/*
* Copyright (c) 2007, 2008 Wayne Meissner
* Copyright (C) 2004 Wim Taymans <wim@fluendo.com>
*
* This file is part of gstreamer-java.
*
* This code is free software: you can redistribute it and/or modify it under
* the terms of the GNU Lesser General Public License version 3 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* version 3 for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* version 3 along with this work. If not, see <http://www.gnu.org/licenses/>.
*/
package org.freedesktop.gstreamer;
import org.freedesktop.gstreamer.lowlevel.GstMessageAPI;
import org.freedesktop.gstreamer.lowlevel.ReferenceManager;
import org.freedesktop.gstreamer.lowlevel.annotations.HasSubtype;
import static org.freedesktop.gstreamer.lowlevel.GstMessageAPI.GSTMESSAGE_API;
/**
* Lightweight objects to signal the occurrence of pipeline events.
*
* <p> Messages are implemented as a subclass of {@link MiniObject} with a generic
* {@link Structure} as the content. This allows for writing custom messages without
* requiring an API change while allowing a wide range of different types
* of messages.
*
* <p> Messages are posted by objects in the pipeline and are passed to the
* application using the {@link Bus}.
* The basic use pattern of posting a message on a Bus is as follows:
*
* <example>
* <title>Posting a Message</title>
* <code>
* bus.post(new EOSMessage(source));
* </code>
* </example>
*
* An {@link Element} usually posts messages on the bus provided by the parent
* container using {@link Element#postMessage postMessage()}.
*/
@HasSubtype
public class Message extends MiniObject {
public static final String GTYPE_NAME = "GstMessage";
protected GstMessageAPI.MessageStruct messageStruct;
/**
* Creates a new instance of Message.
*
* @param init internal initialization data.
*/
public Message(Initializer init) {
super(init);
messageStruct = new GstMessageAPI.MessageStruct(handle());
}
/**
* Gets the Element that posted this message.
*
* @return the element that posted the message.
*/
public GstObject getSource() {
return (GstObject)messageStruct.readField("src");
}
/**
* Gets the structure containing the data in this message.
*
* @return a structure.
*/
public Structure getStructure() {
return ReferenceManager.addKeepAliveReference(GSTMESSAGE_API.gst_message_get_structure(this), this);
}
/**
* Gets the type of this message.
*
* @return the message type.
*/
public MessageType getType() {
MessageType type = (MessageType)messageStruct.readField("type");
return type;
}
}