com.google.common.collect.Platform Maven / Gradle / Ivy
/*
* Copyright (C) 2008 The Guava Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.common.collect;
import com.google.common.annotations.GwtCompatible;
import com.google.common.base.Function;
import com.google.common.base.Predicate;
import com.google.common.collect.Maps.EntryTransformer;
import java.lang.reflect.Array;
import java.util.Collections;
import java.util.Map;
import java.util.NavigableMap;
import java.util.NavigableSet;
import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;
/**
* Methods factored out so that they can be emulated differently in GWT.
*
* @author Hayward Chan
*/
@GwtCompatible(emulated = true)
final class Platform {
/**
* Returns a new array of the given length with the same type as a reference
* array.
*
* @param reference any array of the desired type
* @param length the length of the new array
*/
static T[] newArray(T[] reference, int length) {
Class> type = reference.getClass().getComponentType();
// the cast is safe because
// result.getClass() == reference.getClass().getComponentType()
@SuppressWarnings("unchecked")
T[] result = (T[]) Array.newInstance(type, length);
return result;
}
static Set newSetFromMap(Map map) {
return Collections.newSetFromMap(map);
}
/**
* Configures the given map maker to use weak keys, if possible; does nothing
* otherwise (i.e., in GWT). This is sometimes acceptable, when only
* server-side code could generate enough volume that reclamation becomes
* important.
*/
static MapMaker tryWeakKeys(MapMaker mapMaker) {
return mapMaker.weakKeys();
}
static SortedMap mapsTransformEntriesSortedMap(
SortedMap fromMap,
EntryTransformer super K, ? super V1, V2> transformer) {
return (fromMap instanceof NavigableMap)
? Maps.transformEntries((NavigableMap) fromMap, transformer)
: Maps.transformEntriesIgnoreNavigable(fromMap, transformer);
}
static SortedMap mapsAsMapSortedSet(SortedSet set,
Function super K, V> function) {
return (set instanceof NavigableSet)
? Maps.asMap((NavigableSet) set, function)
: Maps.asMapSortedIgnoreNavigable(set, function);
}
static SortedSet setsFilterSortedSet(SortedSet set,
Predicate super E> predicate) {
return (set instanceof NavigableSet)
? Sets.filter((NavigableSet) set, predicate)
: Sets.filterSortedIgnoreNavigable(set, predicate);
}
static SortedMap mapsFilterSortedMap(SortedMap map,
Predicate super Map.Entry> predicate) {
return (map instanceof NavigableMap)
? Maps.filterEntries((NavigableMap) map, predicate)
: Maps.filterSortedIgnoreNavigable(map, predicate);
}
private Platform() {}
}