/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*
* C E D A R
* S O L U T I O N S "Software done right."
* S O F T W A R E
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*
* Copyright (c) 2013 Kenneth J. Pronovici.
* All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the Apache License, Version 2.0.
* See LICENSE for more information about the licensing terms.
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*
* Author : Kenneth J. Pronovici <pronovic@ieee.org>
* Language : Java 6
* Project : Common Java Functionality
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
package com.cedarsolutions.client.gwt.module.view;
import com.cedarsolutions.client.gwt.custom.tab.TabLayoutPanel;
import com.cedarsolutions.client.gwt.event.UnifiedEvent;
import com.cedarsolutions.client.gwt.event.UnifiedEventType;
import com.cedarsolutions.client.gwt.event.ViewEventHandler;
import com.google.gwt.event.logical.shared.BeforeSelectionEvent;
import com.google.gwt.event.logical.shared.BeforeSelectionHandler;
import com.google.gwt.user.client.History;
/**
* Specialized page that is intended to be a tab.
* @author Kenneth J. Pronovici <pronovic@ieee.org>
*/
public abstract class ModuleTabView extends ModulePageView implements IModuleTabView {
/** Parent tab layout panel. */
private TabLayoutPanel parentPanel;
/** Index of this tab on the layout panel. */
private int tabIndex;
/** Whether the tab has been initialized. */
private boolean initialized;
/** Event handler for the initialization event (if any). */
private ViewEventHandler initializationEventHandler;
/** Event handler for the selected event (if any). */
private ViewEventHandler selectedEventHandler;
/** Save off the "before selection" handler, so we can manipulate it. */
private SelectionHandler beforeSelectionHandler;
/**
* Set the context that this tab exists in.
* @param parentPanel Parent tab layout panel
* @param tabIndex Index of this tab on the layout panel
*/
@Override
public void setContext(TabLayoutPanel parentPanel, int tabIndex) {
this.parentPanel = parentPanel;
this.tabIndex = tabIndex;
this.beforeSelectionHandler = new SelectionHandler(this);
this.parentPanel.addBeforeSelectionHandler(this.beforeSelectionHandler);
}
/** Disable the tab, so it no longer handles selection events. */
@Override
public void disableTab() {
this.beforeSelectionHandler.disable();
}
/** Enable the tab, so it begins to handle selection events. */
@Override
public void enableTab() {
this.beforeSelectionHandler.enable();
}
/** Get the parent TabLayoutPanel. */
@Override
public TabLayoutPanel getParentPanel() {
return this.parentPanel;
}
/** Get the history token for this tab, or null for no history. */
@Override
public String getHistoryToken() {
return null;
}
/** Get the tab index. */
@Override
public int getTabIndex() {
return this.tabIndex;
}
/** Whether the tab has been initialized yet. */
@Override
public boolean isInitialized() {
return this.initialized;
}
/** Mark that the tab has been initialized. */
@Override
public void markInitialized() {
this.initialized = true;
}
/** Get the initialization event handler. */
@Override
public ViewEventHandler getInitializationEventHandler() {
return this.initializationEventHandler;
}
/** Set the initialization event handler. */
@Override
public void setInitializationEventHandler(ViewEventHandler initializationEventHandler) {
this.initializationEventHandler = initializationEventHandler;
}
/** Get the selected event handler. */
@Override
public ViewEventHandler getSelectedEventHandler() {
return this.selectedEventHandler;
}
/** Set the selected event handler. */
@Override
public void setSelectedEventHandler(ViewEventHandler selectedEventHandler) {
this.selectedEventHandler = selectedEventHandler;
}
/** Select the tab, as if the normal BeforeSelectionHandler was invoked. */
@Override
public void selectTab() {
if (!this.isInitialized()) {
if (this.getInitializationEventHandler() != null) {
UnifiedEvent init = new UnifiedEvent(UnifiedEventType.INIT_EVENT);
this.getInitializationEventHandler().handleEvent(init);
}
this.markInitialized();
}
// The selected event handler is always called, even when initialize is also called.
// That way, the client doesn't need any special logic for the "selected first time" case.
if (this.getSelectedEventHandler() != null) {
UnifiedEvent selected = new UnifiedEvent(UnifiedEventType.SELECTED_EVENT);
this.getSelectedEventHandler().handleEvent(selected);
}
if (this.getHistoryToken() != null) {
History.newItem(this.getHistoryToken(), false);
}
}
/** Initialization handler. */
protected static class SelectionHandler implements BeforeSelectionHandler<Integer> {
private boolean enabled;
private IModuleTabView view;
public SelectionHandler(IModuleTabView view) {
this.enabled = true;
this.view = view;
}
public void enable() {
this.enabled = true;
}
public void disable() {
this.enabled = false;
}
@Override
public void onBeforeSelection(BeforeSelectionEvent<Integer> event) {
onBeforeSelection(event.getItem());
}
protected void onBeforeSelection(int tabIndex) {
if (this.enabled) {
if (tabIndex == this.view.getTabIndex()) {
this.view.selectTab();
}
}
}
protected boolean isEnabled() {
return this.enabled;
}
}
}