org.apache.commons.collections.iterators

## Class TransformIterator

- java.lang.Object
- - org.apache.commons.collections.iterators.TransformIterator

- All Implemented Interfaces:
    Iterator

      public class TransformIterator
      extends Object
      implements Iterator

  Decorates an iterator such that each element returned is transformed.
  Since:
    Commons Collections 1.0
  Version:
    $Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
  Author:
    James Strachan, Stephen Colebourne

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `TransformIterator()` Constructs a new `TransformIterator` that will not function until the `setIterator` method is invoked.
    `TransformIterator(Iterator iterator)` Constructs a new `TransformIterator` that won't transform elements from the given iterator.
    `TransformIterator(Iterator iterator, Transformer transformer)` Constructs a new `TransformIterator` that will use the given iterator and transformer.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `Iterator` | `getIterator()` Gets the iterator this iterator is using.
    `Transformer` | `getTransformer()` Gets the transformer this iterator is using.
    `boolean` | `hasNext()`
    `Object` | `next()` Gets the next object from the iteration, transforming it using the current transformer.
    `void` | `remove()`
    `void` | `setIterator(Iterator iterator)` Sets the iterator for this iterator to use.
    `void` | `setTransformer(Transformer transformer)` Sets the transformer this the iterator to use.
    `protected Object` | `transform(Object source)` Transforms the given object using the transformer.

    - ### Methods inherited from class java.lang.Object

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

- - ### Constructor Detail

    - #### TransformIterator

          public TransformIterator()

      Constructs a new `TransformIterator` that will not function until the `setIterator` method is invoked.

    - #### TransformIterator

          public TransformIterator(Iterator iterator)

      Constructs a new `TransformIterator` that won't transform elements from the given iterator.
      Parameters:
        `iterator` - the iterator to use

    - #### TransformIterator

          public TransformIterator(Iterator iterator,
                           Transformer transformer)

      Constructs a new `TransformIterator` that will use the given iterator and transformer. If the given transformer is null, then objects will not be transformed.
      Parameters:
        `iterator` - the iterator to use
        `transformer` - the transformer to use

  - ### Method Detail

    - #### hasNext

          public boolean hasNext()

      Specified by:
        `hasNext` in interface `Iterator`

    - #### next

          public Object next()

      Gets the next object from the iteration, transforming it using the current transformer. If the transformer is null, no transformation occurs and the object from the iterator is returned directly.
      Specified by:
        `next` in interface `Iterator`
      Returns:
        the next object
      Throws:
        `NoSuchElementException` - if there are no more elements

    - #### remove

          public void remove()

      Specified by:
        `remove` in interface `Iterator`

    - #### getIterator

          public Iterator getIterator()

      Gets the iterator this iterator is using.
      Returns:
        the iterator.

    - #### setIterator

          public void setIterator(Iterator iterator)

      Sets the iterator for this iterator to use. If iteration has started, this effectively resets the iterator.
      Parameters:
        `iterator` - the iterator to use

    - #### getTransformer

          public Transformer getTransformer()

      Gets the transformer this iterator is using.
      Returns:
        the transformer.

    - #### setTransformer

          public void setTransformer(Transformer transformer)

      Sets the transformer this the iterator to use. A null transformer is a no-op transformer.
      Parameters:
        `transformer` - the transformer to use

    - #### transform

          protected Object transform(Object source)

      Transforms the given object using the transformer. If the transformer is null, the original object is returned as-is.
      Parameters:
        `source` - the object to transform
      Returns:
        the transformed object

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