org.apache.commons.collections4.SplitMapUtils Maven / Gradle / Ivy
/*
* 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;
import java.util.Collection;
import java.util.Map;
import java.util.Set;
import org.apache.commons.collections4.collection.UnmodifiableCollection;
import org.apache.commons.collections4.iterators.UnmodifiableMapIterator;
import org.apache.commons.collections4.map.EntrySetToMapIteratorAdapter;
import org.apache.commons.collections4.map.UnmodifiableEntrySet;
import org.apache.commons.collections4.set.UnmodifiableSet;
/**
* Utilities for working with "split maps:" objects that implement {@link Put}
* and/or {@link Get} but not {@link Map}.
*
* @since 4.0
*
* @see Get
* @see Put
*/
public class SplitMapUtils {
/**
* SplitMapUtils should not normally be instantiated.
*/
private SplitMapUtils() {}
//-----------------------------------------------------------------------
private static class WrappedGet implements IterableMap, Unmodifiable {
private final Get get;
private WrappedGet(final Get get) {
this.get = get;
}
@Override
public void clear() {
throw new UnsupportedOperationException();
}
@Override
public boolean containsKey(final Object key) {
return get.containsKey(key);
}
@Override
public boolean containsValue(final Object value) {
return get.containsValue(value);
}
@Override
public Set> entrySet() {
return UnmodifiableEntrySet.unmodifiableEntrySet(get.entrySet());
}
@Override
public boolean equals(final Object arg0) {
if (arg0 == this) {
return true;
}
return arg0 instanceof WrappedGet && ((WrappedGet) arg0).get.equals(this.get);
}
@Override
public V get(final Object key) {
return get.get(key);
}
@Override
public int hashCode() {
return ("WrappedGet".hashCode() << 4) | get.hashCode();
}
@Override
public boolean isEmpty() {
return get.isEmpty();
}
@Override
public Set keySet() {
return UnmodifiableSet.unmodifiableSet(get.keySet());
}
@Override
public V put(final K key, final V value) {
throw new UnsupportedOperationException();
}
@Override
public void putAll(final Map t) {
throw new UnsupportedOperationException();
}
@Override
public V remove(final Object key) {
return get.remove(key);
}
@Override
public int size() {
return get.size();
}
@Override
public Collection values() {
return UnmodifiableCollection.unmodifiableCollection(get.values());
}
@Override
public MapIterator mapIterator() {
MapIterator it;
if (get instanceof IterableGet) {
it = ((IterableGet) get).mapIterator();
} else {
it = new EntrySetToMapIteratorAdapter<>(get.entrySet());
}
return UnmodifiableMapIterator.unmodifiableMapIterator(it);
}
}
private static class WrappedPut implements Map, Put {
private final Put put;
private WrappedPut(final Put put) {
this.put = put;
}
@Override
public void clear() {
put.clear();
}
@Override
public boolean containsKey(final Object key) {
throw new UnsupportedOperationException();
}
@Override
public boolean containsValue(final Object value) {
throw new UnsupportedOperationException();
}
@Override
public Set> entrySet() {
throw new UnsupportedOperationException();
}
@Override
public boolean equals(final Object obj) {
if (obj == this) {
return true;
}
return obj instanceof WrappedPut && ((WrappedPut) obj).put.equals(this.put);
}
@Override
public V get(final Object key) {
throw new UnsupportedOperationException();
}
@Override
public int hashCode() {
return ("WrappedPut".hashCode() << 4) | put.hashCode();
}
@Override
public boolean isEmpty() {
throw new UnsupportedOperationException();
}
@Override
public Set keySet() {
throw new UnsupportedOperationException();
}
@Override
@SuppressWarnings("unchecked")
public V put(final K key, final V value) {
return (V) put.put(key, value);
}
@Override
public void putAll(final Map t) {
put.putAll(t);
}
@Override
public V remove(final Object key) {
throw new UnsupportedOperationException();
}
@Override
public int size() {
throw new UnsupportedOperationException();
}
@Override
public Collection values() {
throw new UnsupportedOperationException();
}
}
//-----------------------------------------------------------------------
/**
* Get the specified {@link Get} as an instance of {@link IterableMap}.
* If get implements {@link IterableMap} directly, no conversion will take place.
* If get implements {@link Map} but not {@link IterableMap} it will be decorated.
* Otherwise an {@link Unmodifiable} {@link IterableMap} will be returned.
* @param the key type
* @param the value type
* @param get to wrap, must not be null
* @return {@link IterableMap}
* @throws NullPointerException if the argument is null
*/
@SuppressWarnings("unchecked")
public static IterableMap readableMap(final Get get) {
if (get == null) {
throw new NullPointerException("Get must not be null");
}
if (get instanceof Map) {
return get instanceof IterableMap ?
((IterableMap) get) :
MapUtils.iterableMap((Map) get);
}
return new WrappedGet<>(get);
}
/**
* Get the specified {@link Put} as an instanceof {@link Map}.
* If put implements {@link Map} directly, no conversion will take place.
* Otherwise a write-only {@link Map} will be returned. On such a {@link Map}
* it is recommended that the result of #put(K, V) be discarded as it likely will not
* match V at runtime.
*
* @param the key type
* @param the element type
* @param put to wrap, must not be null
* @return {@link Map}
* @throws NullPointerException if the argument is null
*/
@SuppressWarnings("unchecked")
public static Map writableMap(final Put put) {
if (put == null) {
throw new NullPointerException("Put must not be null");
}
if (put instanceof Map) {
return (Map) put;
}
return new WrappedPut<>(put);
}
}