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VCAFE.3.0A
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InvisibleHTMLLink.java
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1998-08-21
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package symantec.itools.awt;
import java.net.URL;
import java.awt.Container;
import java.applet.*;
import java.beans.PropertyVetoException;
import java.beans.PropertyChangeListener;
import java.beans.VetoableChangeListener;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
// 06/11/97 LAB Updated to Java 1.1.
// 07/18/97 LAB Added add/removeNotify to handle event listener registration.
// 07/29/97 CAR marked fields transient as needed
// inner adaptor class implements java.io.Serializable
// 08/18/97 CAR moved code to locate containing Applet into addNotify
// 08/21/97 LAB Updated so when the mouse enters, the HTML link is displayed in the
// status area of the browser/viewer. Added a check in the action event
// handling code to look for a null url. Apparently context.showDocument()
// would silently throw, causing the action event to be eaten if it was passed
// a null url. Addresses Mac Bug #7436
/**
* Use this component to create an invisible rectangular button, usually within
* an image, that displays the document at a given URL when clicked.
* @version 1.1, June 11, 1997
* @author Symantec
*/
public class InvisibleHTMLLink extends InvisibleButton
{
/**
* Constructs a default InvisibleHTMLLink.
*/
public InvisibleHTMLLink()
{
frame = null;
url = null;
context = null;
}
/**
* Sets the URL of the document to show when the button is clicked.
* @param u the URL
* @exception PropertyVetoException
* if the specified property value is unacceptable
* @see #getURL
*/
public void setURL(URL u) throws PropertyVetoException
{
if(!symantec.itools.util.GeneralUtils.objectsEqual(url, u))
{
URL oldValue = url;
vetos.fireVetoableChange("URL", oldValue, u);
url = u;
context = null;
changes.firePropertyChange("URL", oldValue, u);
}
}
/**
* Returns the URL of the document to show when the button is clicked.
* @see #setURL
*/
public URL getURL()
{
return url;
}
/**
* Sets the frame specifier for showing a URL document in a browser or applet
* viewer. It is interpreted as follows:
* <UL>
* <DT>"_self" show document in the current frame</DT>
* <DT>"_parent" show document in the parent frame</DT>
* <DT>"_top" show document in the topmost frame</DT>
* <DT>"_blank" show document in a new unnamed toplevel window</DT>
* <DT>all others show document in a new toplevel window with the given name</DT>
* </UL>
* @param f the frame specifier
* @see #getFrame
* @see symantec.itools.util.GeneralUtils#frameTarget_self
* @see symantec.itools.util.GeneralUtils#frameTarget_parent
* @see symantec.itools.util.GeneralUtils#frameTarget_top
* @see symantec.itools.util.GeneralUtils#frameTarget_blank
* @exception PropertyVetoException
* if the specified property value is unacceptable
*/
public void setFrame(String f) throws PropertyVetoException
{
String oldValue = frame;
vetos.fireVetoableChange("Frame", oldValue, f);
frame = f;
changes.firePropertyChange("Frame", oldValue, f);
}
/**
* Gets the frame specifier for showing a URL document in a browser or applet
* viewer. It is interpreted as follows:
* <UL>
* <DT>"_self" show document in the current frame</DT>
* <DT>"_parent" show document in the parent frame</DT>
* <DT>"_top" show document in the topmost frame</DT>
* <DT>"_blank" show document in a new unnamed toplevel window</DT>
* <DT>all others show document in a new toplevel window with the given name</DT>
* </UL>
* @return the frame specifier
* @see #setFrame
*/
public String getFrame()
{
return frame;
}
/**
* Tells this component that it has been added to a container.
* This is a standard Java AWT method which gets called by the AWT when
* this component is added to a container. Typically, it is used to
* create this component's peer.
*
* It has been overridden here to hook-up event listeners.
*
* @see #removeNotify
*/
public synchronized void addNotify()
{
super.addNotify();
//Hook up listeners
if (action == null)
{
action = new Action();
addActionListener(action);
}
if (mouse == null)
{
mouse = new Mouse();
addMouseListener(mouse);
}
// On addNotify, try to find the containing applet.
