gnu.cajo.invoke

Class JClient

java.lang.Object

java.awt.Component

java.awt.Container

java.awt.Panel

java.applet.Applet

javax.swing.JApplet

gnu.cajo.invoke.JClient

All Implemented Interfaces:

ImageObserver, MenuContainer, Serializable, Accessible, RootPaneContainer

public final class JClient
extends JApplet

This class is used to create a hosting VM to receive a Swing graphical proxy JComponent or and AWT Component, from a remote VM. The client will require one outbound port, on which to commuinicate with its proxy server and one on inbound, on which to receive asynchronous callbacks from the server, if required. It will also use one short-term inbound port on which to receive the proxy class files. If the client is behind a firewall, these will have to be open.

Note: to use this Client, instead of the default one, requires use of the new three argument CodebaseServer constructor. In this case, he third argument would need to be: "gnu.cajo.invoke.JClient".

Version:

1.0, 20-Feb-06 Initial release

Author:

John Catherino

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class javax.swing.JApplet

JApplet.AccessibleJApplet

Nested classes/interfaces inherited from class java.applet.Applet

Applet.AccessibleApplet

Nested classes/interfaces inherited from class java.awt.Panel

Panel.AccessibleAWTPanel

Nested classes/interfaces inherited from class java.awt.Container

Container.AccessibleAWTContainer

Nested classes/interfaces inherited from class java.awt.Component

Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy

Field Summary

Fields inherited from class javax.swing.JApplet

accessibleContext, rootPane, rootPaneCheckingEnabled

Fields inherited from class java.awt.Component

BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Fields inherited from interface java.awt.image.ImageObserver

ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH

Constructor Summary

Constructors

Constructor and Description
JClient() The default constructor does nothing.

Method Summary

Methods

Modifier and Type	Method and Description
void	destroy() This method is called from the AppleContext, when the JApplet is being disposed.
String	getAppletInfo() This method provides the standard mechanism to identify this JApplet.
String[][]	getParameterInfo() This method describes the optional client parameters.
void	init() This method connects back to its hosting server and requests the item from the server's rmiregistry.
static void	main(String[] args) The application creates a graphical Component proxy hosting VM.
void	start() This method is called from the AppleContext, each time the JApplet becomes visible.
void	stop() This method is called from the AppleContext, each time the JApplet becomes invisible.

Methods inherited from class javax.swing.JApplet

addImpl, createRootPane, getAccessibleContext, getContentPane, getGlassPane, getGraphics, getJMenuBar, getLayeredPane, getRootPane, getTransferHandler, isRootPaneCheckingEnabled, paramString, remove, repaint, setContentPane, setGlassPane, setJMenuBar, setLayeredPane, setLayout, setRootPane, setRootPaneCheckingEnabled, setTransferHandler, update

Methods inherited from class java.applet.Applet

getAppletContext, getAudioClip, getAudioClip, getCodeBase, getDocumentBase, getImage, getImage, getLocale, getParameter, isActive, isValidateRoot, newAudioClip, play, play, resize, resize, setStub, showStatus

Methods inherited from class java.awt.Panel

addNotify

Methods inherited from class java.awt.Container

add, add, add, add, add, addContainerListener, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getAlignmentX, getAlignmentY, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getComponentZOrder, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getInsets, getLayout, getListeners, getMaximumSize, getMinimumSize, getMousePosition, getPreferredSize, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paint, paintComponents, preferredSize, print, printComponents, processContainerEvent, processEvent, remove, removeAll, removeContainerListener, removeNotify, setComponentZOrder, setFocusCycleRoot, setFocusTraversalKeys, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setFont, transferFocusDownCycle, validate, validateTree

Methods inherited from class java.awt.Component

action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, createVolatileImage, createVolatileImage, disable, disableEvents, dispatchEvent, enable, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getBackground, getBaseline, getBaselineResizeBehavior, getBounds, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocation, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPeer, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, printAll, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, reshape, revalidate, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeysEnabled, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setName, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

JClient

public JClient()

The default constructor does nothing. Initialization is done when the JApplet is loaded into the browser.

