- plugin component listener and events were used only in the implementation, so I have moved them there

- Introduced PluginComponent interface to be implemented by all modules that would like add a component( button, menu item, etc.) in the gui.

src/net/java/sip/communicator/impl/gui/event/PluginComponentEvent.java

@@ -0,0 +1,70 @@
+/*
+ * SIP Communicator, the OpenSource Java VoIP and Instant Messaging client.
+ *
+ * Distributable under LGPL license.
+ * See terms of license at gnu.org.
+ */
+package net.java.sip.communicator.impl.gui.event;
+
+import java.awt.*;
+import java.util.*;
+
+import net.java.sip.communicator.service.gui.*;
+import net.java.sip.communicator.service.gui.Container;
+
+/**
+ * The <tt>PluginComponentEvent</tt> 
+ * @author Yana Stamcheva
+ */
+public class PluginComponentEvent
+    extends EventObject
+{
+
+    private int eventID = -1;
+
+    /**
+     * Indicates that the PluginComponentEvent instance was triggered by
+     * adding a plugin component.
+     */
+    public static final int PLUGIN_COMPONENT_ADDED = 1;
+
+    /**
+     * Indicates that the MetaContactEvent instance was triggered by the
+     * removal of an existing MetaContact.
+     */
+    public static final int PLUGIN_COMPONENT_REMOVED = 2;
+
+    /**
+     * Creates a new PluginComponentEvent according to the specified
+     * parameters.
+     * @param pluginComponent The pluginComponent that is added to the container.
+     * @param eventID one of the PLUGIN_COMPONENT_XXX static fields indicating
+     * the nature of the event.
+     */
+    public PluginComponentEvent(PluginComponent pluginComponent,
+                                int eventID)
+    {
+        super(pluginComponent);
+        this.eventID = eventID;
+    }
+
+    /**
+     * Returns the <tt>PluginComponent</tt> associated with this event.
+     * @return the <tt>PluginComponent</tt> associated with this event
+     */
+    public PluginComponent getPluginComponent()
+    {
+        return (PluginComponent) getSource();
+    }
+
+    /**
+     * Returns an event id specifying whether the type of this event 
+     * (PLUGIN_COMPONENT_ADDED or PLUGIN_COMPONENT_REMOVED)
+     * 
+     * @return one of the PLUGIN_COMPONENT_XXX int fields of this class.
+     */
+    public int getEventID()
+    {
+        return eventID;
+    }
+}

src/net/java/sip/communicator/impl/gui/event/PluginComponentListener.java

@@ -0,0 +1,33 @@
+/*
+ * SIP Communicator, the OpenSource Java VoIP and Instant Messaging client.
+ *
+ * Distributable under LGPL license.
+ * See terms of license at gnu.org.
+ */
+package net.java.sip.communicator.impl.gui.event;
+
+import java.util.*;
+/**
+ * Listens for all events caused by adding or removing of a plugin component.
+ * 
+ * @author Yana Stamcheva
+ */
+public interface PluginComponentListener 
+    extends EventListener {
+
+    /**
+     * Indicates that a plugin component has been successfully added
+     * to the container.
+     * @param event the PluginComponentEvent containing the corresponding
+     * plugin component
+     */
+    public void pluginComponentAdded(PluginComponentEvent event);
+    
+    /**
+     * Indicates that a plugin component has been successfully removed
+     * from the container.
+     * @param event the PluginComponentEvent containing the corresponding
+     * plugin component
+     */
+    public void pluginComponentRemoved(PluginComponentEvent event);
+}

