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package net.sf.fmj.media;

import javax.media.*;
import javax.media.control.*;
import javax.media.protocol.*;

/**
 * BasicProcessor implements the bases of a javax.media.Processor. It handles
 * all the Processor state transitions, event handling and management of any
 * Controller under its control.
 */

public abstract class BasicProcessor extends BasicPlayer implements Processor
{
    static String NOT_CONFIGURED_ERROR = "cannot be called before the Processor is configured";

    /**
     * Return the output content-type.
     *
     * @return The current output content-type.
     * @exception NotConfiguredError
     *                if the Processor is Unrealized.
     */
    public ContentDescriptor getContentDescriptor() throws NotConfiguredError
    {
        if (getState() < Processor.Configured)
            throw new NotConfiguredError("getContentDescriptor "
                    + NOT_CONFIGURED_ERROR);
        return null;
    }

    /**
     * Return the output DataSource of the Processor. The output DataSource is
     * the output connection of the Processor through which it supplies the
     * processed streams.
     *
     * @return The output DataSource of the Processor.
     * @exception NotRealizedError
     *                if the Processor is not realized.
     */
    public DataSource getDataOutput() throws NotRealizedError
    {
        if (getState() < Realized)
            throw new NotRealizedError(
                    "getDataOutput cannot be called before the Processor is realized");
        return null;
    }

    /**
     * Return all the content-types which this Processor's output supports. The
     * Processor builds the ContentDescriptor array according to the
     * input DataSource attached to the Processor and according to the codecs
     * and multiplexers installed in the system.
     *
     * @return An array of the the content-types supported by the Processor.
     * @exception NotConfiguredError
     *                if the Processor is Unrealized.
     */
    public ContentDescriptor[] getSupportedContentDescriptors()
            throws NotConfiguredError
    {
        if (getState() < Processor.Configured)
            throw new NotConfiguredError("getSupportedContentDescriptors "
                    + NOT_CONFIGURED_ERROR);
        return new ContentDescriptor[0];
    }

    /**
     * Return the tracks in the media. This method can only be called after the
     * Processor has been configured. A NotConfiguredError is thrown if
     * getTrackControls is called and the Processor is in the
     * Unrealized or Configuring states.
     *
     * @return An array of the tracks in the media. An emtpy array is returned
     *         if there is no TrackControl available for this
     *         Processor.
     * @exception NotConfiguredError
     *                if the Processor is Unrealized.
     */
    public TrackControl[] getTrackControls() throws NotConfiguredError
    {
        if (getState() < Processor.Configured)
            throw new NotConfiguredError("getTrackControls "
                    + NOT_CONFIGURED_ERROR);
        return new TrackControl[0];
    }

    /**
     * A processor is configurable.
     */
    @Override
    protected boolean isConfigurable()
    {
        return true;
    }

    /**
     * Set the output content-type. If setContentDescriptor is not
     * called, the output DataSource's output will be on individual tracks.
     *
     * @param ocd the content-type of the output.
     * @exception NotConfiguredError if the Processor is Unrealized. realized
     * state and it does not support format changes after it has been realized.
     */
    public ContentDescriptor setContentDescriptor(ContentDescriptor ocd)
            throws NotConfiguredError
    {
        if (getState() < Processor.Configured)
            throw new NotConfiguredError("setContentDescriptor "
                    + NOT_CONFIGURED_ERROR);
        return ocd;
    }

}