net.sf.juife.swing.DefaultNavigationHistoryModel Maven / Gradle / Ivy
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/*
* juife - Java User Interface Framework Extensions
*
* Copyright (C) 2005-2007 Grigor Iliev
*
* This file is part of juife.
*
* juife is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1 as published by the Free Software Foundation.
*
* juife 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 for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with juife; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA
*/
package net.sf.juife.swing;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.LinkedList;
import java.util.ListIterator;
import java.util.Vector;
/**
* Provides default implementation of the NavigationHistoryModel interface.
* Note that this implementation of {@link NavigationHistoryModel} is not synchronized.
* @author Grigor Iliev
*/
public class DefaultNavigationHistoryModel implements NavigationHistoryModel
{
private final LinkedList
histList = new LinkedList
();
private ListIterator
listIt = histList.listIterator();
private final Vector listeners = new Vector();
/**
* Creates a new instance of DefaultNavigationHistoryModel.
*/
public
DefaultNavigationHistoryModel() {
}
/**
* Registers the specified ActionListener to be
* notified about changes of the history list.
* @param l The ActionListener to register.
*/
public void
addActionListener(ActionListener l) { listeners.add(l); }
/**
* Removes the specified listener.
* @param l The ActionListener to remove.
*/
public void
removeActionListener(ActionListener l) { listeners.remove(l); }
/** Notifies registered listeners that the history list has changed. */
protected void
fireActionPerformed() {
ActionEvent e = new ActionEvent(this, ActionEvent.ACTION_PERFORMED, "");
for(ActionListener l : listeners) if(l != null) l.actionPerformed(e);
}
/**
* Adds the specified page to the history list after the current page.
* All pages after the the current page are removed from the history list and
* the added page becomes current. Note that this method does nothing if the
* current page is null or is equal to the page to be added.
* @param page The page to be added to the history list.
*/
public void
addPage(P page) {
if(page == null) return;
if(page.equals(getCurrentPage())) return;
while(listIt.hasNext()) {
listIt.next();
listIt.remove();
}
listIt.add(page);
fireActionPerformed();
}
/**
* Goes to the previous page in the history list.
* This means that the previous page becomes the current page of the history list.
* @return The new current page or null if
* there is no previous page in the history list.
* @see #hasBack
*/
public P
goBack() {
if(!hasBack()) return null;
listIt.previous();
fireActionPerformed();
return getCurrentPage();
}
/**
* Determines whether there is at least one
* page before the current page in the history list.
* @return true if there is at least one page before
* the current page in the history list, false otherwise.
*/
public boolean
hasBack() { return listIt.previousIndex() > 0; }
/**
* Goes to the next page in the history list.
* This means that the next page becomes the current page of the history list.
* @return The new current page or null if
* there is no next page in the history list.
* @see #hasForward
*/
public P
goForward() {
if(!listIt.hasNext()) return null;
listIt.next();
fireActionPerformed();
return getCurrentPage();
}
/**
* Determines whether there is at least one
* page after the current page in the history list.
* @return true if there is at least one page after
* the current page in the history list, false otherwise.
*/
public boolean
hasForward() { return listIt.hasNext(); }
/**
* Goes to the first page in the history list.
* This means that the first page becomes the current page of the history list.
*/
public void
goFirst() {
// We don't want to notify about changes if the history list is not modified.
if(listIt.previousIndex() < 1) return;
while(listIt.previousIndex() > 0) listIt.previous();
fireActionPerformed();
}
/**
* Goes to the last page in the history list.
* This means that the last page becomes the current page of the history list.
*/
public void
goLast() {
// We don't want to notify about changes if the history list is not modified.
if(!listIt.hasNext()) return;
while(listIt.hasNext()) listIt.next();
fireActionPerformed();
}
/**
* Gets the current page in the history list.
* @return The current page in the history list or
* null if the history list is empty.
*/
public P
getCurrentPage() {
int idx = listIt.previousIndex();
return (idx == -1) ? null : histList.get(idx);
}
/**
* Gets the current number of pages in the history list.
* @return The current number of pages in the history list.
*/
public int
getPageCount() { return histList.size(); }
/** Removes all pages from history list except the current page. */
public void
clearHistory() {
P p = getCurrentPage();
if(p == null) return;
histList.clear();
listIt = histList.listIterator();
listIt.add(p);
fireActionPerformed();
}
/**
* Removes from the model the last page that was returned by
* goBack or goForward.
* @see java.util.ListIterator#remove
*/
protected void
removePage() { listIt.remove(); }
}