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 * 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.
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package org.apache.commons.collections4.map;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.Iterator;
import java.util.Map;

import org.apache.commons.collections4.Predicate;

Decorates another Map to validate that additions
match a specified predicate.

This map exists to provide validation for the decorated map.
It is normally created to decorate an empty map.
If an object cannot be added to the map, an IllegalArgumentException is thrown.


One usage would be to ensure that no null keys are added to the map.

Map map = PredicatedSet.decorate(new HashMap(), NotNullPredicate.INSTANCE, null);

Note that PredicatedMap is not synchronized and is not thread-safe. If you wish to use this map from multiple threads concurrently, you must use appropriate synchronization. The simplest approach is to wrap this map using Collections.synchronizedMap(Map<Object,Object>). This class may throw exceptions when accessed by concurrent threads without synchronization. 

This class is Serializable from Commons Collections 3.1.

Type parameters:
<K> – the type of the keys in this map
<V> – the type of the values in this map
Since:
3.0/**
 * Decorates another <code>Map</code> to validate that additions
 * match a specified predicate.
 * <p>
 * This map exists to provide validation for the decorated map.
 * It is normally created to decorate an empty map.
 * If an object cannot be added to the map, an IllegalArgumentException is thrown.
 * </p>
 * <p>
 * One usage would be to ensure that no null keys are added to the map.
 * </p>
 * <pre>Map map = PredicatedSet.decorate(new HashMap(), NotNullPredicate.INSTANCE, null);</pre>
 * <p>
 * <strong>Note that PredicatedMap is not synchronized and is not thread-safe.</strong>
 * If you wish to use this map from multiple threads concurrently, you must use
 * appropriate synchronization. The simplest approach is to wrap this map
 * using {@link java.util.Collections#synchronizedMap(Map)}. This class may throw
 * exceptions when accessed by concurrent threads without synchronization.
 * </p>
 * <p>
 * This class is Serializable from Commons Collections 3.1.
 * </p>
 *
 * @param <K> the type of the keys in this map
 * @param <V> the type of the values in this map
 * @since 3.0
 */
public class PredicatedMap<K, V>
        extends AbstractInputCheckedMapDecorator<K, V>
        implements Serializable {

    
Serialization version /** Serialization version */
    private static final long serialVersionUID = 7412622456128415156L;

    
The key predicate to use /** The key predicate to use */
    protected final Predicate<? super K> keyPredicate;

    
The value predicate to use /** The value predicate to use */
    protected final Predicate<? super V> valuePredicate;

    
Factory method to create a predicated (validating) map.

If there are any elements already in the list being decorated, they
are validated.
Params:
map –  the map to decorate, must not be null
keyPredicate –  the predicate to validate the keys, null means no check
valuePredicate –  the predicate to validate to values, null means no check
Type parameters:
<K> –  the key type
<V> –  the value type
Throws:
NullPointerException – if the map is null
Returns:
a new predicated map
Since:
4.0/**
     * Factory method to create a predicated (validating) map.
     * <p>
     * If there are any elements already in the list being decorated, they
     * are validated.
     *
     * @param <K>  the key type
     * @param <V>  the value type
     * @param map  the map to decorate, must not be null
     * @param keyPredicate  the predicate to validate the keys, null means no check
     * @param valuePredicate  the predicate to validate to values, null means no check
     * @return a new predicated map
     * @throws NullPointerException if the map is null
     * @since 4.0
     */
    public static <K, V> PredicatedMap<K, V> predicatedMap(final Map<K, V> map,
                                                           final Predicate<? super K> keyPredicate,
                                                           final Predicate<? super V> valuePredicate) {
        return new PredicatedMap<>(map, keyPredicate, valuePredicate);
    }

