/*
 *
 * Derby - Class org.apache.derbyTesting.functionTests.util.SystemPropertyTestSetup
 *
 * 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.derbyTesting.junit;

import java.security.PrivilegedActionException;
import java.util.Enumeration;
import java.util.Properties;


import junit.extensions.TestSetup;
import junit.framework.Test;

/**
 * Test decorator to set a set of system properties on setUp
 * and restore them to the previous values on tearDown.
 *
 */
public class SystemPropertyTestSetup extends TestSetup {
	
	protected Properties newValues;
	private Properties oldValues;
	private boolean staticProperties;
	
	/**
	 * Create a test decorator that sets and restores the passed
	 * in properties. Assumption is that the contents of
	 * properties and values will not change during execution.
	 * @param test test to be decorated
	 * @param newValues properties to be set
	 */
	public SystemPropertyTestSetup(Test test,
			Properties newValues,
			boolean staticProperties)
	{
		super(test);
		this.newValues = newValues;
		this.oldValues = new Properties();
		this.staticProperties = staticProperties;
	}

	/**
	 * Create a test decorator that sets and restores 
	 * System properties.  Do not shutdown engine after
	 * setting properties
	 * @param test
	 * @param newValues
	 */
	public SystemPropertyTestSetup(Test test,
			Properties newValues)
	{
		super(test);
		this.newValues = newValues;
		this.oldValues = new Properties();
		this.staticProperties = false;
	}
	/**
	 * For each property store the current value and
	 * replace it with the new value, unless there is no change.
	 */
    protected void setUp()
    throws java.lang.Exception
    {
    	setProperties(newValues);
    	// shutdown engine so static properties take effect
    	if (staticProperties)
    		TestConfiguration.getCurrent().shutdownEngine();
    }

    /**
     * Revert the properties to their values prior to the setUp call.
     */
    protected void tearDown()
    throws java.lang.Exception
    {
    	// Clear all the system properties set by the new set
    	// that will not be reset by the old set.
       	for (Enumeration e = newValues.propertyNames(); e.hasMoreElements();)
       	{
       		String key = (String) e.nextElement();
       		if (oldValues.getProperty(key) == null)
       		    BaseTestCase.removeSystemProperty(key);
       	}
    	// and then reset nay old values
    	setProperties(oldValues);
    	// shutdown engine to restore any static properties
    	if (staticProperties)
    		TestConfiguration.getCurrent().shutdownEngine();
        newValues = null;
        oldValues = null;
    }
    
    private void setProperties(Properties values)
        throws PrivilegedActionException
    {
    	for (Enumeration e = values.propertyNames(); e.hasMoreElements();)
    	{
    		String key = (String) e.nextElement();
    		String value = values.getProperty(key);
    		String old = BaseTestCase.getSystemProperty(key);
    		
    		boolean change;
    		if (old != null)
    		{
                // set, might need to be changed.
                change = !old.equals(value);
                
                // If we are not processing the oldValues
                // then store in the oldValues. Reference equality is ok here.
    			if (change && (values != oldValues))
    			   oldValues.setProperty(key, old);
    		}
    		else {
    			// notset, needs to be set
    			change = true;
    		}
    		
    		if (change) {
    			BaseTestCase.setSystemProperty(key, value);
    		}
    	}
    }
}