Package org.jdom2.output.support

Class AbstractXMLOutputProcessor

java.lang.Object

org.jdom2.output.support.AbstractOutputProcessor

org.jdom2.output.support.AbstractXMLOutputProcessor

All Implemented Interfaces:

XMLOutputProcessor

public abstract class AbstractXMLOutputProcessor
extends AbstractOutputProcessor
implements XMLOutputProcessor

This class provides a concrete implementation of XMLOutputProcessor for supporting the XMLOutputter.

Overview

This class is marked abstract even though all methods are fully implemented. The process*(...) methods are public because they match the XMLOutputProcessor interface but the remaining methods are all protected.

People who want to create a custom XMLOutputProcessor for XMLOutputter are able to extend this class and modify any functionality they want. Before sub-classing this you should first check to see if the Format class can get you the results you want.

Subclasses of this should have reentrant methods. This is easiest to accomplish simply by not allowing any instance fields. If your sub-class has an instance field/variable, then it's probably broken.

The Stacks

One significant feature of this implementation is that it creates and maintains both a NamespaceStack and FormatStack that are managed in the printElement(Writer, FormatStack, NamespaceStack, Element) method. The stacks are pushed and popped in that method only. They significantly improve the performance and readability of the code.

The NamespaceStack is only sent through to the printElement(Writer, FormatStack, NamespaceStack, Element) and printContent(Writer, FormatStack, NamespaceStack, Walker) methods, but the FormatStack is pushed through to all print* Methods.

Text Processing

In XML the concept of 'Text' can be loosely defined as anything that can be found between an Element's start and end tags, excluding Comments and Processing Instructions. When considered from a JDOM perspective, this means Text, CDATA and EntityRef content. This will be referred to as 'Text-like content'

XMLOutputter delegates the management and formatting of Content to a Walker instance. See Walker and its various implementations for details on how the Element content is processed.

Because the Walker interface specifies that Text/CDATA content may be returned as either Text/CDATA instances or as formatted String values this class sometimes uses printCDATA(...) and printText(...), and sometimes uses the more direct textCDATA(Writer, String) or textRaw(Writer, String) as appropriate. In other words, subclasses should probably override these second methods instead of the print methods.

Non-Text Content

Non-text content is processed via the respective print* methods. The usage should be logical based on the method name.

The general observations are:

• printElement - maintains the Stacks, prints the element open tags, with attributes and namespaces. It checks to see whether the Element is text-only, or has non-text content. If it is text-only there is no indent/newline handling and it delegates to the correct text-type print method, otherwise it delegates to printContent.
• printContent is called to output all lists of Content. It assumes that all whitespace indentation/newlines are appropriate before it is called, but it will ensure that padding is appropriate between the items in the list.

Final Notes

No methods actually write to the destination Writer except the write(...) methods. Thus, all other methods do their respective processing and delegate the actual destination output to the write(Writer, char) or write(Writer, String) methods.

All Text-like content (printCDATA, printText, and printEntityRef) will ultimately be output through the the text* methods (and no other content).

Since:

JDOM2

Author:

Rolf Lear

See Also:

• XMLOutputter
• XMLOutputProcessor

Field Summary

Fields

Modifier and Type	Field	Description
protected static final String	CDATAPOST	Simple constant for a close-CDATA
protected static final String	CDATAPRE	Simple constant for an open-CDATA

Constructor Summary

Constructors

Constructor	Description
AbstractXMLOutputProcessor()

