Package net.sourceforge.pmd.util

Class CollectionUtil

java.lang.Object

net.sourceforge.pmd.util.CollectionUtil

public final class CollectionUtil
extends java.lang.Object

Generic collection and array-related utility functions for java.util types. See ClassUtil for comparable facilities for short name lookup.

Version:

$Revision$

Author:

Brian Remedios

Field Summary

Fields

Modifier and Type	Field	Description
static TypeMap	COLLECTION_CLASSES_BY_NAMES
static TypeMap	COLLECTION_INTERFACES_BY_NAMES

Method Summary

Modifier and Type	Method	Description
static <T> int	addWithoutDuplicates(java.util.Collection<T> source, java.util.Collection<T> target)	Add elements from the source to the target as long as they don't already exist there.
static <T> T[]	addWithoutDuplicates(T[] values, T newValue)	Deprecated.
static <T> T[]	addWithoutDuplicates(T[] values, T[] newValues)	Deprecated.
static boolean	areEqual(java.lang.Object value, java.lang.Object otherValue)	Deprecated. Objects.deepEquals(Object, Object)
static <T> boolean	areSemanticEquals(T[] a, T[] b)	Deprecated. Arrays.deepEquals(Object[], Object[])
static boolean	arraysAreEqual(java.lang.Object value, java.lang.Object otherValue)	Deprecated. Objects.deepEquals(Object, Object)
static <T> java.util.Set<T>	asSet(T[] items)	Returns the items as a populated set.
static java.lang.Class<?>	getCollectionTypeFor(java.lang.String shortName)	Returns the collection type if we recognize it by its short name.
static <K,V> java.util.Map<V,K>	invertedMapFrom(java.util.Map<K,V> source)	Returns a map based on the source but with the key & values swapped.
static boolean	isCollectionType(java.lang.Class<?> clazzType, boolean includeInterfaces)	Return whether we can identify the typeName as a java.util collection class or interface as specified.
static boolean	isCollectionType(java.lang.String typeName, boolean includeInterfaces)	Return whether we can identify the typeName as a java.util collection class or interface as specified.
static boolean	isEmpty(java.lang.Object[] items)	Returns whether the items array is null or has zero length.
static boolean	isNotEmpty(java.lang.Object[] items)	Returns whether the items array is non-null and has at least one entry.
static <K,V> java.util.Map<K,V>	mapFrom(K[] keys, V[] values)	Creates and returns a map populated with the keyValuesSets where the value held by the tuples are they key and value in that order.
static <T> java.util.List<T>	toList(java.util.Iterator<T> it)	Consumes all the elements of the iterator and returns a list containing them.
static boolean	valuesAreTransitivelyEqual(java.lang.Object[] thisArray, java.lang.Object[] thatArray)	Deprecated. Arrays.deepEquals(Object[], Object[])

Methods inherited from class java.lang.Object

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

Field Detail

COLLECTION_INTERFACES_BY_NAMES

public static final TypeMap COLLECTION_INTERFACES_BY_NAMES

COLLECTION_CLASSES_BY_NAMES

public static final TypeMap COLLECTION_CLASSES_BY_NAMES

Method Detail

addWithoutDuplicates

public static <T> int addWithoutDuplicates(java.util.Collection<T> source,
                                           java.util.Collection<T> target)

Add elements from the source to the target as long as they don't already exist there. Return the number of items actually added.

Parameters:

source -

target -

Returns:

int

getCollectionTypeFor

public static java.lang.Class<?> getCollectionTypeFor(java.lang.String shortName)

Returns the collection type if we recognize it by its short name.

Parameters:

shortName - String

Returns:

Class

isCollectionType

public static boolean isCollectionType(java.lang.String typeName,
                                       boolean includeInterfaces)

Return whether we can identify the typeName as a java.util collection class or interface as specified.

Parameters:

typeName - String

includeInterfaces - boolean

Returns:

boolean

isCollectionType

public static boolean isCollectionType(java.lang.Class<?> clazzType,
                                       boolean includeInterfaces)

Return whether we can identify the typeName as a java.util collection class or interface as specified.

Parameters:

clazzType - Class

includeInterfaces - boolean

Returns:

boolean

asSet

public static <T> java.util.Set<T> asSet(T[] items)

Returns the items as a populated set.

Parameters:

items - Object[]

Returns:

Set

mapFrom

public static <K,V> java.util.Map<K,V> mapFrom(K[] keys,
                                               V[] values)

Creates and returns a map populated with the keyValuesSets where the value held by the tuples are they key and value in that order.

Parameters:

keys - K[]

values - V[]

Returns:

Map

invertedMapFrom

public static <K,V> java.util.Map<V,K> invertedMapFrom(java.util.Map<K,V> source)

Returns a map based on the source but with the key & values swapped.

Parameters:

source - Map

Returns:

Map

toList

public static <T> java.util.List<T> toList(java.util.Iterator<T> it)

Consumes all the elements of the iterator and returns a list containing them. The iterator is then unusable

Parameters:

it - An iterator

Returns:

a list containing the elements remaining on the iterator

arraysAreEqual

@Deprecated
public static boolean arraysAreEqual(java.lang.Object value,
                                     java.lang.Object otherValue)

Deprecated.

Objects.deepEquals(Object, Object)

Returns true if the objects are array instances and each of their elements compares via equals as well.

Parameters:

value - Object

otherValue - Object

Returns:

boolean

valuesAreTransitivelyEqual

@Deprecated
public static boolean valuesAreTransitivelyEqual(java.lang.Object[] thisArray,
                                                 java.lang.Object[] thatArray)

Deprecated.

Arrays.deepEquals(Object[], Object[])

Returns whether the arrays are equal by examining each of their elements, even if they are arrays themselves.

Parameters:

thisArray - Object[]

thatArray - Object[]

Returns:

boolean

areEqual

@Deprecated
public static boolean areEqual(java.lang.Object value,
                               java.lang.Object otherValue)

Deprecated.

Objects.deepEquals(Object, Object)

A comprehensive isEqual method that handles nulls and arrays safely.

Parameters:

value - Object

otherValue - Object

Returns:

boolean

isEmpty

public static boolean isEmpty(java.lang.Object[] items)

Returns whether the items array is null or has zero length.

Parameters:

items -

Returns:

boolean

isNotEmpty

public static boolean isNotEmpty(java.lang.Object[] items)

Returns whether the items array is non-null and has at least one entry.

Parameters:

items -

Returns:

boolean

areSemanticEquals

@Deprecated
public static <T> boolean areSemanticEquals(T[] a,
                                            T[] b)

Deprecated.

Arrays.deepEquals(Object[], Object[])

Returns true if both arrays are if both are null or have zero-length, otherwise return the false if their respective elements are not equal by position.

Type Parameters:

T -

Parameters:

a -

b -

Returns:

boolean

addWithoutDuplicates

@Deprecated
public static <T> T[] addWithoutDuplicates(T[] values,
                                           T newValue)

Deprecated.

If the newValue is already held within the values array then the values array is returned, otherwise a new array is created appending the newValue to the end.

Type Parameters:

T -

Parameters:

values -

newValue -

Returns:

an array containing the union of values and newValue

addWithoutDuplicates

@Deprecated
public static <T> T[] addWithoutDuplicates(T[] values,
                                           T[] newValues)

Deprecated.

Returns an array of values as a union set of the two input arrays.

Type Parameters:

T -

Parameters:

values -

newValues -

Returns:

the union of the two arrays