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The JavaHelp API provides a platform-independent help framework.
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/*
* @(#)DefaultHelpHistoryModel.java 1.4 06/10/30
*
* Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun in the LICENSE file that accompanied this code.
*
* 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 General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package javax.help;
import java.beans.*;
import java.util.Vector;
import javax.help.event.*;
import javax.help.Map.ID;
import java.util.Enumeration;
import java.net.URL;
import java.util.Stack;
/**
* DefaultHelpHistoryModel is default implementation of HelpHistoryModel interface
*
* @author Richard Gregor
* @version 1.4 10/30/06
*/
public class DefaultHelpHistoryModel implements HelpHistoryModel{
protected Vector history = new Vector();
protected int historyIndex = -1;
protected HelpModel helpModel;
protected EventListenerList listenerList = new EventListenerList();
protected JHelp help;
/**
* Creates new DefaultHelpHistoryModel for given JHelp
*
* @param help The JHelp
*/
public DefaultHelpHistoryModel(JHelp help) {
this.help = help;
if (help != null){
setHelpModel(help.getModel());
}
}
/**
* Sets a new HelpModel
*
* @param model The new HelpModel
*/
public void setHelpModel(HelpModel model){
if(model == helpModel)
return;
else
discard();
if(helpModel != null)
helpModel.removeHelpModelListener(this);
if(model != null)
model.addHelpModelListener(this);
helpModel = model;
}
/**
* Removes a listener previously added with addHelpHistoryModelListener
*
* @param l The listener to remove.
* @see javax.help.HelpHistoryModel#addHelpHistoryModelListener
*/
public void removeHelpHistoryModelListener(HelpHistoryModelListener l) {
listenerList.remove(HelpHistoryModelListener.class, l);
}
/**
* Adds a listener for the HelpHistoryModelEvent posted after the model has
* changed.
*
* @param l The listener to add.
* @see javax.help.HelpHistoryModel#removeHelpHistoryModelListener
*/
public void addHelpHistoryModelListener(HelpHistoryModelListener l) {
listenerList.add(HelpHistoryModelListener.class, l);
}
/**
* Discards a history
*/
public void discard() {
history.setSize(0);
historyIndex = -1;
fireHistoryChanged(this,false,false);
}
/**
* Returns a history
*
* @return The vector of history entries
*/
public Vector getHistory(){
return history;
}
/**
* Removes the last history entry
*
*/
public void removeLastEntry(){
int size = history.size();
if(size > 0)
history.removeElementAt(history.size() -1);
}
/**
* Returns a current history position
*
* @return The history index
*/
public int getIndex(){
return historyIndex;
}
/**
* Sets the next history entry
*/
public void goForward(){
setHistoryEntry(historyIndex+1);
}
/**
* Sets the previous histroy entry
*/
public void goBack(){
setHistoryEntry(historyIndex-1);
}
/**
* Returns a forward history vector
*
* @return The vector of forward history entries
*/
public Vector getForwardHistory() {
Vector historyCopy = (Vector)history.clone();
Vector forwardHistory = new Vector();
int size = historyCopy.size();
debug(" forward size : "+size);
for(int i = historyIndex + 1 ; i < size; i++){
forwardHistory.addElement(historyCopy.elementAt(i));
}
return forwardHistory;
}
/**
* Returns a backward history vector
*
* @return The vector of backward history entries
*/
public Vector getBackwardHistory() {
Vector backwardHistory = new Vector();
Vector historyCopy = (Vector)history.clone();
debug(" backward size : "+historyCopy.size());
debug(" backward index : "+historyIndex);
if(historyCopy != null){
for(int i = 0 ; i < historyIndex; i++){
backwardHistory.addElement(historyCopy.elementAt(i));
}
}
return backwardHistory;
}
/**
* Sets the current history entry
*
* @param index The index of history entry
*/
public void setHistoryEntry(int index) {
debug("setHistoryEntry("+index+")");
if (helpModel == null) {
return;
}
if (index < 0 || index >= history.size()) {
// invalid index
discard();
return;
}
HelpModelEvent e = (HelpModelEvent) history.elementAt(index);
// set the historyIndex so it is ready to take the next event...