Method Summary

Modifier and Type	Method	Description
protected void	attributeEscapedEntitiesFilter(Writer out, FormatStack fstack, String value)	This will take the three pre-defined entities in XML 1.0 ('<', '>', and '&' - used specifically in XML elements) as well as CR/NL and Quote characters which require escaping inside Attribute values and convert their character representation to the appropriate entity reference suitable for XML attribute content.
protected void	printAttribute(Writer out, FormatStack fstack, Attribute attribute)	This will handle printing of an Attribute.
protected void	printCDATA(Writer out, FormatStack fstack, CDATA cdata)	This will handle printing of a CDATA.
protected void	printComment(Writer out, FormatStack fstack, Comment comment)	This will handle printing of a Comment.
protected void	printContent(Writer out, FormatStack fstack, NamespaceStack nstack, Walker walker)	This will handle printing of a List of Content.
protected void	printDeclaration(Writer out, FormatStack fstack)	This will handle printing of the XML declaration.
protected void	printDocType(Writer out, FormatStack fstack, DocType docType)	This will handle printing of a DocType.
protected void	printDocument(Writer out, FormatStack fstack, NamespaceStack nstack, Document doc)	This will handle printing of a Document.
protected void	printElement(Writer out, FormatStack fstack, NamespaceStack nstack, Element element)	This will handle printing of an Element.
protected void	printEntityRef(Writer out, FormatStack fstack, EntityRef entity)	This will handle printing of an EntityRef.
protected void	printNamespace(Writer out, FormatStack fstack, Namespace ns)	This will handle printing of any needed Namespace declarations.
protected void	printProcessingInstruction(Writer out, FormatStack fstack, ProcessingInstruction pi)	This will handle printing of a ProcessingInstruction.
protected void	printText(Writer out, FormatStack fstack, Text text)	This will handle printing of a Text.
void	process(Writer out, Format format, List<? extends Content> list)	This will handle printing out a list of nodes.
void	process(Writer out, Format format, CDATA cdata)	Print out a CDATA node.
void	process(Writer out, Format format, Comment comment)	Print out a Comment.
void	process(Writer out, Format format, DocType doctype)	Print out the DocType.
void	process(Writer out, Format format, Document doc)	This will print the Document to the given Writer.
void	process(Writer out, Format format, Element element)	Print out an Element, including its Attributes, and all contained (child) elements, etc.
void	process(Writer out, Format format, EntityRef entity)	Print out a EntityRef.
void	process(Writer out, Format format, ProcessingInstruction pi)	Print out a ProcessingInstruction.
void	process(Writer out, Format format, Text text)	Print out a Text node.
protected void	textCDATA(Writer out, String text)	Write a CDATA to the destination
protected void	textEntityRef(Writer out, String name)	Write an EntityRef to the destination.
protected void	textRaw(Writer out, char ch)	Convenience method that simply passes the input char to write(Writer, char).
protected void	textRaw(Writer out, String str)	Convenience method that simply passes the input str to write(Writer, String).
protected void	write(Writer out, char c)	Write a single character to the output Writer.
protected void	write(Writer out, String str)	Print some string value to the output.

Methods inherited from class org.jdom2.output.support.AbstractOutputProcessor

buildWalker

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

CDATAPRE

protected static final String CDATAPRE

Simple constant for an open-CDATA

See Also:

• Constant Field Values

CDATAPOST

protected static final String CDATAPOST

Simple constant for a close-CDATA

See Also:

• Constant Field Values

Constructor Details

AbstractXMLOutputProcessor

public AbstractXMLOutputProcessor()

Method Details

process

public void process(Writer out,
 Format format,
 Document doc)
             throws IOException

Description copied from interface: XMLOutputProcessor

This will print the Document to the given Writer.

Warning: using your own Writer may cause the outputter's preferred character encoding to be ignored. If you use encodings other than UTF-8, we recommend using the method that takes an OutputStream instead.

Specified by:

process in interface XMLOutputProcessor

Parameters:

out - Writer to use.

format - Format instance specifying output style

doc - Document to format.

Throws:

IOException - if there's any problem writing.

process

public void process(Writer out,
 Format format,
 DocType doctype)
             throws IOException

Description copied from interface: XMLOutputProcessor

Print out the DocType.

Specified by:

process in interface XMLOutputProcessor

Parameters:

out - Writer to use.

format - Format instance specifying output style

doctype - DocType to output.

Throws:

IOException - if there's any problem writing.

process

public void process(Writer out,
 Format format,
 Element element)
             throws IOException

Description copied from interface: XMLOutputProcessor

Print out an Element, including its Attributes, and all contained (child) elements, etc.

Specified by:

process in interface XMLOutputProcessor

Parameters:

out - Writer to use.

format - Format instance specifying output style

element - Element to output.

Throws:

IOException - if there's any problem writing.

process

public void process(Writer out,
 Format format,
 List<? extends Content> list)
             throws IOException

Description copied from interface: XMLOutputProcessor

This will handle printing out a list of nodes. This can be useful for printing the content of an element that contains HTML, like "<description>JDOM is <b>fun>!</description>".

Specified by:

process in interface XMLOutputProcessor

Parameters:

out - Writer to use.

format - Format instance specifying output style

list - List of nodes.

