will be used to generate a number of output records

      • writeStringRowsAndClose

        public final <K> void writeStringRowsAndClose​(java.util.Map<K,​java.lang.String[]> rowData)
        Writes the values of a given map to multiple output records and closes the output when finished. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        Parameters:
        rowData - the map whose values will be used to generate a number of output records

      • writeRecordsAndClose

        public final <K> void writeRecordsAndClose​(java.util.Map<K,​? extends Record> rowData)
        Writes the values of a given map to multiple output records and closes the output when finished. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        Parameters:
        rowData - the map whose values will be used to generate a number of output records

      • writeRowsAndClose

        public final <K,​I extends java.lang.Iterable<?>> void writeRowsAndClose​(java.util.Map<K,​java.lang.String> headerMapping,
                                                                              java.util.Map<K,​I> rowData)
        Writes the values of a given map to multiple output records and closes the output when finished. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        I - the iterable type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a number of output records

      • writeRowsAndClose

        public final <K,​I extends java.lang.Iterable<?>> void writeRowsAndClose​(java.util.Map<K,​I> rowData)
        Writes the values of a given map to multiple output records and closes the output when finished. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. Note this method will not use the RowWriterProcessor.
        Type Parameters:
        K - the key type
        I - the iterable type
        Parameters:
        rowData - the map whose values will be used to generate a number of output records

      • processRecordToString

        public final <K> java.lang.String processRecordToString​(java.util.Map<K,​java.lang.String> headerMapping,
                                                        java.util.Map<K,​?> rowData)
        Processes the values of a map using the RowWriterProcessor provided by CommonWriterSettings.getRowWriterProcessor() and writes the result into String formatted according to the specified output format. A TextWritingException will be thrown if no RowWriterProcessor is provided by CommonWriterSettings.getRowWriterProcessor().
        Type Parameters:
        K - the key type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a List of String.
        Returns:
        a String containing the given data as a formatted String

      • processRecordsToString

        public final <K,​I extends java.lang.Iterable<?>> java.util.List<java.lang.String> processRecordsToString​(java.util.Map<K,​I> rowData)
        Processes the data in all values of a map using the RowWriterProcessor provided by CommonWriterSettings.getRowWriterProcessor() and writes the result into a List of String formatted to according to the specified output format. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A TextWritingException will be thrown if no RowWriterProcessor is provided by CommonWriterSettings.getRowWriterProcessor().
        Type Parameters:
        K - the key type
        I - the iterable type
        Parameters:
        rowData - the map whose values will be used to generate a List of String.
        Returns:
        a List of formatted String, each String representing one successful iteration over at least one element of the iterators in the map.

      • processRecordsToString

        public final <K,​I extends java.lang.Iterable<?>> java.util.List<java.lang.String> processRecordsToString​(java.util.Map<K,​java.lang.String> headerMapping,
                                                                                                               java.util.Map<K,​I> rowData)
        Processes the data in all values of a map using the RowWriterProcessor provided by CommonWriterSettings.getRowWriterProcessor() and writes the result into a List of String formatted to according to the specified output format. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A TextWritingException will be thrown if no RowWriterProcessor is provided by CommonWriterSettings.getRowWriterProcessor().
        Type Parameters:
        K - the key type
        I - the iterable type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a List of String.
        Returns:
        a List of formatted String, each String representing one successful iteration over at least one element of the iterators in the map.

      • processRecords

        public final <K,​I extends java.lang.Iterable<?>> void processRecords​(java.util.Map<K,​java.lang.String> headerMapping,
                                                                           java.util.Map<K,​I> rowData)
        Processes the data in all values of a map using the RowWriterProcessor provided by CommonWriterSettings.getRowWriterProcessor(), then writes all values to the output . The output will remain open for further write operations. A TextWritingException will be thrown if no RowWriterProcessor is provided by CommonWriterSettings.getRowWriterProcessor().
        Type Parameters:
        K - the key type
        I - the iterable type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a number of output records

      • processObjectRecordsToString

        public final <K> java.util.List<java.lang.String> processObjectRecordsToString​(java.util.Map<K,​java.lang.Object[]> rowData)
        Processes the data in all values of a map using the RowWriterProcessor provided by CommonWriterSettings.getRowWriterProcessor() and writes the result into a List of String formatted to according to the specified output format. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A TextWritingException will be thrown if no RowWriterProcessor is provided by CommonWriterSettings.getRowWriterProcessor().
        Type Parameters:
        K - the key type
        Parameters:
        rowData - the map whose values will be used to generate a List of String.
        Returns:
        a List of formatted String, each String representing one successful iteration over at least one element of the iterators in the map.