Container c = getParent();
while (c != null)
{
if (c instanceof Applet)
{
setAppletContext(((Applet) c).getAppletContext());
break;
}
c = c.getParent();
}
}
/**
* Tells this component that it is being removed from a container.
* This is a standard Java AWT method which gets called by the AWT when
* this component is removed from a container. Typically, it is used to
* destroy the peers of this component and all its subcomponents.
*
* It has been overridden here to unhook event listeners.
*
* @see #addNotify
*/
public synchronized void removeNotify()
{
//Unhook listeners
if (action != null)
{
removeActionListener(action);
action = null;
}
if (mouse != null)
{
removeMouseListener(mouse);
mouse = null;
}
super.removeNotify();
}
/**
* Adds a listener for all event changes.
* @param PropertyChangeListener listener the listener to add.
* @see #removePropertyChangeListener
*/
public synchronized void addPropertyChangeListener(PropertyChangeListener listener)
{
super.addPropertyChangeListener(listener);
changes.addPropertyChangeListener(listener);
}
/**
* Removes a listener for all event changes.
* @param PropertyChangeListener listener the listener to remove.
* @see #addPropertyChangeListener
*/
public synchronized void removePropertyChangeListener(PropertyChangeListener listener)
{
super.removePropertyChangeListener(listener);
changes.removePropertyChangeListener(listener);
}
/**
* Adds a vetoable listener for all event changes.
* @param VetoableChangeListener listener the listener to add.
* @see #removeVetoableChangeListener
*/
public synchronized void addVetoableChangeListener(VetoableChangeListener listener)
{
super.addVetoableChangeListener(listener);
vetos.addVetoableChangeListener(listener);
}
/**
* Removes a vetoable listener for all event changes.
* @param VetoableChangeListener listener the listener to remove.
* @see #addVetoableChangeListener
*/
public synchronized void removeVetoableChangeListener(VetoableChangeListener listener)
{
super.removeVetoableChangeListener(listener);
vetos.removeVetoableChangeListener(listener);
}
/**
* This is the Mouse Event handling innerclass.
*/
class Mouse extends java.awt.event.MouseAdapter
{
boolean statusChanged = false;
/**
* Handles Mouse Entered events
* @param e the MouseEvent
*/
public void mouseEntered(MouseEvent e)
{
if(context != null && url != null)
{
statusChanged = true;
context.showStatus(url.toString());
}
}
/**
* Handles Mouse Exited events
* @param e the MouseEvent
*/
public void mouseExited(MouseEvent e)
{
if(context != null && statusChanged)
{
statusChanged = false;
context.showStatus("");
}
}
}
/**
* This is the Adjustment Event handling innerclass.
*/
class Action implements java.awt.event.ActionListener, java.io.Serializable
{
/**
* Handles Action events
* @param e the ActionEvent
*/
public void actionPerformed(ActionEvent e)
{
if (context != null && url != null)
{
if (frame == null || frame.length() == 0)
context.showDocument(url);
else
context.showDocument(url, frame);
}
}
}
/**
* Sets the applet context used to view documents.
* @param c the new applet context
*/
protected void setAppletContext(AppletContext c)
{
context = c;
}
/**
* The URL of the document to show when the button is clicked.
*/
protected URL url;
/**
* Applet context that shows the document.
*/
transient protected AppletContext context;
/**
* Frame specifier for showing a URL document in a browser or applet
* viewer. It is interpreted as follows:
* <UL>
* <DT>"_self" show document in the current frame</DT>
* <DT>"_parent" show document in the parent frame</DT>
* <DT>"_top" show document in the topmost frame</DT>
* <DT>"_blank" show document in a new unnamed toplevel window</DT>
* <DT>all others show document in a new toplevel window with the given name</DT>
* </UL>
*/
protected String frame;
// Private members
private Action action = null;
private Mouse mouse = null;
private symantec.itools.beans.VetoableChangeSupport vetos = new symantec.itools.beans.VetoableChangeSupport(this);
private symantec.itools.beans.PropertyChangeSupport changes = new symantec.itools.beans.PropertyChangeSupport(this);
}