org.testifyproject.guava.common.collect.AbstractMultiset Maven / Gradle / Ivy
/*
* Copyright (C) 2007 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 org.testifyproject.guava.common.collect;
import static org.testifyproject.guava.common.collect.Multisets.setCountImpl;
import org.testifyproject.guava.common.annotations.GwtCompatible;
import org.testifyproject.guava.common.base.Objects;
import org.testifyproject.guava.errorprone.annotations.CanIgnoreReturnValue;
import org.testifyproject.guava.j2objc.annotations.WeakOuter;
import java.util.AbstractCollection;
import java.util.Collection;
import java.util.Iterator;
import java.util.Set;
import javax.annotation.Nullable;
/**
* This class provides a skeletal implementation of the {@link Multiset}
* interface. A new multiset implementation can be created easily by extending
* this class and implementing the {@link Multiset#entrySet()} method, plus
* optionally overriding {@link #add(Object, int)} and
* {@link #remove(Object, int)} to enable modifications to the multiset.
*
* The {@link #count} and {@link #size} implementations all iterate across
* the set returned by {@link Multiset#entrySet()}, as do many methods acting on
* the set returned by {@link #elementSet()}. Override those methods for better
* performance.
*
* @author Kevin Bourrillion
* @author Louis Wasserman
*/
@GwtCompatible
abstract class AbstractMultiset extends AbstractCollection implements Multiset {
// Query Operations
@Override
public int size() {
return Multisets.sizeImpl(this);
}
@Override
public boolean isEmpty() {
return entrySet().isEmpty();
}
@Override
public boolean contains(@Nullable Object element) {
return count(element) > 0;
}
@Override
public Iterator iterator() {
return Multisets.iteratorImpl(this);
}
@Override
public int count(@Nullable Object element) {
for (Entry entry : entrySet()) {
if (Objects.equal(entry.getElement(), element)) {
return entry.getCount();
}
}
return 0;
}
// Modification Operations
@CanIgnoreReturnValue
@Override
public boolean add(@Nullable E element) {
add(element, 1);
return true;
}
@CanIgnoreReturnValue
@Override
public int add(@Nullable E element, int occurrences) {
throw new UnsupportedOperationException();
}
@CanIgnoreReturnValue
@Override
public boolean remove(@Nullable Object element) {
return remove(element, 1) > 0;
}
@CanIgnoreReturnValue
@Override
public int remove(@Nullable Object element, int occurrences) {
throw new UnsupportedOperationException();
}
@CanIgnoreReturnValue
@Override
public int setCount(@Nullable E element, int count) {
return setCountImpl(this, element, count);
}
@CanIgnoreReturnValue
@Override
public boolean setCount(@Nullable E element, int oldCount, int newCount) {
return setCountImpl(this, element, oldCount, newCount);
}
// Bulk Operations
/**
* {@inheritDoc}
*
* This implementation is highly efficient when {@code elementsToAdd}
* is itself a {@link Multiset}.
*/
@CanIgnoreReturnValue
@Override
public boolean addAll(Collection elementsToAdd) {
return Multisets.addAllImpl(this, elementsToAdd);
}
@CanIgnoreReturnValue
@Override
public boolean removeAll(Collection elementsToRemove) {
return Multisets.removeAllImpl(this, elementsToRemove);
}
@CanIgnoreReturnValue
@Override
public boolean retainAll(Collection elementsToRetain) {
return Multisets.retainAllImpl(this, elementsToRetain);
}
@Override
public void clear() {
Iterators.clear(entryIterator());
}
// Views
private transient Set elementSet;
@Override
public Set elementSet() {
Set result = elementSet;
if (result == null) {
elementSet = result = createElementSet();
}
return result;
}
/**
* Creates a new instance of this multiset's element set, which will be
* returned by {@link #elementSet()}.
*/
Set createElementSet() {
return new ElementSet();
}
@WeakOuter
class ElementSet extends Multisets.ElementSet {
@Override
Multiset multiset() {
return AbstractMultiset.this;
}
}
abstract Iterator> entryIterator();
abstract int distinctElements();
private transient Set> entrySet;
@Override
public Set> entrySet() {
Set> result = entrySet;
if (result == null) {
entrySet = result = createEntrySet();
}
return result;
}
@WeakOuter
class EntrySet extends Multisets.EntrySet {
@Override
Multiset multiset() {
return AbstractMultiset.this;
}
@Override
public Iterator> iterator() {
return entryIterator();
}
@Override
public int size() {
return distinctElements();
}
}
Set> createEntrySet() {
return new EntrySet();
}
// Object methods
/**
* {@inheritDoc}
*
* This implementation returns {@code true} if {@code object} is a multiset
* of the same size and if, for each element, the two multisets have the same
* count.
*/
@Override
public boolean equals(@Nullable Object object) {
return Multisets.equalsImpl(this, object);
}
/**
* {@inheritDoc}
*
*
This implementation returns the hash code of {@link
* Multiset#entrySet()}.
*/
@Override
public int hashCode() {
return entrySet().hashCode();
}
/**
* {@inheritDoc}
*
*
This implementation returns the result of invoking {@code toString} on
* {@link Multiset#entrySet()}.
*/
@Override
public String toString() {
return entrySet().toString();
}
}