Package org.apache.felix.scr.impl.inject.field

Class FieldUtils

  • public class FieldUtils
extends java.lang.Object
    Utility methods for handling field injection.

    • Constructor Summary

      Constructors 
      Constructor Description
      FieldUtils()  

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      private static FieldUtils.FieldSearchResult accept​(java.lang.Class<?> componentClass, java.lang.reflect.Field field, boolean acceptPrivate, boolean acceptPackage, ComponentLogger logger)
      This method checks whether the found field is acceptable (= usable) for the component instance.
      private static FieldUtils.FieldSearchResult getField​(java.lang.Class<?> componentClass, java.lang.Class<?> targetClass, java.lang.String fieldName, boolean acceptPrivate, boolean acceptPackage, ComponentLogger logger)
      Finds the field named fieldName field in the given targetClass.
      static FieldUtils.FieldSearchResult searchField​(java.lang.Class<?> componentClass, java.lang.String fieldName, ComponentLogger logger)
      Searches the field named fieldName in the given targetClass.
      private static void setAccessible​(java.lang.reflect.Field field)
      Make the field accessible
      static void setField​(java.lang.reflect.Field f, java.lang.Object component, java.lang.Object value, ComponentLogger logger)
      Set the field, type etc.
      static java.lang.String toString​(java.lang.Class<?> componentClass, java.lang.reflect.Field field)
      Return a string representation of the field

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • FieldUtils

        public FieldUtils()

    • Method Detail

      • searchField

        public static FieldUtils.FieldSearchResult searchField​(java.lang.Class<?> componentClass,
                                                       java.lang.String fieldName,
                                                       ComponentLogger logger)
        Searches the field named fieldName in the given targetClass. If the target class has no acceptable field the class hierarchy is traversed until a field is found or the root of the class hierarchy is reached without finding a field.

        If an unexpected error occurs while searching, null is returned. In all other cases a FieldSearchResult is returned. If no field is found, FieldSearchResult#field is set to null. If the field is found, but not usable (e.g. due to visibility restrictions), FieldSearchResult#usable is set to false.

        Parameters:
        targetClass - The class of the component
        fieldName - The name of the field
        logger - A logger to log errors / problems
        Returns:
        A field search result or null if an unexpected error occurred.

      • getField

        private static FieldUtils.FieldSearchResult getField​(java.lang.Class<?> componentClass,
                                                     java.lang.Class<?> targetClass,
                                                     java.lang.String fieldName,
                                                     boolean acceptPrivate,
                                                     boolean acceptPackage,
                                                     ComponentLogger logger)
                                              throws java.lang.reflect.InvocationTargetException
        Finds the field named fieldName field in the given targetClass. If the target class has no acceptable field the class hierarchy is traversed until a field is found or the root of the class hierarchy is reached without finding a field.
        Parameters:
        componentClass - The class of the component (for logging)
        targetClass - The class in which to look for the method
        fieldName - The name of the field
        acceptPrivate - true if private fields should be considered.
        acceptPackage - true if package private fields should be considered.
        logger - For error logging
        Returns:
        If the field is found a FieldSearchResult is returned. If the field is not found, null is returned.
        Throws:
        java.lang.reflect.InvocationTargetException - If an unexpected Throwable is caught trying to find the requested field.

      • accept

        private static FieldUtils.FieldSearchResult accept​(java.lang.Class<?> componentClass,
                                                   java.lang.reflect.Field field,
                                                   boolean acceptPrivate,
                                                   boolean acceptPackage,
                                                   ComponentLogger logger)
        This method checks whether the found field is acceptable (= usable) for the component instance. It returns a FieldSearchResult with the usable flag set to true if the field is not static and
        • Is public or protected
        • Is private and acceptPrivate is true
        • Is package private and acceptPackage is true

        If the field is usable, this method makes the field accessible.

        If the field is not usable, a FieldSearchResult with the usable flag set to false is returned and an error is logged with the provided logger.

        Parameters:
        componentClass - The class of the component,.
        field - The field to check
        acceptPrivate - Whether a private field is acceptable
        acceptPackage - Whether a package private field is acceptable
        logger - The logger for error logging
        Returns:
        A field search result, this is never null

      • toString

        public static java.lang.String toString​(java.lang.Class<?> componentClass,
                                        java.lang.reflect.Field field)
        Return a string representation of the field
        Parameters:
        componentClass - The component class
        field - The field
        Returns:
        A string representation of the field

      • setAccessible

        private static void setAccessible​(java.lang.reflect.Field field)
        Make the field accessible
        Parameters:
        field - The field

      • setField

        public static void setField​(java.lang.reflect.Field f,
                            java.lang.Object component,
                            java.lang.Object value,
                            ComponentLogger logger)
        Set the field, type etc.
        Parameters:
        f - The field
        component - The component instance
        value - The value to set
        logger - The logger