asquare.gwt.tkdemo.client.TabHistoryCoordinator.java Source code

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Here is the source code for asquare.gwt.tkdemo.client.TabHistoryCoordinator.java

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/*
 * Copyright 2006 Mat Gessel <mat.gessel@gmail.com>
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package asquare.gwt.tkdemo.client;

import com.google.gwt.user.client.History;
import com.google.gwt.user.client.HistoryListener;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.SourcesTabEvents;
import com.google.gwt.user.client.ui.TabBar;
import com.google.gwt.user.client.ui.TabListener;

/**
 * Encapsulates the control logic which ensures that TabPanel state and History
 * state are consistent. The TabPanel will be updated when the History stack
 * changes and vice-versa.
 */
public class TabHistoryCoordinator implements HistoryListener, TabListener {
    private final HistoryWidgetCollection m_tabs;
    private final TabBar m_tabPanel;
    private final String m_windowTitle = Window.getTitle();

    private int m_selectedTab = -1;

    public TabHistoryCoordinator(HistoryWidgetCollection tabs, TabBar tabPanel, String initialTabToken) {
        m_tabs = tabs;
        m_tabPanel = tabPanel;

        int tabIndex = m_tabs.getIndexForToken(initialTabToken);
        selectTab(tabIndex);

        tabPanel.addTabListener(this);
        History.addHistoryListener(this);
    }

    public void selectTab(int tabIndex) {
        if (tabIndex < 0) {
            tabIndex = 0;
        }
        if (tabIndex != m_selectedTab) {
            m_selectedTab = tabIndex; // set first to prevent re-entry
            m_tabPanel.selectTab(tabIndex);
            Window.setTitle(m_windowTitle + " > " + m_tabs.getDescription(tabIndex));
        }
    }

    // HistoryListener methods
    public void onHistoryChanged(String historyToken) {
        int tabIndex = m_tabs.getIndexForToken(historyToken);
        selectTab(tabIndex);
    }

    // TabListener methods
    public boolean onBeforeTabSelected(SourcesTabEvents sender, int tabIndex) {
        return true;
    }

    public void onTabSelected(SourcesTabEvents sender, int tabIndex) {
        if (tabIndex != m_selectedTab) {
            History.newItem(m_tabs.getToken(tabIndex));
        }
    }
}