HashMultiSet.java
- /*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You 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.apache.commons.collections4.multiset;
- import java.io.IOException;
- import java.io.ObjectInputStream;
- import java.io.ObjectOutputStream;
- import java.io.Serializable;
- import java.util.Collection;
- import java.util.HashMap;
- /**
- * Implements {@code MultiSet}, using a {@link HashMap} to provide the
- * data storage. This is the standard implementation of a multiset.
- * <p>
- * A {@code MultiSet} stores each object in the collection together with a
- * count of occurrences. Extra methods on the interface allow multiple copies
- * of an object to be added or removed at once.
- * </p>
- *
- * @param <E> the type held in the multiset
- * @since 4.1
- */
- public class HashMultiSet<E> extends AbstractMapMultiSet<E> implements Serializable {
- /** Serial version lock */
- private static final long serialVersionUID = 20150610L;
- /**
- * Constructs an empty {@link HashMultiSet}.
- */
- public HashMultiSet() {
- super(new HashMap<>());
- }
- /**
- * Constructs a multiset containing all the members of the given collection.
- *
- * @param coll a collection to copy into this multiset
- */
- public HashMultiSet(final Collection<? extends E> coll) {
- this();
- addAll(coll);
- }
- /**
- * Deserializes the multiset in using a custom routine.
- *
- * @param in the input stream
- * @throws IOException if an error occurs while reading from the stream
- * @throws ClassNotFoundException if an object read from the stream cannot be loaded
- */
- private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
- in.defaultReadObject();
- setMap(new HashMap<>());
- super.doReadObject(in);
- }
- /**
- * Serializes this object to an ObjectOutputStream.
- *
- * @param out the target ObjectOutputStream.
- * @throws IOException thrown when an I/O errors occur writing to the target stream.
- */
- private void writeObject(final ObjectOutputStream out) throws IOException {
- out.defaultWriteObject();
- super.doWriteObject(out);
- }
- }