|
Java example source code file (FilteredKeyMultimap.java)
This example Java source code file (FilteredKeyMultimap.java) is included in the alvinalexander.com
"Java Source Code
Warehouse" project. The intent of this project is to help you "Learn
Java by Example" TM.
Learn more about this Java project at its project page.
The FilteredKeyMultimap.java Java example source code
/*
* Copyright (C) 2012 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 static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkPositionIndex;
import com.google.common.annotations.GwtCompatible;
import com.google.common.base.Predicate;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.j2objc.annotations.WeakOuter;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import javax.annotation.Nullable;
/**
* Implementation of {@link Multimaps#filterKeys(Multimap, Predicate)}.
*
* @author Louis Wasserman
*/
@GwtCompatible
class FilteredKeyMultimap<K, V> extends AbstractMultimap implements FilteredMultimap {
final Multimap<K, V> unfiltered;
final Predicate<? super K> keyPredicate;
FilteredKeyMultimap(Multimap<K, V> unfiltered, Predicate keyPredicate) {
this.unfiltered = checkNotNull(unfiltered);
this.keyPredicate = checkNotNull(keyPredicate);
}
@Override
public Multimap<K, V> unfiltered() {
return unfiltered;
}
@Override
public Predicate<? super Entry entryPredicate() {
return Maps.keyPredicateOnEntries(keyPredicate);
}
@Override
public int size() {
int size = 0;
for (Collection<V> collection : asMap().values()) {
size += collection.size();
}
return size;
}
@Override
public boolean containsKey(@Nullable Object key) {
if (unfiltered.containsKey(key)) {
@SuppressWarnings("unchecked") // k is equal to a K, if not one itself
K k = (K) key;
return keyPredicate.apply(k);
}
return false;
}
@Override
public Collection<V> removeAll(Object key) {
return containsKey(key) ? unfiltered.removeAll(key) : unmodifiableEmptyCollection();
}
Collection<V> unmodifiableEmptyCollection() {
if (unfiltered instanceof SetMultimap) {
return ImmutableSet.of();
} else {
return ImmutableList.of();
}
}
@Override
public void clear() {
keySet().clear();
}
@Override
Set<K> createKeySet() {
return Sets.filter(unfiltered.keySet(), keyPredicate);
}
@Override
public Collection<V> get(K key) {
if (keyPredicate.apply(key)) {
return unfiltered.get(key);
} else if (unfiltered instanceof SetMultimap) {
return new AddRejectingSet<K, V>(key);
} else {
return new AddRejectingList<K, V>(key);
}
}
static class AddRejectingSet<K, V> extends ForwardingSet {
final K key;
AddRejectingSet(K key) {
this.key = key;
}
@Override
public boolean add(V element) {
throw new IllegalArgumentException("Key does not satisfy predicate: " + key);
}
@Override
public boolean addAll(Collection<? extends V> collection) {
checkNotNull(collection);
throw new IllegalArgumentException("Key does not satisfy predicate: " + key);
}
@Override
protected Set<V> delegate() {
return Collections.emptySet();
}
}
static class AddRejectingList<K, V> extends ForwardingList {
final K key;
AddRejectingList(K key) {
this.key = key;
}
@Override
public boolean add(V v) {
add(0, v);
return true;
}
@Override
public boolean addAll(Collection<? extends V> collection) {
addAll(0, collection);
return true;
}
@Override
public void add(int index, V element) {
checkPositionIndex(index, 0);
throw new IllegalArgumentException("Key does not satisfy predicate: " + key);
}
@CanIgnoreReturnValue
@Override
public boolean addAll(int index, Collection<? extends V> elements) {
checkNotNull(elements);
checkPositionIndex(index, 0);
throw new IllegalArgumentException("Key does not satisfy predicate: " + key);
}
@Override
protected List<V> delegate() {
return Collections.emptyList();
}
}
@Override
Iterator<Entry entryIterator() {
throw new AssertionError("should never be called");
}
@Override
Collection<Entry createEntries() {
return new Entries();
}
@WeakOuter
class Entries extends ForwardingCollection<Entry {
@Override
protected Collection<Entry delegate() {
return Collections2.filter(unfiltered.entries(), entryPredicate());
}
@Override
@SuppressWarnings("unchecked")
public boolean remove(@Nullable Object o) {
if (o instanceof Entry) {
Entry<?, ?> entry = (Entry) o;
if (unfiltered.containsKey(entry.getKey())
// if this holds, then we know entry.getKey() is a K
&& keyPredicate.apply((K) entry.getKey())) {
return unfiltered.remove(entry.getKey(), entry.getValue());
}
}
return false;
}
}
@Override
Collection<V> createValues() {
return new FilteredMultimapValues<K, V>(this);
}
@Override
Map<K, Collection createAsMap() {
return Maps.filterKeys(unfiltered.asMap(), keyPredicate);
}
@Override
Multiset<K> createKeys() {
return Multisets.filter(unfiltered.keys(), keyPredicate);
}
}
Other Java examples (source code examples)
Here is a short list of links related to this Java FilteredKeyMultimap.java source code file:
|