Method Detail

getAppletInfo

public String getAppletInfo()

This method provides the standard mechanism to identify this JApplet.

Overrides:

getAppletInfo in class Applet

Returns:

The identification string for this JApplet.

getParameterInfo

public String[][] getParameterInfo()

This method describes the optional client parameters. There are five such parameters which can be specified:

• The proxyName parameter is the name of the proxy server item registered in the server's rmiregistry. Unspecified it will be "main".
• The proxyPort parameter is the outbound port number on which to contact the proxy server. Unspecified it will be 1099. If the client is operating behind a firewall, the must be a permitted outbound port.
• The clientHost parameter is the external domain name or IP address the server must use to callback its proxy. It may need to be specified if the client is operating behind a NAT router. Unspecified it will be the client's default host address.
• The clientPort parameter is the external inbound port number on which the server can contact its proxy. It may need to be specified if the client is behind NAT, to map to the correct local port. If a firewall is being used, it must be a permitted inbound port. Unspecified, it will be the same as the local port value below.
• The localPort parameter is the internal inbound port number on which the server can contact its proxy. It may need to be specified if the client is behind NAT, to map to the correct remote port. Unspecified, it will be anonymous.

Overrides:

getParameterInfo in class Applet

Returns:

The parameter / information array.

init

public void init()

This method connects back to its hosting server and requests the item from the server's rmiregistry. Next it will invoke a getProxy(null) on the remote reference to request its proxy item. If the item returns the proxy in a MarshalledObject, it will be extracted automatically. If the returned object is a proxy, the client will invoke its init method, passing it a remote reference itself, and to obtain its primary graphical Component representation, which will then be added into the JApplet via the Swing event dispatch thread. The proxy can pass this remote reference back to its hosting item, or to other remote items, on which they can asynchronously call it back.

Overrides:

init in class Applet

start

public void start()

This method is called from the AppleContext, each time the JApplet becomes visible. It will attempt to invoke a no-arg start method on the proxy, in the event that it supports one. Support of the method by the proxy is optional.

Overrides:

start in class Applet

stop

public void stop()

This method is called from the AppleContext, each time the JApplet becomes invisible. It will attempt to invoke a no-arg stot method on the proxy, in the event that it supports one. Support of the method by the proxy is optional.

Overrides:

stop in class Applet

destroy

public void destroy()

This method is called from the AppleContext, when the JApplet is being disposed. It will attempt to invoke a no-arg destroy method on the proxy, in the event that it supports one. Support of the method by the proxy is optional.

Overrides:

destroy in class Applet

main

public static void main(String[] args)
                 throws Exception

The application creates a graphical Component proxy hosting VM. With the URL argument provided, it will use the static getItem method of the Remote class to contact the server. It will then invoke a null-argument getProxy on the resulting reference to request the primary proxy object of the item.

When using the JClient from the command line, it is possible to set the JClient frame title explicitly. To do this, simply type:

java -cp cajo.jar -Dgnu.cajo.invoke.JClient.title="My Frame Title" gnu.cajo.invoke.JClient //myHost:1198/test

Note: When running as an application (except via WebStart) it will load a NoSecurityManager, therefore, if no external SecurityManager is specified in the startup command line; the arriving proxies will have full permissions on this machine!

To restrict client proxies permissions, use a startup invocation similar to the following:

java -cp cajo.jar -Djava.security.manager -Djava.security.policy=client.policy ... gnu.cajo.invoke.JClient ...

See the project client documentation, for more details.

The startup requires one mandatory, and up to four optional configuration parameters, in this order:

• args[0] - The URL where to get the graphical proxy item:
  file:// http:// ftp:// ..., //host:port/name (rmiregistry), /path/name (serialized), or path/name (class).
• args[1] - The optional external client port number, if using NAT.
• args[2] - The optional external client host name, if using NAT.
• args[3] - The optional internal client port number, if using NAT.
• args[4] - The optional internal client host name, if multi home/NIC.

Throws:

Exception