Throws:

IOException - if there's any problem writing.

process

public void process(Writer out,
 Format format,
 CDATA cdata)
             throws IOException

Description copied from interface: XMLOutputProcessor

Print out a CDATA node.

Specified by:

process in interface XMLOutputProcessor

Parameters:

out - Writer to use.

format - Format instance specifying output style

cdata - CDATA to output.

Throws:

IOException - if there's any problem writing.

process

public void process(Writer out,
 Format format,
 Text text)
             throws IOException

Description copied from interface: XMLOutputProcessor

Print out a Text node. Performs the necessary entity escaping and whitespace stripping.

Specified by:

process in interface XMLOutputProcessor

Parameters:

out - Writer to use.

format - Format instance specifying output style

text - Text to output.

Throws:

IOException - if there's any problem writing.

process

public void process(Writer out,
 Format format,
 Comment comment)
             throws IOException

Description copied from interface: XMLOutputProcessor

Print out a Comment.

Specified by:

process in interface XMLOutputProcessor

Parameters:

out - Writer to use.

format - Format instance specifying output style

comment - Comment to output.

Throws:

IOException - if there's any problem writing.

process

public void process(Writer out,
 Format format,
 ProcessingInstruction pi)
             throws IOException

Description copied from interface: XMLOutputProcessor

Print out a ProcessingInstruction.

Specified by:

process in interface XMLOutputProcessor

Parameters:

out - Writer to use.

format - Format instance specifying output style

pi - ProcessingInstruction to output.

Throws:

IOException - if there's any problem writing.

process

public void process(Writer out,
 Format format,
 EntityRef entity)
             throws IOException

Description copied from interface: XMLOutputProcessor

Print out a EntityRef.

Specified by:

process in interface XMLOutputProcessor

Parameters:

out - Writer to use.

format - Format instance specifying output style

entity - EntityRef to output.

Throws:

IOException - if there's any problem writing.

write

protected void write(Writer out,
 String str)
              throws IOException

Print some string value to the output. Null values are ignored. This ignore-null property is used for a few tricks.

Parameters:

out - The Writer to write to.

str - The String to write (can be null).

Throws:

IOException - if the out Writer fails.

write

protected void write(Writer out,
 char c)
              throws IOException

Write a single character to the output Writer.

Parameters:

out - The Writer to write to.

c - The char to write.

Throws:

IOException - if the Writer fails.

attributeEscapedEntitiesFilter

protected void attributeEscapedEntitiesFilter(Writer out,
 FormatStack fstack,
 String value)
                                       throws IOException

This will take the three pre-defined entities in XML 1.0 ('<', '>', and '&' - used specifically in XML elements) as well as CR/NL and Quote characters which require escaping inside Attribute values and convert their character representation to the appropriate entity reference suitable for XML attribute content. Further, some special characters (e.g. characters that are not valid in the current encoding) are converted to escaped representations.

Note: If FormatStack.getEscapeOutput() is false then no escaping will happen.

Parameters:

out - The destination Writer

fstack - The FormatStack

value - String Attribute value to escape.

Throws:

IOException - if the destination Writer fails.

IllegalDataException - if an entity can not be escaped

textRaw

protected void textRaw(Writer out,
 String str)
                throws IOException

Convenience method that simply passes the input str to write(Writer, String). This could be useful for subclasses to hook in to. All text-type output will come through this or the textRaw(Writer, char) method.

Parameters:

out - the destination writer.

str - the String to write.

Throws:

IOException - if the Writer fails.

textRaw

protected void textRaw(Writer out,
 char ch)
                throws IOException

Convenience method that simply passes the input char to write(Writer, char). This could be useful for subclasses to hook in to. All text-type output will come through this or the textRaw(Writer, String) method.

Parameters:

out - the destination Writer.

ch - the char to write.

Throws:

IOException - if the Writer fails.

textEntityRef

protected void textEntityRef(Writer out,
 String name)
                      throws IOException

Write an EntityRef to the destination.

Parameters:

out - the destination Writer.

name - the EntityRef's name.

Throws:

IOException - if the Writer fails.

textCDATA

protected void textCDATA(Writer out,
 String text)
                  throws IOException

Write a CDATA to the destination

Parameters:

out - the destination Writer

text - the CDATA text

Throws:

IOException - if the Writer fails.

printDocument

protected void printDocument(Writer out,
 FormatStack fstack,
 NamespaceStack nstack,
 Document doc)
                      throws IOException

This will handle printing of a Document.

