org.springframework.util
Class CollectionUtils

java.lang.Object
  org.springframework.util.CollectionUtils

public abstract class CollectionUtils
extends Object

Miscellaneous collection utility methods. Mainly for internal use within the framework.

Since:

1.1.3

Author:

Juergen Hoeller, Rob Harrop

Constructor Summary

CollectionUtils()

Method Summary

static Object	findValueOfType(Collection coll, Class type) Find a value of the given type in the given collection.
static Object	findValueOfType(Collection coll, Class[] types) Find a value of one of the given types in the given collection: searching the collection for a value of the first type, then searching for a value of the second type, etc.
static boolean	hasUniqueObject(Collection coll) Determine whether the given collection only contains a single unique object.
static boolean	isEmpty(Collection collection) Return true if the supplied Collection is null or empty.
static boolean	isEmpty(Map map) Return true if the supplied Map is null or empty.

Methods inherited from class java.lang.Object

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

Constructor Detail

CollectionUtils

public CollectionUtils()

Method Detail

isEmpty

public static boolean isEmpty(Collection collection)

Return true if the supplied Collection is null or empty. Otherwise, return false.

Parameters:

collection - the Collection to check

isEmpty

public static boolean isEmpty(Map map)

Return true if the supplied Map is null or empty. Otherwise, return false.

Parameters:

map - the Map to check

hasUniqueObject

public static boolean hasUniqueObject(Collection coll)

Determine whether the given collection only contains a single unique object.

Parameters:

coll - the collection to check

Returns:

true if the collection contains a single reference or multiple references to the same instance, false else

findValueOfType

public static Object findValueOfType(Collection coll,
                                     Class type)
                              throws IllegalArgumentException

Find a value of the given type in the given collection.

Parameters:

coll - the collection to search

type - the type to look for

Returns:

a value of the given type found, or null if none

Throws:

IllegalArgumentException - if more than one value of the given type found

findValueOfType

public static Object findValueOfType(Collection coll,
                                     Class[] types)
                              throws IllegalArgumentException

Find a value of one of the given types in the given collection: searching the collection for a value of the first type, then searching for a value of the second type, etc.

Parameters:

coll - the collection to search

types - the types to look for, in prioritized order

Returns:

a of one of the given types found, or null if none

Throws:

IllegalArgumentException - if more than one value of the given type found