/**
 * 
 */
package org.csstudio.platform.internal.simpledal;

import org.csstudio.platform.model.pvs.IProcessVariableAddress;
import org.csstudio.platform.model.pvs.ValueType;

/**
 * Identifies a unique connector. A connector is unique by the process variable
 * it is connected to and the expected return type for values.
 * 
 * Connecting to the same process variable with a different expected return type
 * will result in a second physical connection.
 * 
 * Addressing characteristics does not lead to different connections - in fact
 * the same connector (with Object as expected return type) will be used for all
 * characteristics.
 * 
 * @author Sven Wende
 * 
 */
class ConnectorIdentification {
	private IProcessVariableAddress _processVariableAddress;
	private ValueType _valueType;

	/**
	 * Constructor.
	 * 
	 * @param processVariableAddress
	 *            the process variable address
	 * @param valueType
	 *            the expected return type
	 */
	public ConnectorIdentification(
			IProcessVariableAddress processVariableAddress, ValueType valueType) {
		assert processVariableAddress != null;
		assert valueType != null;
		_processVariableAddress = processVariableAddress
				.deriveNoCharacteristicPart();
		_valueType = valueType;
	}

	/**
	 * Returns the process variable address.
	 * 
	 * @return the process variable address
	 */
	public IProcessVariableAddress getProcessVariableAddress() {
		return _processVariableAddress;
	}

	/**
	 * The expected value type.
	 * 
	 * @return the expected value type
	 */
	public ValueType getValueType() {
		return _valueType;
	}

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

	/**
	 * {@inheritDoc}
	 */
	@Override
	public boolean equals(Object obj) {
		boolean result = false;

		if (obj != null && obj instanceof ConnectorIdentification) {
			ConnectorIdentification other = (ConnectorIdentification) obj;

			if (other._valueType == _valueType
					&& other._processVariableAddress
							.equals(_processVariableAddress)) {
				result = true;
			}
		}

		return result;
	}

}