org.archive.crawler.util
Class Transform<Original,Transformed>

java.lang.Object
  java.util.AbstractCollection<Transformed>
      org.archive.crawler.util.Transform<Original,Transformed>

Type Parameters:

Original - the type of the original elements in the collection

Transformed - the type of the tranformed elements

All Implemented Interfaces:

java.lang.Iterable<Transformed>, java.util.Collection<Transformed>

public class Transform<Original,Transformed>
extends java.util.AbstractCollection<Transformed>

A transformation of a collection. The elements in the transform are based on the elements of some other collection; the original collection's elements are transformed using a specified transformer. Changes to the original collection are automatically reflected in the transform and vice-versa.

If the transformer returns null for a given original object, then that object will not be included in the transform. Thus the transform might be smaller than the original collection. Note that Transform instances can never contain the null element.

This collection implementation does not support the optional add operation.

Author:

pjack

Constructor Summary

Transform(java.util.Collection<? extends Original> delegate, Transformer<Original,Transformed> transformer)
Constructor.

Method Summary

java.util.Iterator<Transformed>	iterator()
int	size()
static <Target> java.util.Collection<Target>	subclasses(java.util.Collection<? extends java.lang.Object> c, java.lang.Class<Target> cls) Returns a transform containing only objects of a given class.

Methods inherited from class java.util.AbstractCollection

add, addAll, clear, contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Collection

equals, hashCode

Constructor Detail

Transform

public Transform(java.util.Collection<? extends Original> delegate,
                 Transformer<Original,Transformed> transformer)

Constructor.

Parameters:

delegate - The collection whose elements to transform.

transformer - Transforms the elements

Method Detail

size

public int size()

Specified by:

size in interface java.util.Collection<Transformed>

Specified by:

size in class java.util.AbstractCollection<Transformed>

iterator

public java.util.Iterator<Transformed> iterator()

Specified by:

iterator in interface java.lang.Iterable<Transformed>

Specified by:

iterator in interface java.util.Collection<Transformed>

Specified by:

iterator in class java.util.AbstractCollection<Transformed>

subclasses

public static <Target> java.util.Collection<Target> subclasses(java.util.Collection<? extends java.lang.Object> c,
                                                               java.lang.Class<Target> cls)

Returns a transform containing only objects of a given class.

Type Parameters:

Target - the target class

Parameters:

c - the collection to transform

cls - the class of objects to return

Returns:

a collection containing only objects of class cls