ParameterDescriptor.java

/* 
 * Copyright (c) 2006 Stiftung Deutsches Elektronen-Synchroton, 
 * Member of the Helmholtz Association, (DESY), HAMBURG, GERMANY.
 *
 * THIS SOFTWARE IS PROVIDED UNDER THIS LICENSE ON AN "../AS IS" BASIS. 
 * WITHOUT WARRANTY OF ANY KIND, EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED 
 * TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR PARTICULAR PURPOSE AND 
 * NON-INFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE 
 * FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR 
 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. SHOULD THE SOFTWARE PROVE DEFECTIVE 
 * IN ANY RESPECT, THE USER ASSUMES THE COST OF ANY NECESSARY SERVICING, REPAIR OR 
 * CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS LICENSE. 
 * NO USE OF ANY SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER THIS DISCLAIMER.
 * DESY HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, 
 * OR MODIFICATIONS.
 * THE FULL LICENSE SPECIFYING FOR THE SOFTWARE THE REDISTRIBUTION, MODIFICATION, 
 * USAGE AND OTHER RIGHTS AND OBLIGATIONS IS INCLUDED WITH THE DISTRIBUTION OF THIS 
 * PROJECT IN THE FILE LICENSE.HTML. IF THE LICENSE IS NOT INCLUDED YOU MAY FIND A COPY 
 * AT HTTP://WWW.DESY.DE/LEGAL/LICENSE.HTM
 */
package org.csstudio.sds.internal.rules;

import java.util.Map;

import org.csstudio.platform.model.pvs.IProcessVariableAddress;
import org.csstudio.platform.model.pvs.ProcessVariableAdressFactory;
import org.csstudio.sds.util.ChannelReferenceValidationException;
import org.csstudio.sds.util.ChannelReferenceValidationUtil;

/**
 * A description of rule parameters.
 * 
 * @author Alexander Will & Sven Wende
 * @version $Revision: 1.3 $
 * 
 */
public final class ParameterDescriptor {
	/**
	 * The name of the channel.
	 */
	private String _channel;

	/**
	 * The default value.
	 */
	private String _value = "";
	
	/**
	 * Constructs a default parameter with an empty channel name and type
	 * Double.class.
	 * 
	 */
	public ParameterDescriptor() {
		this("", ""); //$NON-NLS-1$
	}


	/**
	 * Standard constructor.
	 * 
	 * @param channel
	 *            The name of the channel, respectively process variable.
	 * @param type
	 *            The type of the expected data.
	 * @param value
	 * 			  The default value.
	 */
	public ParameterDescriptor(final String channel, final String value) {
		assert channel != null : "channel != null";
		assert value != null : "value != null";
		
		_channel = channel;
		_value = value;
	}

	public ParameterDescriptor(String channel) {
		this(channel, "");
	}

	/**
	 * Return the name of the channel, respectively process variable.
	 * 
	 * @return The name of the channel, respectively process variable.
	 */
	public String getChannel() {
		return _channel;
	}

	private boolean isChannelSpecified() {
		return _channel!=null && _channel.trim().length()>0;
	}
	
	public IProcessVariableAddress getPv(final Map<String, String> aliases) {
		IProcessVariableAddress result = null;

		if (isChannelSpecified()) {
			try {
				String realName = ChannelReferenceValidationUtil.createCanonicalName(getChannel(), aliases);
				result = ProcessVariableAdressFactory.getInstance().createProcessVariableAdress(realName);
			} catch (ChannelReferenceValidationException e) {
				result = null;
			}
		}

		return result;
	}
	
	/**
	 * Set the name of the channel, respectively process variable.
	 * 
	 * @param channel
	 *            The name of the channel, respectively process variable.
	 */
	public void setChannel(final String channel) {
		_channel = channel;
	}

	/**
	 * Return the default value.
	 * 
	 * @return The default value.
	 */
	public String getValue() {
		return _value;
	}

	/**
	 * Set the default value.
	 * 
	 * @param value
	 *            The default value.
	 */
	public void setValue(final String value) {
		assert value != null : "value != null";
		
		_value = value;
	}
	
	/**
	 * {@inheritDoc}
	 */
	@Override
	public String toString() {
		return _channel;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public ParameterDescriptor clone() {
		return new ParameterDescriptor(new String(_channel), _value);
	}

	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result
				+ ((_channel == null) ? 0 : _channel.hashCode());
		result = prime * result + ((_value == null) ? 0 : _value.hashCode());
		return result;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		ParameterDescriptor other = (ParameterDescriptor) obj;
		if (_channel == null) {
			if (other._channel != null)
				return false;
		} else if (!_channel.equals(other._channel))
			return false;
		if (_value == null) {
			if (other._value != null)
				return false;
		} else if (!_value.equals(other._value))
			return false;
		return true;
	}

}