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/*
* 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.collect.Maps.EntryTransformer;
import java.lang.reflect.Array;
import java.util.NavigableMap;
import java.util.SortedMap;
/**
* Methods factored out so that they can be emulated differently in GWT.
*
* @author Hayward Chan
*/
@GwtCompatible(emulated = true)
class Platform {
/**
* Clone the given array using {@link Object#clone()}. It is factored out so
* that it can be emulated in GWT.
*/
static <T> T[] clone(T[] array) {
return array.clone();
}
/**
* 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> 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;
}
/**
* 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 <K, V1, V2> SortedMap<K, V2> mapsTransformEntriesSortedMap(
SortedMap<K, V1> fromMap,
EntryTransformer<? super K, ? super V1, V2> transformer) {
return (fromMap instanceof NavigableMap)
? Maps.transformEntries((NavigableMap<K, V1>) fromMap, transformer)
: Maps.transformEntriesIgnoreNavigable(fromMap, transformer);
}
private Platform() {}
}
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