src/net/java/sip/communicator/plugin/branding/AboutWindowPluginComponent.java

@@ -0,0 +1,61 @@
+/*
+ * SIP Communicator, the OpenSource Java VoIP and Instant Messaging client.
+ *
+ * Distributable under LGPL license.
+ * See terms of license at gnu.org.
+ */
+package net.java.sip.communicator.plugin.branding;
+
+import java.awt.event.*;
+
+import javax.swing.*;
+
+import net.java.sip.communicator.service.contactlist.*;
+import net.java.sip.communicator.service.gui.*;
+
+public class AboutWindowPluginComponent
+    implements PluginComponent
+{
+    private JMenuItem aboutMenuItem
+        = new JMenuItem(Resources.getString("aboutMenuEntry"));
+
+    public AboutWindowPluginComponent()
+    {
+        aboutMenuItem.addActionListener(new ActionListener()
+        {
+            public void actionPerformed(ActionEvent e)
+            {
+                AboutWindow aboutWindow = new AboutWindow(null);
+                aboutWindow.setVisible(true);
+            }
+        });
+    }
+
+    public Object getComponent()
+    {
+        return aboutMenuItem;
+    }
+
+    public String getConstraints()
+    {
+        return null;
+    }
+
+    public Container getContainer()
+    {
+        return Container.CONTAINER_HELP_MENU;
+    }
+
+    public String getName()
+    {
+        return Resources.getString("aboutMenuEntry");
+    }
+
+    public void setCurrentContact(MetaContact metaContact)
+    {
+    }
+
+    public void setCurrentContactGroup(MetaContactGroup metaGroup)
+    {
+    }
+}

src/net/java/sip/communicator/service/gui/PluginComponent.java

@@ -0,0 +1,89 @@
+/*
+ * SIP Communicator, the OpenSource Java VoIP and Instant Messaging client.
+ *
+ * Distributable under LGPL license.
+ * See terms of license at gnu.org.
+ */
+package net.java.sip.communicator.service.gui;
+
+import net.java.sip.communicator.service.contactlist.*;
+
+/**
+ * The <tt>PluginComponent</tt> is an interface meant to be implemented by
+ * all plugins that would like to add a user interface component to a particular
+ * container in the graphical user interface (GUI). In order to appear in the
+ * GUI all implementations of this interface should be registered through the
+ * OSGI bundle context.
+ * <p>
+ * All components interested in the current contact or group that they're
+ * dealing with (i.g. the one selected in the contact list for example), should
+ * implement the <tt>setCurrentContact</tt> and
+ * <tt>setCurrentContactGroup</tt> methods.
+ * <p>
+ * Note that <tt>getComponent</tt> should return a valid AWT, SWT or Swing
+ * control in order to appear properly in the GUI.
+ * 
+ * @author Yana Stamcheva
+ */
+public interface PluginComponent
+{
+    /**
+     * Returns the name of this plugin component. This name could be used as a
+     * label when the component is added to a container, which requires a title.
+     * A container that could request a name is for example a tabbed pane.
+     * 
+     * @return the name of this plugin component
+     */
+    public String getName();
+
+    /**
+     * Returns the identifier of the container, where we would like to add
+     * our control. All possible container identifiers are defined in the
+     * <tt>Container</tt> class. If the <tt>Container</tt> returned by this
+     * method is not supported by the current UI implementation the plugin won't
+     * be added.
+     * 
+     * @return the container, where we would like to add our control.
+     */
+    public Container getContainer();
+
+    /**
+     * Returns the constraints, which will indicate to the container, where this
+     * component should be added. All constraints are defined in the Container
+     * class and are as follows: START, END, TOP, BOTTOM, LEFT, RIGHT.
+     * 
+     * @return the constraints, which will indicate to the container, where this
+     * component should be added.
+     */
+    public String getConstraints();
+
+    /**
+     * Returns the component that should be added. This method should return a
+     * valid AWT, SWT or Swing object in order to appear properly in the user
+     * interface.
+     * 
+     * @return the component that should be added.
+     */
+    public Object getComponent();
+
+    /**
+     * Sets the current meta contact. Meant to be used by plugin components that
+     * are interested of the current contact. The current contact could be the
+     * contact currently selected in the contact list or the contact for the
+     * currently selected chat, etc. It depends on the container, where this
+     * component is meant to be added.
+     * 
+     * @param metaContact the current meta contact
+     */
+    public void setCurrentContact(MetaContact metaContact);
+
+    /**
+     * Sets the current meta group. Meant to be used by plugin components that
+     * are interested of the current meta group. The current group is always
+     * the currently selected group in the contact list. If the group passed
+     * here is null, this means that no group is selected.
+     * 
+     * @param metaGroup the current meta contact group
+     */
+    public void setCurrentContactGroup(MetaContactGroup metaGroup);
+}