net.gdface.utils

类 CollectionUtils

java.lang.Object

net.gdface.utils.CollectionUtils

public class CollectionUtils
extends java.lang.Object

作者:

guyadong

嵌套类概要

嵌套类

限定符和类型	类和说明
static interface	CollectionUtils.DualTransformer<L,R> dual transform type between L and R CollectionUtils.DualTransformer.toRight(Object) L -> R CollectionUtils.DualTransformer.fromRight(Object) R -> L
static interface	CollectionUtils.Function<F,T>

方法概要

限定符和类型	方法和说明
static <L,R> CollectionUtils.DualTransformer<L,R>	asDualTransformer(CollectionUtils.Function<L,R> t1, CollectionUtils.Function<R,L> t2)
static <L,R> CollectionUtils.Function<R,L>	asFromRightTransformer(CollectionUtils.DualTransformer<L,R> dual)
static <L,R> CollectionUtils.Function<L,R>	asToRightTransformer(CollectionUtils.DualTransformer<L,R> dual)
static <T> T	checkNotNull(T reference) Ensures that an object reference passed as a parameter to the calling method is not null.
static <T> T	checkNotNull(T reference, java.lang.Object errorMessage) Ensures that an object reference passed as a parameter to the calling method is not null.
static <C extends java.util.Collection<?>> C	checkNotNullElement(C c) Ensures that a collection reference passed as a parameter to the calling method not exists null element if it's not null.
static <K,V> java.util.Map<K,V>	merge(java.lang.Iterable<K> keys, java.lang.Iterable<V> values) 合并两个Iterable的数据为一个Map 要求两个迭代器的元素个数必须一致 如果keys中的元素为null， 则该元素和values对应value的会自动被忽略
static <K,V> java.util.Map<K,V>	merge(java.util.Iterator<K> keys, java.util.Iterator<V> values) 合并两个迭代器的数据为一个Map 要求两个迭代器的元素个数必须一致， 如果keys中的元素为null， 则该元素和values对应value的会自动被忽略
static <K,V> java.util.Map<K,V>	merge(K[] keys, V[] values) 合并两个数组的数据为一个Map 如果keys中的元素为null， 则该元素和values对应value的会自动被忽略
static <K1,K2,V> java.util.Map<K2,V>	tranformKeys(java.util.Map<K1,V> fromMap, CollectionUtils.DualTransformer<K1,K2> transformer) Returns a view of a map where each value is transformed by a function.
static <K1,K2,V> java.util.Map<K2,V>	tranformKeys(java.util.Map<K1,V> fromMap, CollectionUtils.Function<K1,K2> transformer2, CollectionUtils.Function<K2,K1> transformer1)
static <F,T> java.util.Iterator<T>	transform(java.util.Iterator<F> fromIterator, CollectionUtils.Function<? super F,? extends T> transformer) Returns an iterator that applies function to each element of fromIterator.
static <E1,E2> java.util.Set<E2>	transform(java.util.Set<E1> fromSet, CollectionUtils.DualTransformer<E1,E2> transformer) Returns a view of a set where each key is transformed by a function.
static <E1,E2> java.util.Set<E2>	transform(java.util.Set<E1> fromSet, CollectionUtils.Function<E1,E2> transformer2, CollectionUtils.Function<E2,E1> transformer1)

从类继承的方法 java.lang.Object

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

方法详细资料

asDualTransformer

public static final <L,R> CollectionUtils.DualTransformer<L,R> asDualTransformer(CollectionUtils.Function<L,R> t1,
                                                                                 CollectionUtils.Function<R,L> t2)

asToRightTransformer

public static final <L,R> CollectionUtils.Function<L,R> asToRightTransformer(CollectionUtils.DualTransformer<L,R> dual)

asFromRightTransformer

public static final <L,R> CollectionUtils.Function<R,L> asFromRightTransformer(CollectionUtils.DualTransformer<L,R> dual)

checkNotNull

public static <T> T checkNotNull(T reference)

Ensures that an object reference passed as a parameter to the calling method is not null.

返回:

the non-null reference that was validated

checkNotNull

public static <T> T checkNotNull(T reference,
                                 java.lang.Object errorMessage)

Ensures that an object reference passed as a parameter to the calling method is not null.

返回:

the non-null reference that was validated

checkNotNullElement

public static <C extends java.util.Collection<?>> C checkNotNullElement(C c)

Ensures that a collection reference passed as a parameter to the calling method not exists null element if it's not null.

返回:

the non-null-element reference that was validated

tranformKeys

public static final <K1,K2,V> java.util.Map<K2,V> tranformKeys(java.util.Map<K1,V> fromMap,
                                                               CollectionUtils.Function<K1,K2> transformer2,
                                                               CollectionUtils.Function<K2,K1> transformer1)

另请参阅:

tranformKeys(Map, DualTransformer)

tranformKeys

public static final <K1,K2,V> java.util.Map<K2,V> tranformKeys(java.util.Map<K1,V> fromMap,
                                                               CollectionUtils.DualTransformer<K1,K2> transformer)

Returns a view of a map where each value is transformed by a function. All other properties of the map, such as iteration order, are left intact.
see also com.google.common.collect.Maps#transformEntries(Map, com.google.common.collect.Maps.EntryTransformer)

参数:

fromMap -

transformer -

返回:

Map transformed

transform

public static final <E1,E2> java.util.Set<E2> transform(java.util.Set<E1> fromSet,
                                                        CollectionUtils.Function<E1,E2> transformer2,
                                                        CollectionUtils.Function<E2,E1> transformer1)

另请参阅:

transform(Set, DualTransformer)

transform

public static final <E1,E2> java.util.Set<E2> transform(java.util.Set<E1> fromSet,
                                                        CollectionUtils.DualTransformer<E1,E2> transformer)

Returns a view of a set where each key is transformed by a function. All other properties of the map, such as iteration order, are left intact.
see also com.google.common.collect.Maps#transformEntries(Map, com.google.common.collect.Maps.EntryTransformer)

参数:

fromSet -

transformer -

返回:

Set transformed

transform

public static <F,T> java.util.Iterator<T> transform(java.util.Iterator<F> fromIterator,
                                                    CollectionUtils.Function<? super F,? extends T> transformer)

Returns an iterator that applies function to each element of fromIterator.
see also com.google.common.collect.Iterators#transform(Iterator, com.google.common.base.Function)

参数:

fromIterator -

transformer -

返回:

an iterator that applies function to each element of fromIterator

merge

public static <K,V> java.util.Map<K,V> merge(java.util.Iterator<K> keys,
                                             java.util.Iterator<V> values)

合并两个迭代器的数据为一个Map
要求两个迭代器的元素个数必须一致， 如果keys中的元素为null， 则该元素和values对应value的会自动被忽略

参数:

keys -

values -

返回:

合并后的Map

merge

public static <K,V> java.util.Map<K,V> merge(java.lang.Iterable<K> keys,
                                             java.lang.Iterable<V> values)

合并两个Iterable的数据为一个Map
要求两个迭代器的元素个数必须一致 如果keys中的元素为null， 则该元素和values对应value的会自动被忽略

参数:

keys -

values -

返回:

合并后的Map

merge

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

合并两个数组的数据为一个Map
如果keys中的元素为null， 则该元素和values对应value的会自动被忽略

参数:

keys -

values -

返回:

合并后的Map