historyIndex = index-1;
ID id = e.getID();
URL url = e.getURL();
JHelpNavigator navigator = e.getNavigator();
if (id != null) {
// try to set the ID
try {
debug(" setCurrentID"+id);
helpModel.setCurrentID(id, e.getHistoryName(),e.getNavigator());
if(navigator != null)
help.setCurrentNavigator(navigator);
return;
} catch (Exception ex) {
// fall through
}
}
if (url != null) {
// try to set the URL
try {
debug(" setCurrentURL"+url);
helpModel.setCurrentURL(url,e.getHistoryName(),e.getNavigator());
if(navigator != null)
help.setCurrentNavigator(navigator);
return;
} catch (Exception ex) {
// fall through
}
}
// this really should not happen but...
discard();
}
/**
* Fires the history change
*/
protected void fireHistoryChanged(Object source, boolean previous, boolean next) {
Object[] listeners = listenerList.getListenerList();
HelpHistoryModelEvent e = null;
for (int i = listeners.length - 2; i >= 0; i -= 2) {
if (listeners[i] == HelpHistoryModelListener.class) {
if (e == null) {
e = new HelpHistoryModelEvent(source, previous, next);
}
debug("fireHistoryChanged: ");
debug(" "+listeners[i+1]);
debug(" previous="+e.isPrevious() + " next="+e.isNext());
((HelpHistoryModelListener)listeners[i+1]).historyChanged(e);
}
}
}
/**
* Tells the listener that the current ID in the HelpModel has
* changed.
* All highlights from the previous location change at this point.
*
* @param e The event
*/
public void idChanged(HelpModelEvent e) {
debug("idChanged("+e+")");
debug(" historyIndex=="+historyIndex);
debug(" history.size=="+history.size());
if (historyIndex == history.size()-1) {
// we are at the end
// (this covers the initial case of historyIndex == -1
history.addElement(e);
historyIndex += 1;
fireHistoryChanged(this,(historyIndex > 0),(historyIndex < history.size()-1));
return;
}
if (historyIndex >= -1 &&
historyIndex < history.size()-1) {
// check the next slot where to record
historyIndex += 1; // advance
HelpModelEvent h
= (HelpModelEvent) history.elementAt(historyIndex);
if (h == null) {
// this really should not happen
discard();
return;
}
// compare ID's first
if (h.getID() != null && e.getID() != null &&
h.getID().equals(e.getID())) {
// we are were we wanted to be, just return
fireHistoryChanged(this,(historyIndex > 0),(historyIndex < history.size()-1));
return;
}
// compare URL's now
if (h.getURL() != null && e.getURL() != null &&
h.getURL().sameFile(e.getURL())) {
// we are were we wanted to be, just return
fireHistoryChanged(this,(historyIndex > 0),(historyIndex < history.size()-1));
return;
}
// new location is different, so throw away object and the rest
history.setSize(historyIndex);
// add the new element
history.addElement(e);
fireHistoryChanged(this,(historyIndex > 0),(historyIndex < history.size()-1));
}
}
/**
* Removes entries related to removed HelpSet from history
*
* @param hs The removed HelpSet
*/
public void removeHelpSet(HelpSet hs){
Enumeration e = history.elements();
debug(" size before " +history.size());
if(debug){
System.err.println("before : ");
for(int j = 0; j < history.size(); j++){
System.err.println(((HelpModelEvent)history.elementAt(j)).getID());
}
}
int size = history.size();
Vector newHistory = new Vector();
int index = historyIndex;
for(int i = 0; i < size; i++){
HelpModelEvent evt = (HelpModelEvent)history.elementAt(i);
ID id = evt.getID();
debug(" update id "+id);
URL url = evt.getURL();
debug(" update url " +url);
if ((id != null) && (id.hs != hs)) {
debug(" remain - "+id);
newHistory.addElement(history.elementAt(i));
}
else if (url != null) {
//find out if there is a matching ID for this URL
ID idcan = hs.getCombinedMap().getIDFromURL(url);
if(idcan == null){
debug(" remain > "+idcan);
newHistory.addElement(history.elementAt(i));
}
}
}
history = newHistory;
historyIndex = history.size() -1;
debug(" size after " + history.size());
if(debug){
System.err.println("after : ");
for(int j = 0; j < history.size(); j++){
System.err.println(((HelpModelEvent)history.elementAt(j)).getID());
}
}
setHistoryEntry(historyIndex);
//computeHistoryButtons();
}
/**
* Returns HelpModel
*
* @return The HelpModel
*/
protected HelpModel getModel(){
return helpModel;
}
/**
* For printf debugging.
*/
private static boolean debug = false;
private static void debug(String str) {
if (debug) {
System.out.println("BasicHelpUI: " + str);
}
}
}
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