/**
    * Copyright 2010-2013 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<String> 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 <code>properties</code> is already immutable, no new object is created, the
  	 * <code>properties</code> 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 <code>properties</code> is already immutable, no new object is created, the
  	 * <code>properties</code> 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<String, String> 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<? extends Object, ? extends Object> t) {
 		throw new UnsupportedOperationException(UOE_MSG);
 	}
 
 	@Override
 	public void clear() {
 		throw new UnsupportedOperationException(UOE_MSG);
 	}
 
 	@Override
 	public Set<Object> keySet() {
 		return ImmutableSet.copyOf(super.keySet());
 	}
 
 	@Override
 	public Set<java.util.Map.Entry<Object, Object>> entrySet() {
 		return ImmutableSet.copyOf(super.entrySet());
 	}
 
 	@Override
 	public Collection<Object> values() {
 		return ImmutableList.copyOf(super.values());
 	}
 
 }