src/main/java/org/apache/sling/feature/MapWithMetadata.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.sling.feature;

import java.util.Collection;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;

/**
 * Helper class to maintain metadata for a map
 * @since 1.7.0
 */
class MapWithMetadata implements Map<String, String> {

    private final Map<String, String> values = new LinkedHashMap<>();

    private final Map<String, Map<String, Object>> metadata = new HashMap<>();

    public Map<String, Object> getMetadata(final String key) {
        if (values.containsKey(key) ) {
            return metadata.computeIfAbsent(key, id -> new LinkedHashMap<>());
        }
        metadata.remove(key);
        return null;
    }

	@Override
	public void clear() {
        this.values.clear();
        this.metadata.clear();
	}

	@Override
	public boolean containsKey(final Object key) {
		return this.values.containsKey(key);
	}

	@Override
	public boolean containsValue(final Object value) {
		return this.values.containsValue(value);
	}

	@Override
	public Set<Entry<String, String>> entrySet() {
		return this.values.entrySet();
	}

	@Override
	public String get(final Object key) {
		return this.values.get(key);
	}

	@Override
	public boolean isEmpty() {
		return this.values.isEmpty();
	}

	@Override
	public Set<String> keySet() {
		return this.values.keySet();
	}

	@Override
	public String put(final String key, final String value) {
		return this.values.put(key, value);
	}

	@Override
	public void putAll(final Map<? extends String, ? extends String> m) {
        this.values.putAll(m);
	}

	@Override
	public String remove(final Object key) {
        this.metadata.remove(key);
        return this.values.remove(key);
	}

	@Override
	public int size() {
		return this.values.size();
	}

	@Override
	public Collection<String> values() {
		return this.values.values();
    }

	/* (non-Javadoc)
	 * @see java.lang.Object#hashCode()
	 */
	@Override
	public int hashCode() {
		return values.hashCode();
	}

	/* (non-Javadoc)
	 * @see java.lang.Object#equals(java.lang.Object)
	 */
	@Override
	public boolean equals(final Object obj) {
		if (this == obj) {
            return true;
        }
        if ( obj instanceof MapWithMetadata ) {
            return this.values.equals((MapWithMetadata)obj);
        }
        if ( !(obj instanceof Map)) {
            return false;
        }
        return this.values.equals(obj);
	}

	/* (non-Javadoc)
	 * @see java.lang.Object#toString()
	 */
	@Override
	public String toString() {
		return values.toString();
	}    
}