    //-----------------------------------------------------------------------
    
Constructor that wraps (not copies).
Params:
map –  the map to decorate, must not be null
keyPredicate –  the predicate to validate the keys, null means no check
valuePredicate –  the predicate to validate to values, null means no check
Throws:
NullPointerException – if the map is null/**
     * Constructor that wraps (not copies).
     *
     * @param map  the map to decorate, must not be null
     * @param keyPredicate  the predicate to validate the keys, null means no check
     * @param valuePredicate  the predicate to validate to values, null means no check
     * @throws NullPointerException if the map is null
     */
    protected PredicatedMap(final Map<K, V> map, final Predicate<? super K> keyPredicate,
                            final Predicate<? super V> valuePredicate) {
        super(map);
        this.keyPredicate = keyPredicate;
        this.valuePredicate = valuePredicate;

        final Iterator<Map.Entry<K, V>> it = map.entrySet().iterator();
        while (it.hasNext()) {
            final Map.Entry<K, V> entry = it.next();
            validate(entry.getKey(), entry.getValue());
        }
    }

    //-----------------------------------------------------------------------
    
Write the map out using a custom routine.
Params:
out –  the output stream
Throws:
IOException – if an error occurs while writing to the stream
Since:
3.1/**
     * Write the map out using a custom routine.
     *
     * @param out  the output stream
     * @throws IOException if an error occurs while writing to the stream
     * @since 3.1
     */
    private void writeObject(final ObjectOutputStream out) throws IOException {
        out.defaultWriteObject();
        out.writeObject(map);
    }

    
Read the map in using a custom routine.
Params:
in –  the input stream
Throws:
IOException – if an error occurs while reading from the stream
ClassNotFoundException – if an object read from the stream can not be loaded
Since:
3.1/**
     * Read the map 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 can not be loaded
     * @since 3.1
     */
    @SuppressWarnings("unchecked") // (1) should only fail if input stream is incorrect
    private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
        in.defaultReadObject();
        map = (Map<K, V>) in.readObject(); // (1)
    }

    //-----------------------------------------------------------------------
    
Validates a key value pair.
Params:
key –  the key to validate
value –  the value to validate
Throws:
IllegalArgumentException – if invalid/**
     * Validates a key value pair.
     *
     * @param key  the key to validate
     * @param value  the value to validate
     * @throws IllegalArgumentException if invalid
     */
    protected void validate(final K key, final V value) {
        if (keyPredicate != null && keyPredicate.evaluate(key) == false) {
            throw new IllegalArgumentException("Cannot add key - Predicate rejected it");
        }
        if (valuePredicate != null && valuePredicate.evaluate(value) == false) {
            throw new IllegalArgumentException("Cannot add value - Predicate rejected it");
        }
    }

    
Override to validate an object set into the map via setValue.
Params:
value –  the value to validate
Throws:
IllegalArgumentException – if invalid
Returns:
the value itself
Since:
3.1/**
     * Override to validate an object set into the map via <code>setValue</code>.
     *
     * @param value  the value to validate
     * @return the value itself
     * @throws IllegalArgumentException if invalid
     * @since 3.1
     */
    @Override
    protected V checkSetValue(final V value) {
        if (valuePredicate.evaluate(value) == false) {
            throw new IllegalArgumentException("Cannot set value - Predicate rejected it");
        }
        return value;
    }

    
Override to only return true when there is a value transformer.
Returns:
true if a value predicate is in use
Since:
3.1/**
     * Override to only return true when there is a value transformer.
     *
     * @return true if a value predicate is in use
     * @since 3.1
     */
    @Override
    protected boolean isSetValueChecking() {
        return valuePredicate != null;
    }

    //-----------------------------------------------------------------------
    @Override
    public V put(final K key, final V value) {
        validate(key, value);
        return map.put(key, value);
    }

    @Override
    public void putAll(final Map<? extends K, ? extends V> mapToCopy) {
        for (final Map.Entry<? extends K, ? extends V> entry : mapToCopy.entrySet()) {
            validate(entry.getKey(), entry.getValue());
        }
        super.putAll(mapToCopy);
    }

}