Parameters:

out - Writer to use.

fstack - the FormatStack

nstack - the NamespaceStack

doc - Document to write.

Throws:

IOException - if the destination Writer fails

printDeclaration

protected void printDeclaration(Writer out,
 FormatStack fstack)
                         throws IOException

This will handle printing of the XML declaration. Assumes XML version 1.0 since we don't directly know.

Parameters:

out - Writer to use.

fstack - the FormatStack

Throws:

IOException - if the destination Writer fails

printDocType

protected void printDocType(Writer out,
 FormatStack fstack,
 DocType docType)
                     throws IOException

This will handle printing of a DocType.

Parameters:

out - Writer to use.

fstack - the FormatStack

docType - DocType to write.

Throws:

IOException - if the destination Writer fails

printProcessingInstruction

protected void printProcessingInstruction(Writer out,
 FormatStack fstack,
 ProcessingInstruction pi)
                                   throws IOException

This will handle printing of a ProcessingInstruction.

Parameters:

out - Writer to use.

fstack - the FormatStack

pi - ProcessingInstruction to write.

Throws:

IOException - if the destination Writer fails

printComment

protected void printComment(Writer out,
 FormatStack fstack,
 Comment comment)
                     throws IOException

This will handle printing of a Comment.

Parameters:

out - Writer to use.

fstack - the FormatStack

comment - Comment to write.

Throws:

IOException - if the destination Writer fails

printEntityRef

protected void printEntityRef(Writer out,
 FormatStack fstack,
 EntityRef entity)
                       throws IOException

This will handle printing of an EntityRef.

Parameters:

out - Writer to use.

fstack - the FormatStack

entity - EntotyRef to write.

Throws:

IOException - if the destination Writer fails

printCDATA

protected void printCDATA(Writer out,
 FormatStack fstack,
 CDATA cdata)
                   throws IOException

This will handle printing of a CDATA.

Parameters:

out - Writer to use.

fstack - the FormatStack

cdata - CDATA to write.

Throws:

IOException - if the destination Writer fails

printText

protected void printText(Writer out,
 FormatStack fstack,
 Text text)
                  throws IOException

This will handle printing of a Text.

Parameters:

out - Writer to use.

fstack - the FormatStack

text - Text to write.

Throws:

IOException - if the destination Writer fails

printElement

protected void printElement(Writer out,
 FormatStack fstack,
 NamespaceStack nstack,
 Element element)
                     throws IOException

This will handle printing of an Element.

This method arranges for outputting the Element infrastructure including Namespace Declarations and Attributes.

Parameters:

out - Writer to use.

fstack - the FormatStack

nstack - the NamespaceStack

element - Element to write.

Throws:

IOException - if the destination Writer fails

printContent

protected void printContent(Writer out,
 FormatStack fstack,
 NamespaceStack nstack,
 Walker walker)
                     throws IOException

This will handle printing of a List of Content.

The list of Content is basically processed as one of three types of content

1. Consecutive text-type (Text, CDATA, and EntityRef) content
2. Stand-alone text-type content
3. Non-text-type content.

Although the code looks complex, the theory is conceptually simple:

1. identify one of the three types (consecutive, stand-alone, non-text)
2. do indent if any is specified.
3. send the type to the respective print* handler (e.g. printCDATA(Writer, FormatStack, CDATA), or printComment(Writer, FormatStack, Comment),
4. do a newline if one is specified.
5. loop back to 1. until there's no more content to process.

Parameters:

out - Writer to use.

fstack - the FormatStack

nstack - the NamespaceStack

walker - Walker of Content to write.

Throws:

IOException - if the destination Writer fails

printNamespace

protected void printNamespace(Writer out,
 FormatStack fstack,
 Namespace ns)
                       throws IOException

This will handle printing of any needed Namespace declarations.

Parameters:

out - Writer to use.

fstack - The current FormatStack

ns - Namespace to print definition of

Throws:

IOException - if the output fails

printAttribute

protected void printAttribute(Writer out,
 FormatStack fstack,
 Attribute attribute)
                       throws IOException

This will handle printing of an Attribute.

Parameters:

out - Writer to use.

fstack - The current FormatStack

attribute - Attribute to output

Throws:

IOException - if the output fails