package javax.megaco.message.descriptor;



import java.io.Serializable;





import javax.megaco.MethodInvocationException;

import javax.megaco.message.Descriptor;

import javax.megaco.message.DescriptorType;

import javax.megaco.message.Termination;



/**

 * The class extends JAIN MEGACO Descriptor. This class describes the mux

 * descriptor.

 */

public class MuxDescriptor extends Descriptor implements Serializable {



	private MuxType muxType;

	private Termination[] termList;

	private String extMux;



	/**

	 * Constructs a Mux Descriptor with the mux type and the termination id

	 * list.

	 * 

	 * @param muxType

	 *            - This specifies an object identifier of the mux type to be

	 *            specified for the mux descriptor.

	 * @param termList

	 *            - This specifies list of termination ids for the specified mux

	 *            type.

	 * @throws IllegalArgumentException

	 *             : This exception is raised if the reference of MuxType or

	 *             Termination Id list passed to this method is NULL.

	 */

	public MuxDescriptor(MuxType muxType, Termination[] termList) throws IllegalArgumentException {



		super.descriptorId = DescriptorType.M_MUX_DESC;



		if (muxType == null) {

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

		}



		if (termList == null) {

			throw new IllegalArgumentException("Termination[] must not be null");

		}



		if (termList.length == 0) {

			throw new IllegalArgumentException("Termination[] lmust not be empty");

		}



		this.muxType = muxType;

		this.termList = termList;

	}



	/**

	 * This method cannot be overridden by the derived class. This method

	 * returns that the descriptor identifier is of type Mux descriptor. This

	 * method overrides the corresponding method of the base class Descriptor.

	 * 

	 * @return Returns an integer value that identifies this object as the type

	 *         of Mux descriptor. It returns that it is Mux Descriptor i.e.,

	 *         M_MUX_DESC.

	 */

	public int getDescriptorId() {

		return super.descriptorId;

	}



	/**

	 * This method cannot be overridden by the derived class. This method

	 * returns the identity of the mux type. The constants for the mux type are

	 * defined in MuxType.

	 * 

	 * @return Returns value that identifies Mux type. It returns one of the

	 *         values defined in, MuxType.

	 */

	public final MuxType getMuxType() {

		return this.muxType;

	}



	/**

	 * This method returns the extension string of the mux type. The extension

	 * string should be prefixed with "X-" or "X+". The extension characters

	 * following the prefix should be at most of 6 characters. The extension

	 * string would be set only when the mux type specifies MUX_TYPE_EXTENSION.

	 * 

	 * @return Gets the string for the extension of the mux type. The extension

	 *         string would be set only when the mux type specifies

	 *         {@link MuxType.EXT}.

	 * @throws IllegalStateException

	 *             if the method has been called when the mux type denotes

	 *             anything other than {@link MuxType.EXT}.

	 */

	public java.lang.String getExtensionString() throws IllegalStateException {

		if (this.muxType.getMuxType() != muxType.M_EXT) {

			throw new IllegalStateException("MuxType must be: EXT");

		}

		return this.extMux;

	}



	/**

	 * Sets the string for the extension of the mux type. Should be set only

	 * when the mux type specifies MUX_TYPE_EXT.

	 * 

	 * @param extMux

	 *            - Sets the string for the extension of the mux type. The

	 *            extension string should be prefixed with "X-" or "X+". The

	 *            extension characters following the prefix should be at most of

	 *            6 characters. The extension string would be set only when the

	 *            mux type specifies {@link MuxType.EXT}.

	 * @throws IllegalArgumentException

	 *             if the extension string is not in proper format. It should be

	 *             prefixed with either "X+" or "X-" followed by at most 6

	 *             characters.

	 * @throws IllegalStateException

	 *             if the method has been called when the mux type denotes

	 *             anything other than {@link MuxType.EXT}.

	 */

	public void setExtensionString(java.lang.String extMux) throws IllegalArgumentException, IllegalStateException {



		if (this.muxType.getMuxType() != muxType.M_EXT) {

			throw new IllegalStateException("MuxType must be: EXT");

		}



		if (extMux == null) {

			new IllegalArgumentException("ExtMux must not be null");

		}



		DescriptorUtils.checkMethodExtensionRules(extMux);



		if (extMux.length() > 8) {

			throw new IllegalArgumentException("ExtMux must not be longer than 8 characters.");

		}

		this.extMux = extMux;



	}



	/**

	 * Gets the list of termination ids for which the mux type is specified.

	 * 

	 * @return Returns the list of termination ids for which the muxt type is

	 *         specified.

	 */

	public final Termination[] getTerminationIdList() {

		return this.termList;

	}



}