## org.apache.taglibs.standard.tag.common.core
Class ForEachSupport

    java.lang.Object
      javax.servlet.jsp.tagext.TagSupport
          javax.servlet.jsp.jstl.core.LoopTagSupport
              org.apache.taglibs.standard.tag.common.core.ForEachSupport

All Implemented Interfaces:
  Serializable, LoopTag, IterationTag, JspTag, Tag, TryCatchFinally

Direct Known Subclasses:
  ForEachTag, ForEachTag

    public abstract class ForEachSupport

extends LoopTagSupport

Support for tag handlers for <forEach>, the core iteration tag in JSTL 1.0. This class extends LoopTagSupport and provides ForEach-specific functionality. The rtexprvalue library and the expression-evaluating library each have handlers that extend this class.

Localized here is the logic for handling the veritable smorgasbord of types supported by <forEach>, including arrays, Collections, and others. To see how the actual iteration is controlled, review the javax.servlet.jsp.jstl.core.LoopTagSupport class instead.

Author:
  Shawn Bayern
See Also:
  `LoopTagSupport`, Serialized Form

Nested Class Summary
`protected static interface` `ForEachSupport.ForEachIterator`
`protected class` `ForEachSupport.SimpleForEachIterator`

Field Summary
`protected ForEachSupport.ForEachIterator` `items`
`protected Object` `rawItems`

Fields inherited from class javax.servlet.jsp.jstl.core.LoopTagSupport
`begin, beginSpecified, deferredExpression, end, endSpecified, itemId, statusId, step, stepSpecified`

Fields inherited from class javax.servlet.jsp.tagext.TagSupport
`id, pageContext`

Fields inherited from interface javax.servlet.jsp.tagext.Tag
`EVAL_BODY_INCLUDE, EVAL_PAGE, SKIP_BODY, SKIP_PAGE`

Fields inherited from interface javax.servlet.jsp.tagext.IterationTag
`EVAL_BODY_AGAIN`

Fields inherited from interface javax.servlet.jsp.tagext.Tag
`EVAL_BODY_INCLUDE, EVAL_PAGE, SKIP_BODY, SKIP_PAGE`

Constructor Summary
`ForEachSupport()`

Method Summary
`protected boolean` `hasNext()` Returns information concerning the availability of more items over which to iterate.
`protected Object` `next()` Returns the next object over which the tag should iterate.
`protected void` `prepare()` Prepares for a single tag invocation.
`void` `release()` Releases any resources this LoopTagSupport may have (or inherit).
`protected ForEachSupport.ForEachIterator` `supportedTypeForEachIterator(Object o)`
`protected ForEachSupport.ForEachIterator` `toForEachIterator(boolean[] a)`
`protected ForEachSupport.ForEachIterator` `toForEachIterator(byte[] a)`
`protected ForEachSupport.ForEachIterator` `toForEachIterator(char[] a)`
`protected ForEachSupport.ForEachIterator` `toForEachIterator(Collection c)`
`protected ForEachSupport.ForEachIterator` `toForEachIterator(double[] a)`
`protected ForEachSupport.ForEachIterator` `toForEachIterator(Enumeration e)`
`protected ForEachSupport.ForEachIterator` `toForEachIterator(float[] a)`
`protected ForEachSupport.ForEachIterator` `toForEachIterator(int[] a)`
`protected ForEachSupport.ForEachIterator` `toForEachIterator(Iterator i)`
`protected ForEachSupport.ForEachIterator` `toForEachIterator(long[] a)`
`protected ForEachSupport.ForEachIterator` `toForEachIterator(Map m)`
`protected ForEachSupport.ForEachIterator` `toForEachIterator(Object o)`
`protected ForEachSupport.ForEachIterator` `toForEachIterator(Object[] a)`
`protected ForEachSupport.ForEachIterator` `toForEachIterator(short[] a)`
`protected ForEachSupport.ForEachIterator` `toForEachIterator(String s)`

Methods inherited from class javax.servlet.jsp.jstl.core.LoopTagSupport
`doAfterBody, doCatch, doFinally, doStartTag, getCurrent, getDelims, getLoopStatus, setVar, setVarStatus, validateBegin, validateEnd, validateStep`

Methods inherited from class javax.servlet.jsp.tagext.TagSupport
`doEndTag, findAncestorWithClass, getId, getParent, getValue, getValues, removeValue, setId, setPageContext, setParent, setValue`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Methods inherited from interface javax.servlet.jsp.tagext.Tag
`doEndTag, getParent, setPageContext, setParent`

