org.cip4.jdflib.util

Class ContainerUtil

java.lang.Object

org.cip4.jdflib.util.ContainerUtil

public class ContainerUtil
extends Object

class with utilities for containers, e.g. Vectors, sets etc.
also simple object utilities

Author:

Dr. Rainer Prosi, Heidelberger Druckmaschinen AG before June 18, 2009

Constructor Summary

Constructors

Constructor and Description
ContainerUtil()

Method Summary

Methods

Modifier and Type	Method and Description
static <a> Collection<a>	addAll(Collection<a> c1, Collection<a> c2) null safe addAll
static int	compare(Comparable c0, Comparable c1) static implementation of compare for any comparable object that gracefully handles null null is always the smallest
static <a> void	ensureSize(int size, Collection<a> coll) ensure that a collection has at least size elements and fill any newly created entries with nulls
static boolean	equals(Object a, Object b) return true if a equals b or both are null
static <a,b> VectorMap<b,a>	getInvertedMap(Map<a,b> m) create an inverted map with keys and values swapped. The new values are vectors since a map may have identical values for different keys
static <a> Vector<a>	getKeyVector(Map<a,?> m) create a Vector of key values from a map
static <a> IMatches	getMatch(Collection<? extends IMatches> c, a obj, int iSkip) return a matching element from a collection of IMatches
static <a> Vector<IMatches>	getMatches(Collection<? extends IMatches> c, a obj) return a matching element from a collection of IMatches
static boolean	matches(IMatches a, Object b) return true if a matches b or both are null
static boolean	matchesExisting(IMatches a, Object b) return true if a matches b or one of a or b is null
static <a> Set<a>	toHashSet(a[] l) create a HashSet from an Array
static <a> Set<a>	toHashSet(Enumeration<a> enumeration) create a HashSet from an enumeration
static <a> Set<a>	toHashSet(List<a> list) create a HashSet from a List (Vector...)
static <a,b> Vector<b>	toValueVector(Map<a,b> m) create a Vector copy of entry values from a map
static <a extends Comparable<? super a>,b> Vector<b>	toValueVector(Map<a,b> m, boolean sortByKey) create a Vector of entry values from a map
static <a> Vector<a>	toVector(a[] array) create a Vector from an Array, skipping null elements
static <a> Collection<a>	unify(Collection<a> c) unify a collection while retaining the initial order (if the input collection is ordered)

Methods inherited from class java.lang.Object

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

Constructor Detail

ContainerUtil

public ContainerUtil()

Method Detail

toHashSet

public static <a> Set<a> toHashSet(Enumeration<a> enumeration)

create a HashSet from an enumeration

Type Parameters:

a - the data type of the sets

Parameters:

enumeration - the enumeration

Returns:

a Set created from list

toHashSet

public static <a> Set<a> toHashSet(List<a> list)

create a HashSet from a List (Vector...)

Type Parameters:

a - the data type of the sets

Parameters:

list - the list

Returns:

a Set created from list

toHashSet

public static <a> Set<a> toHashSet(a[] l)

create a HashSet from an Array

Type Parameters:

a - datatype

Parameters:

l - the array

Returns:

a Set created from list

toVector

public static <a> Vector<a> toVector(a[] array)

create a Vector from an Array, skipping null elements

Type Parameters:

a - the type

Parameters:

array - the array to convert

Returns:

a Vector

addAll

public static <a> Collection<a> addAll(Collection<a> c1,
                       Collection<a> c2)

null safe addAll

Type Parameters:

a - type

Parameters:

c1 - first collection

c2 - second collection

Returns:

c1 with c2 added, c2 if c1==null

getMatch

public static <a> IMatches getMatch(Collection<? extends IMatches> c,
                    a obj,
                    int iSkip)

return a matching element from a collection of IMatches

Type Parameters:

a - the data type

Parameters:

c - the collection to search

obj - the search key for matches

iSkip - which one to grab, may be negative in which case we count -1=last, -2=second last...

Returns:

the matching

getMatches

public static <a> Vector<IMatches> getMatches(Collection<? extends IMatches> c,
                              a obj)

return a matching element from a collection of IMatches

Type Parameters:

a - the data type

Parameters:

c - the collection to search

obj - the search key for matches

Returns:

Vector of matching a

toValueVector

public static <a extends Comparable<? super a>,b> Vector<b> toValueVector(Map<a,b> m,
                                                          boolean sortByKey)

create a Vector of entry values from a map

Type Parameters:

a - type of the map key

b - type of the map entry

Parameters:

m - the map to dump to an array

sortByKey - , if true, sort the entries by key

Returns:

the vector

toValueVector

public static <a,b> Vector<b> toValueVector(Map<a,b> m)

create a Vector copy of entry values from a map

Type Parameters:

a - data type of the map key

b - data type of the map value

Parameters:

m - the map to dump to an array

Returns:

the vector

getInvertedMap

public static <a,b> VectorMap<b,a> getInvertedMap(Map<a,b> m)

create an inverted map with keys and values swapped.
The new values are vectors since a map may have identical values for different keys

Type Parameters:

a - data type of the map key

b - data type of the map value

Parameters:

m - the map to invert

Returns:

the inverted map

getKeyVector

public static <a> Vector<a> getKeyVector(Map<a,?> m)

create a Vector of key values from a map

Type Parameters:

a - data type of the map key

Parameters:

m - the map to dump to an array

Returns:

the vector of keys - note that this Vector goes NOT reflect changes to the map

equals

public static boolean equals(Object a,
             Object b)

return true if a equals b or both are null

Parameters:

a - Object to compare

b - Object to compare

Returns:

boolean true if a equals b or both are null

matches

public static boolean matches(IMatches a,
              Object b)

return true if a matches b or both are null

Parameters:

a - Object to compare

b - Object to compare

Returns:

boolean true if a matches b or both are null

matchesExisting

public static boolean matchesExisting(IMatches a,
                      Object b)

return true if a matches b or one of a or b is null

Parameters:

a - Object to compare

b - Object to compare

Returns:

boolean true if a matches b or both are null

compare

public static int compare(Comparable c0,
          Comparable c1)

static implementation of compare for any comparable object that gracefully handles null
null is always the smallest

Parameters:

c0 -

c1 -

Returns:

-1 if c0 < c1, 0 if equal, 1 if c0 > c1;

ensureSize

public static <a> void ensureSize(int size,
                  Collection<a> coll)

ensure that a collection has at least size elements and fill any newly created entries with nulls

Type Parameters:

a - anything - needed for the cast

Parameters:

size -

coll -

unify

public static <a> Collection<a> unify(Collection<a> c)

unify a collection while retaining the initial order (if the input collection is ordered)

Type Parameters:

a - the data type of the collection

Parameters:

c - the collection to unify

Returns:

the unified collection - always the input collection