org.conqat.lib.commons.collections.CaseInsensitiveMap Maven / Gradle / Ivy

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Provides common utility functions
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/*
 * Copyright (c) CQSE GmbH
 *
 * 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.conqat.lib.commons.collections;

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

/**
 * Map implementation that supports case-insensitive String keys. Note that while the method
 * signatures of the {@link Map} interface allows arbitrary Objects as keys, this class will throw
 * {@link IllegalArgumentException}s when using non String keys (null keys are supported). Also note
 * that {link {@link #keySet()}} will return lower cased keys.
 */
public class CaseInsensitiveMap implements Map {

	/** The delegate map */
	private final Map delegateMap = new HashMap<>();

	/** {@inheritDoc} */
	@Override
	public int size() {
		return delegateMap.size();
	}

	/** {@inheritDoc} */
	@Override
	public boolean isEmpty() {
		return delegateMap.isEmpty();
	}

	/** {@inheritDoc} */
	@Override
	public boolean containsKey(Object key) {
		return delegateMap.containsKey(preprocessKey(key));
	}

	/** {@inheritDoc} */
	@Override
	public boolean containsValue(Object value) {
		return delegateMap.containsValue(value);
	}

	/** {@inheritDoc} */
	@Override
	public T get(Object key) {
		return delegateMap.get(preprocessKey(key));
	}

	/** {@inheritDoc} */
	@Override
	public T put(String key, T value) {
		return delegateMap.put(preprocessKey(key), value);
	}

	/** {@inheritDoc} */
	@Override
	public T remove(Object key) {
		return delegateMap.remove(preprocessKey(key));
	}

	/** {@inheritDoc} */
	@Override
	public void putAll(Map m) {
		for (java.util.Map.Entry entry : m.entrySet()) {
			delegateMap.put(preprocessKey(entry.getKey()), entry.getValue());
		}
	}

	/** {@inheritDoc} */
	@Override
	public void clear() {
		delegateMap.clear();
	}

	/**
	 * Returns the keys of this map in lower case. Note that this (mutable) set does no longer
	 * possess the case-insensitivity feature.
	 */
	@Override
	public Set keySet() {
		return delegateMap.keySet();
	}

	/** {@inheritDoc} */
	@Override
	public Collection values() {
		return delegateMap.values();
	}

	/**
	 * Returns the entries of this map. The keys of the entries will we in lower case.
	 */
	/** {@inheritDoc} */
	@Override
	public Set> entrySet() {
		return delegateMap.entrySet();
	}

	/**
	 * Preprocesses a key by converting it to lower case. This can handle null keys.
	 */
	private static String preprocessKey(Object key) {
		if (key == null) {
			return null;
		}
		if (key instanceof String) {
			return ((String) key).toLowerCase();
		}
		throw new IllegalArgumentException("Only keys of type String allowed");
	}

	/** {@inheritDoc} */
	@Override
	public String toString() {
		return delegateMap.toString();
	}
}