package javax.megaco.message.descriptor;



import java.io.Serializable;





import javax.megaco.MethodInvocationException;

import javax.megaco.pkg.PkgEventItem;

import javax.megaco.pkg.PkgItemStr;



/**

 * The ObservedEvent object is a class that shall be used to set the observed

 * events and the stream id in which it was observed along with optionally the

 * time at which it was detected. The class optionally provides interface to

 * specify the package name, item name and the associated parameters in the

 * string format. This is an independent class derived from java.util.Object and

 * shall not have any derived classes.

 */

public class ObservedEvent implements Serializable {



	private PkgEventItem eventItem;

	private PkgItemStr eventItemStr;

	private TimeStamp timeStamp;

	private Integer streamId;



	/**

	 * Constructs Observed Event parameter Object. This is to be set within an

	 * observed event descriptor.

	 * 

	 * @param eventItem

	 * @throws IllegalArgumentException

	 *             - Thrown if an invalid event id is set.

	 */

	public ObservedEvent(PkgEventItem eventItem) throws IllegalArgumentException {



		// FIXME: add error check on invalid event?

		if (eventItem == null) {

			throw new IllegalArgumentException("PkgEventItem must not be null");



		}



		this.eventItem = eventItem;

	}



	/**

	 * 

	 * Constructs Observed Event parameter object with the PkgItemStr object.

	 * This method would be used if the package parameters are to be conveyed in

	 * the string format. This is to be set within an event buffer descriptor.

	 * 

	 * @param eventItemStr

	 * @throws IllegalArgumentException

	 *             - Thrown if an invalid eventItemStr object reference is set.

	 */

	public ObservedEvent(PkgItemStr eventItemStr) throws IllegalArgumentException {

		if (eventItemStr == null) {

			throw new IllegalArgumentException("PkgItemStr must not be null");



		}



		this.eventItemStr = eventItemStr;

	}



	/**

	 * The method can be used to get the pkdgName as set in the observed event

	 * descriptor. This method gives the package information, the attached event

	 * information and the parameter name and value for the event id.

	 * 

	 * @return The object reference for the megaco package, which has the object

	 *         reference for megaco package event and which in turn has the

	 *         reference for the parameter info. If the parameter has not been

	 *         set, then this method shall return NULL.

	 */

	public PkgEventItem getMegacoPkgEvtItem() {

		return this.eventItem;



	}



	/**

	 * The method can be used to get the pkdgName as set in the observed event

	 * descriptor. This method gives the package information, the attached event

	 * information and the parameter name and value. As compares to the

	 * getMegacoPkgEvtItem() method, this method returns the package parameters

	 * in the string format.

	 * 

	 * @return The object reference for the megaco package item. This class

	 *         holds information about package name, item name and the

	 *         parameters in the string format. If the parameter has not been

	 *         set, then this method shall return NULL.

	 */

	public PkgItemStr getMegacoPkgItemStr() {

		return this.eventItemStr;

	}



	/**

	 * The method can be used to get stream id in the event descriptor.

	 * 

	 * @return streamId - The integer value of the stream id shall be returned.

	 *         This shall be returned only if the streamId is present in the

	 *         event parameter of the event descriptor.

	 * @throws IllegalStateException

	 *             - Thrown if streamId has not been set. Thus this method

	 *             should be called only after verifying that the streamId is

	 *             set using isStreamIdPresent

	 */

	public int getStreamId() throws IllegalStateException {

		if (!isStreamIdPresent()) {

			throw new IllegalStateException("StreamId must be present");

		}

		return this.streamId.intValue();

	}



	/**

	 * The method can be used to set stream id in the event descriptor. This

	 * automatically sets the value of stream id present in the event parameter

	 * object to true.

	 * 

	 * @param streamId

	 *            - The integer value of the stream id shall be set.

	 * @throws IllegalArgumentException

	 *             - Thrown if streamId is set with an invalid value.

	 */

	public void setStreamId(int streamId) throws IllegalArgumentException {

		if (streamId <= 0) {

			throw new IllegalArgumentException("StreamId must be greater than zero.");

		}

		this.streamId = new Integer(streamId);

	}



	/**

	 * The method can be used to find if the stream id is present in the current

	 * object.

	 * 

	 * @return Returns true if the stream id is present. This needs to be

	 *         checked before getting the stream id from this object.

	 */

	public boolean isStreamIdPresent() {

		return this.streamId != null;

	}



	/**

	 * The method is used to retrieve the time stamp at which the event was

	 * detected.

	 * 

	 * @return timeStamp - The object reference for the timestamp. It returns a

	 *         NULL value when not set.

	 */

	public TimeStamp getTimeStamp() {

		return this.timeStamp;

	}



	/**

	 * The method is used to set the time stamp at which the event was detected.

	 * 

	 * @param timeStamp

	 *            - The object reference for the timestamp.

	 * @throws IllegalArgumentException

	 *             - Thrown if timestamp is set with an invalid value.

	 */

	public void setTimeStamp(TimeStamp timeStamp) throws IllegalArgumentException {



		// FIXME: add checks for invalid value?

		if (timeStamp == null) {

			throw new IllegalArgumentException("TimeStamp must not be null");

		}



		this.timeStamp = timeStamp;

	}



	public java.lang.String toString() {

		return super.toString();

	}



}