      • processObjectRecordsToString

        public final <K> java.util.List<java.lang.String> processObjectRecordsToString​(java.util.Map<K,​java.lang.String> headerMapping,
                                                                               java.util.Map<K,​java.lang.Object[]> rowData)
        Processes the data in all values of a map using the RowWriterProcessor provided by CommonWriterSettings.getRowWriterProcessor() and writes the result into a List of String formatted to according to the specified output format. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A TextWritingException will be thrown if no RowWriterProcessor is provided by CommonWriterSettings.getRowWriterProcessor().
        Type Parameters:
        K - the key type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a List of String.
        Returns:
        a List of formatted String, each String representing one successful iteration over at least one element of the iterators in the map.

      • processObjectRecords

        public final <K> void processObjectRecords​(java.util.Map<K,​java.lang.String> headerMapping,
                                           java.util.Map<K,​java.lang.Object[]> rowData)
        Processes the data in all values of a map using the RowWriterProcessor provided by CommonWriterSettings.getRowWriterProcessor(), then writes all values to the output . The output will remain open for further write operations. A TextWritingException will be thrown if no RowWriterProcessor is provided by CommonWriterSettings.getRowWriterProcessor().
        Type Parameters:
        K - the key type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a number of output records

      • processObjectRecordsAndClose

        public final <K> void processObjectRecordsAndClose​(java.util.Map<K,​java.lang.String> headerMapping,
                                                   java.util.Map<K,​java.lang.Object[]> rowData)
        Processes the data in all values of a map using the RowWriterProcessor provided by CommonWriterSettings.getRowWriterProcessor(), then writes all values to the output and closes the writer. A TextWritingException will be thrown if no RowWriterProcessor is provided by CommonWriterSettings.getRowWriterProcessor().
        Type Parameters:
        K - the key type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a number of output records

      • processRecordsAndClose

        public final <K,​I extends java.lang.Iterable<?>> void processRecordsAndClose​(java.util.Map<K,​java.lang.String> headerMapping,
                                                                                   java.util.Map<K,​I> rowData)
        Processes the data in all values of a map using the RowWriterProcessor provided by CommonWriterSettings.getRowWriterProcessor(), then writes all values to the output and closes the writer. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. A TextWritingException will be thrown if no RowWriterProcessor is provided by CommonWriterSettings.getRowWriterProcessor().
        Type Parameters:
        K - the key type
        I - the iterable type
        Parameters:
        headerMapping - a mapping associating the keys of the input map to their corresponding header names.
        rowData - the map whose values will be used to generate a number of output records

      • processRecordsAndClose

        public final <K,​I extends java.lang.Iterable<?>> void processRecordsAndClose​(java.util.Map<K,​I> rowData)
        Processes the data in all values of a map using the RowWriterProcessor provided by CommonWriterSettings.getRowWriterProcessor(), then writes all values to the output and closes the writer. Each value is expected to be iterable and the result of this method will produce the number of records equal to the longest iterable. A new record will be created each time at least one Iterator.hasNext() returns true. Null will be written when a iterator has been fully read. A TextWritingException will be thrown if no RowWriterProcessor is provided by CommonWriterSettings.getRowWriterProcessor().
        Type Parameters:
        K - the key type
        I - the iterable type
        Parameters:
        rowData - the map whose values will be used to generate a number of output records

      • getContent

        private java.lang.Object[] getContent​(java.lang.Object[] tmp)

      • getContent

        private java.lang.String getContent​(java.lang.CharSequence tmp)

      • allowTrim

        protected final boolean allowTrim​(int fieldIndex)
        Checks whether the writer can remove trailing/leading whitespaces from a value being written. Applies to headers where names can be conflicting if trimmed for example ' a ' and 'a' will become the same value if the spaces are removed)
        Parameters:
        fieldIndex - index of the field to be written.
        Returns:
        true if the value being written is not a header name, or it is a header name that won't conflict with another header if its surrounding whitespaces are trimmed.