Class IteratorTool

java.lang.Object
org.apache.velocity.tools.generic.IteratorTool
All Implemented Interfaces:
Iterator

@DefaultKey("mill") @Deprecated public class IteratorTool extends Object implements Iterator
Deprecated.
Use LoopTool instead

A convenience tool to use with #foreach loops. It wraps a list to let the designer specify a condition to terminate the loop, and reuse the same list in different loops.

Example of use:

  Java
  ----
  context.put("mill", new IteratorTool());


  VTL
  ---

  #set ($list = [1, 2, 3, 5, 8, 13])
  #set ($numbers = $mill.wrap($list))

  #foreach ($item in $numbers)
  #if ($item < 8) $numbers.more()#end
  #end

  $numbers.more()


  Output
  ------

   1 2 3 5
  8

 Example tools.xml config (if you want to use this with VelocityView):
 <tools>
   <toolbox scope="request">
     <tool class="org.apache.velocity.tools.generic.IteratorTool"/>
   </toolbox>
 </tools>
 

Warning: It is not recommended to use hasNext() with this tool as it is used to control the #foreach. Use hasMore() instead.

Version:
$Id: IteratorTool.java 598471 2007-11-27 00:26:10Z nbubna $
Author:
Denis Bredelet
  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private boolean
    Deprecated.
     
    private Iterator
    Deprecated.
     
    protected Object
    Deprecated.
     
    private boolean
    Deprecated.
     
    private Object
    Deprecated.
     
  • Constructor Summary

    Constructors
    Constructor
    Description
    Deprecated.
    Create a IteratorTool instance to use as tool.
    Deprecated.
    Create a IteratorTool instance to use in #foreach.
  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    Deprecated.
    Returns true if there are more elements in the wrapped list.
    boolean
    Deprecated.
    Returns true if there are more elements in the list and more() was called.
    private void
    Deprecated.
    Wraps a list with the tool.
    Deprecated.
    Asks for the next element in the list.
    Deprecated.
    Gets the next object in the list.
    void
    Deprecated.
    Removes the current element from the list.
    void
    Deprecated.
    Resets the wrapper so that it starts over at the beginning of the list.
    void
    Deprecated.
    Puts a condition to break out of the loop.
    Deprecated.
    Returns this object as a String.
    wrap(Object list)
    Deprecated.
    Wraps a list with the tool.

    Methods inherited from class java.lang.Object

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

    Methods inherited from interface java.util.Iterator

    forEachRemaining
  • Field Details

    • wrapped

      private Object wrapped
      Deprecated.
    • iterator

      private Iterator iterator
      Deprecated.
    • wantMore

      private boolean wantMore
      Deprecated.
    • cachedNext

      private boolean cachedNext
      Deprecated.
    • next

      protected Object next
      Deprecated.
  • Constructor Details

    • IteratorTool

      public IteratorTool()
      Deprecated.
      Create a IteratorTool instance to use as tool. When it is created this way, the tool returns a new instance each time wrap() is called. This is useful when you want to allow the designers to create instances.
    • IteratorTool

      public IteratorTool(Object wrapped)
      Deprecated.
      Create a IteratorTool instance to use in #foreach.
      Parameters:
      wrapped - The list to wrap.
  • Method Details

    • wrap

      public IteratorTool wrap(Object list)
      Deprecated.
      Wraps a list with the tool.
      The list can be an array, a Collection, a Map, an Iterator or an Enumeration.
      If the list is a Map, the tool iterates over the values.
      If the list is an Iterator or an Enumeration, the tool can be used only once.
      Parameters:
      list - The list to wrap.
      Returns:
      A new wrapper if this object is used as a tool, or itself if it is a wrapper.
    • internalWrap

      private void internalWrap(Object wrapped)
      Deprecated.
      Wraps a list with the tool. This object can therefore be used instead of the list itself in a #foreach. The list can be an array, a Collection, a Map, an Iterator or an Enumeration.
      - If the list is a Map, the tool iterates over the values.
      - If the list is an Iterator or an Enumeration, the tool can be used only once.
      Parameters:
      wrapped - The list to wrap.
    • reset

      public void reset()
      Deprecated.

      Resets the wrapper so that it starts over at the beginning of the list.

      Note to programmers: This method has no effect if the wrapped object is an enumeration or an iterator.

    • next

      public Object next()
      Deprecated.

      Gets the next object in the list. This method is called by #foreach to define $item in:

       #foreach( $item in $list )
       

      This method is not intended for template designers, but they can use them if they want to read the value of the next item without doing more().

      Specified by:
      next in interface Iterator
      Returns:
      The next item in the list.
      Throws:
      NoSuchElementException - if there are no more elements in the list.
    • hasNext

      public boolean hasNext()
      Deprecated.
      Returns true if there are more elements in the list and more() was called.
      This code always return false:
       tool.hasNext()? tool.hasNext(): false;
       
      Specified by:
      hasNext in interface Iterator
      Returns:
      true if there are more elements, and either more() or hasNext() was called since last call.
    • remove

      public void remove() throws UnsupportedOperationException
      Deprecated.
      Removes the current element from the list. The current element is defined as the last element that was read from the list, either with next() or with more().
      Specified by:
      remove in interface Iterator
      Throws:
      UnsupportedOperationException - if the wrapped list iterator doesn't support this operation.
    • more

      public Object more()
      Deprecated.

      Asks for the next element in the list. This method is to be used by the template designer in #foreach loops.

      If this method is called in the body of #foreach, the loop continues as long as there are elements in the list.
      If this method is not called the loop terminates after the current iteration.

      Returns:
      The next element in the list, or null if there are no more elements.
    • hasMore

      public boolean hasMore()
      Deprecated.
      Returns true if there are more elements in the wrapped list.
      If this object doesn't wrap a list, the method always returns false.
      Returns:
      true if there are more elements in the list.
    • stop

      public void stop()
      Deprecated.
      Puts a condition to break out of the loop. The #foreach loop will terminate after this iteration, unless more() is called after stop().
    • toString

      public String toString()
      Deprecated.
      Returns this object as a String.
      If this object is used as a tool, it just gives the class name.
      Otherwise it appends the wrapped list to the class name.
      Overrides:
      toString in class Object
      Returns:
      A string representation of this object.