/*
* 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> 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 <E>
Set<E>
newSetFromMap(
Map<E,
Boolean>
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 <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);
}
static <K, V>
SortedMap<K, V>
mapsAsMapSortedSet(
SortedSet<K>
set,
Function<? super K, V>
function) {
return (
set instanceof
NavigableSet)
?
Maps.
asMap((
NavigableSet<K>)
set,
function)
:
Maps.
asMapSortedIgnoreNavigable(
set,
function);
}
static <E>
SortedSet<E>
setsFilterSortedSet(
SortedSet<E>
set,
Predicate<? super E>
predicate) {
return (
set instanceof
NavigableSet)
?
Sets.
filter((
NavigableSet<E>)
set,
predicate)
:
Sets.
filterSortedIgnoreNavigable(
set,
predicate);
}
static <K, V>
SortedMap<K, V>
mapsFilterSortedMap(
SortedMap<K, V>
map,
Predicate<? super
Map.
Entry<K, V>>
predicate) {
return (
map instanceof
NavigableMap)
?
Maps.
filterEntries((
NavigableMap<K, V>)
map,
predicate)
:
Maps.
filterSortedIgnoreNavigable(
map,
predicate);
}
private
Platform() {}
}