## org.apache.tools.ant.util
Class CollectionUtils

    java.lang.Object
      org.apache.tools.ant.util.CollectionUtils

    public class CollectionUtils

extends java.lang.Object

A set of helper methods related to collection manipulation.

Since:
  Ant 1.5

Nested Class Summary
`static class` `CollectionUtils.EmptyEnumeration<E>` An empty enumeration.

Field Summary
`static java.util.List` `EMPTY_LIST` Deprecated.

Constructor Summary
`CollectionUtils()`

Method Summary

`static

`<E> java.util.Enumeration<E>`

`

`append(java.util.Enumeration<E> e1, java.util.Enumeration<E> e2)`
Append one enumeration to another.

`static

`<T> java.util.Collection<T>`

`

`asCollection(java.util.Iterator<? extends T> iter)`
Returns a collection containing all elements of the iterator.

`static

`<E> java.util.Enumeration<E>`

`

`asEnumeration(java.util.Iterator<E> iter)`
Adapt the specified Iterator to the Enumeration interface.

`static

`<E> java.util.Iterator<E>`

`

`asIterator(java.util.Enumeration<E> e)`
Adapt the specified Enumeration to the Iterator interface.

`static boolean` `equals(java.util.Dictionary<?,?> d1, java.util.Dictionary<?,?> d2)` Deprecated. since 1.6.x.
`static boolean` `equals(java.util.Vector<?> v1, java.util.Vector<?> v2)` Deprecated. since 1.6.x.
`static java.lang.String` `flattenToString(java.util.Collection<?> c)` Creates a comma separated list of all values held in the given collection.
`static int` `frequency(java.util.Collection<?> c, java.lang.Object o)` Counts how often the given Object occurs in the given collection using equals() for comparison.

`static

`<K,V> void`

`

`putAll(java.util.Dictionary<? super K,? super V> m1, java.util.Dictionary<? extends K,? extends V> m2)`
Deprecated. since 1.6.x.

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

Field Detail

### EMPTY_LIST

    @Deprecated
    public static final java.util.List EMPTY_LIST

  Deprecated.
  Collections.emptyList() is Java5+.

Constructor Detail

### CollectionUtils

    public CollectionUtils()

Method Detail

### equals

    public static boolean equals(java.util.Vector<?> v1,
                                 java.util.Vector<?> v2)

  Deprecated. since 1.6.x.

  Please use Vector.equals() or List.equals().

  Parameters:
    `v1` - the first vector.
    `v2` - the second vector.
  Returns:
    true if the vectors are equal.
  Since:
    Ant 1.5

### equals

    public static boolean equals(java.util.Dictionary<?,?> d1,
                                 java.util.Dictionary<?,?> d2)

  Deprecated. since 1.6.x.

  Dictionary does not have an equals. Please use Map.equals().

  Follows the equals contract of Java 2's Map.

  Parameters:
    `d1` - the first directory.
    `d2` - the second directory.
  Returns:
    true if the directories are equal.
  Since:
    Ant 1.5

### flattenToString

    public static java.lang.String flattenToString(java.util.Collection<?> c)

  Creates a comma separated list of all values held in the given collection.

  Since:
    Ant 1.8.0

### putAll

    public static <K,V> void putAll(java.util.Dictionary<? super K,? super V> m1,
                                    java.util.Dictionary<? extends K,? extends V> m2)

  Deprecated. since 1.6.x.

  Dictionary does not know the putAll method. Please use Map.putAll().

  Parameters:
    `m1` - the to directory.
    `m2` - the from directory.
  Since:
    Ant 1.6

### append

    public static <E> java.util.Enumeration<E> append(java.util.Enumeration<E> e1,
                                                      java.util.Enumeration<E> e2)

  Append one enumeration to another. Elements are evaluated lazily.

  Parameters:
    `e1` - the first enumeration.
    `e2` - the subsequent enumeration.
  Returns:
    an enumeration representing e1 followed by e2.
  Since:
    Ant 1.6.3

### asEnumeration

    public static <E> java.util.Enumeration<E> asEnumeration(java.util.Iterator<E> iter)

  Adapt the specified Iterator to the Enumeration interface.

  Parameters:
    `iter` - the Iterator to adapt.
  Returns:
    an Enumeration.

### asIterator

    public static <E> java.util.Iterator<E> asIterator(java.util.Enumeration<E> e)

  Adapt the specified Enumeration to the Iterator interface.

  Parameters:
    `e` - the Enumeration to adapt.
  Returns:
    an Iterator.

### asCollection

    public static <T> java.util.Collection<T> asCollection(java.util.Iterator<? extends T> iter)

  Returns a collection containing all elements of the iterator.

  Since:
    Ant 1.8.0

### frequency

    public static int frequency(java.util.Collection<?> c,
                                java.lang.Object o)

  Counts how often the given Object occurs in the given collection using equals() for comparison.

  Since:
    Ant 1.8.0