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Kuali Utilities
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/**
 * Copyright 2010-2014 The Kuali Foundation
 *
 * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
 *
 * 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.kuali.common.util.property;

import static com.google.common.base.Preconditions.checkArgument;
import static org.kuali.common.util.base.Precondition.checkNotNull;

import java.io.InputStream;
import java.io.Reader;
import java.util.Collection;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;

public final class ImmutableProperties extends Properties {

	private static final long serialVersionUID = -3964884087103719367L;
	private static final String UOE_MSG = "Immutable properties cannot be changed";
	private static final Properties EMPTY = copyOf(new Properties());

	public ImmutableProperties(Properties original) {
		checkNotNull(original, "original");

		// Prevent anything from changing original until we are done
		synchronized (original) {

			// Extract only those keys where both the key and its corresponding value are strings
			Set keys = original.stringPropertyNames();

			// If the sizes are different, original contains at least one key or value that is not a string
			checkArgument(keys.size() == original.size(), "Immutable properties only support strings");

			// Copy every key/value pair from original - can't use putAll() since it calls put() which is now disabled
			for (String key : keys) {
				super.put(key, original.getProperty(key));
			}
		}
	}

	public static Properties of() {
		return EMPTY;
	}

	/**
	 * Create and return a new immutable properties object identical to the one passed in. If properties is already immutable, no new object is created, the
	 * properties object passed in as a method argument is what is returned.
	 * 
	 * @throws NullPointerException
	 *             if {@code properties} is null
	 * 
	 * @deprecated use copyOf(Properties) instead
	 */
	@Deprecated
	public static Properties of(Properties properties) {
		return copyOf(properties);
	}

	/**
	 * Create and return a new immutable properties object identical to the one passed in. If properties is already immutable, no new object is created, the
	 * properties object passed in as a method argument is what is returned.
	 * 
	 * @throws NullPointerException
	 *             if {@code properties} is null
	 */
	public static ImmutableProperties copyOf(Properties properties) {
		if (properties instanceof ImmutableProperties) {
			return (ImmutableProperties) properties;
		} else {
			return new ImmutableProperties(properties);
		}
	}

	public static ImmutableProperties copyOf(Map map) {
		Properties properties = new Properties();
		for (String key : map.keySet()) {
			properties.setProperty(key, map.get(key));
		}
		return copyOf(properties);
	}

	@Override
	public Object setProperty(String key, String value) {
		throw new UnsupportedOperationException(UOE_MSG);
	}

	@Override
	public void load(Reader reader) {
		throw new UnsupportedOperationException(UOE_MSG);
	}

	@Override
	public void load(InputStream inStream) {
		throw new UnsupportedOperationException(UOE_MSG);
	}

	@Override
	public void loadFromXML(InputStream in) {
		throw new UnsupportedOperationException(UOE_MSG);
	}

	@Override
	public Object put(Object key, Object value) {
		throw new UnsupportedOperationException(UOE_MSG);
	}

	@Override
	public Object remove(Object key) {
		throw new UnsupportedOperationException(UOE_MSG);
	}

	@Override
	public void putAll(Map t) {
		throw new UnsupportedOperationException(UOE_MSG);
	}

	@Override
	public void clear() {
		throw new UnsupportedOperationException(UOE_MSG);
	}

	@Override
	public Set