Methods inherited from interface javax.servlet.jsp.tagext.Tag
`doEndTag, getParent, setPageContext, setParent`

Field Detail

### items

    protected ForEachSupport.ForEachIterator items

### rawItems

    protected Object rawItems

Constructor Detail

### ForEachSupport

    public ForEachSupport()

Method Detail

### hasNext

    protected boolean hasNext()
                       throws JspTagException

  Description copied from class: `LoopTagSupport`

  Returns information concerning the availability of more items over which to iterate. This method must be provided by concrete subclasses of LoopTagSupport to assist the iterative logic provided by the supporting base class.

  See next for more information about the purpose and expectations behind this tag.

  Specified by:
    `hasNext` in class `LoopTagSupport`
  Returns:
    `true` if there is at least one more item to iterate over, `false` otherwise
  Throws:
    `JspTagException`
  See Also:
    `LoopTagSupport.next()`

### next

    protected Object next()
                   throws JspTagException

  Description copied from class: `LoopTagSupport`

  Returns the next object over which the tag should iterate. This method must be provided by concrete subclasses of LoopTagSupport to inform the base logic about what objects it should iterate over.

  It is expected that this method will generally be backed by an Iterator, but this will not always be the case. In particular, if retrieving the next object raises the possibility of an exception being thrown, this method allows that exception to propagate back to the JSP container as a JspTagException; a standalone Iterator would not be able to do this. (This explains why LoopTagSupport does not simply call for an Iterator from its subtags.)

  Specified by:
    `next` in class `LoopTagSupport`
  Returns:
    the java.lang.Object to use in the next round of iteration
  Throws:
    `JspTagException` - for other, unexpected exceptions

### prepare

    protected void prepare()
                    throws JspTagException

  Description copied from class: `LoopTagSupport`

  Prepares for a single tag invocation. Specifically, allows subclasses to prepare for calls to hasNext() and next(). Subclasses can assume that prepare() will be called once for each invocation of doStartTag() in the superclass.

  Specified by:
    `prepare` in class `LoopTagSupport`
  Throws:
    `JspTagException`

### release

    public void release()

  Description copied from class: `LoopTagSupport`
  Releases any resources this LoopTagSupport may have (or inherit).

  Specified by:
    `release` in interface `Tag`
  Overrides:
    `release` in class `LoopTagSupport`
  See Also:
    `Tag.release()`

### supportedTypeForEachIterator

    protected ForEachSupport.ForEachIterator supportedTypeForEachIterator(Object o)
                                                                   throws JspTagException

  Throws:
    `JspTagException`

### toForEachIterator

    protected ForEachSupport.ForEachIterator toForEachIterator(Object o)
                                                        throws JspTagException

  Throws:
    `JspTagException`

### toForEachIterator

    protected ForEachSupport.ForEachIterator toForEachIterator(Object[] a)

### toForEachIterator

    protected ForEachSupport.ForEachIterator toForEachIterator(boolean[] a)

### toForEachIterator

    protected ForEachSupport.ForEachIterator toForEachIterator(byte[] a)

### toForEachIterator

    protected ForEachSupport.ForEachIterator toForEachIterator(char[] a)

### toForEachIterator

    protected ForEachSupport.ForEachIterator toForEachIterator(short[] a)

### toForEachIterator

    protected ForEachSupport.ForEachIterator toForEachIterator(int[] a)

### toForEachIterator

    protected ForEachSupport.ForEachIterator toForEachIterator(long[] a)

### toForEachIterator

    protected ForEachSupport.ForEachIterator toForEachIterator(float[] a)

### toForEachIterator

    protected ForEachSupport.ForEachIterator toForEachIterator(double[] a)

### toForEachIterator

    protected ForEachSupport.ForEachIterator toForEachIterator(Collection c)

### toForEachIterator

    protected ForEachSupport.ForEachIterator toForEachIterator(Iterator i)

### toForEachIterator

    protected ForEachSupport.ForEachIterator toForEachIterator(Enumeration e)

### toForEachIterator

    protected ForEachSupport.ForEachIterator toForEachIterator(Map m)

### toForEachIterator

    protected ForEachSupport.ForEachIterator toForEachIterator(String s)

Copyright © 2008 Mort Bay Consulting. All Rights Reserved.