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/*******************************************************************************
* Copyright (c) 2009 Oracle. All rights reserved.
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0, which accompanies this distribution
* and is available at http://www.eclipse.org/legal/epl-v10.html.
*
* Contributors:
* Oracle - initial API and implementation
******************************************************************************/
package org.eclipse.jpt.ui.internal.utility.swt;
import java.util.HashSet;
import org.eclipse.jpt.ui.internal.listeners.SWTPropertyChangeListenerWrapper;
import org.eclipse.jpt.utility.internal.StringTools;
import org.eclipse.jpt.utility.model.event.PropertyChangeEvent;
import org.eclipse.jpt.utility.model.listener.PropertyChangeListener;
import org.eclipse.jpt.utility.model.value.PropertyValueModel;
import org.eclipse.swt.events.DisposeEvent;
import org.eclipse.swt.events.DisposeListener;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Widget;
/**
* This controller enables a model boolean to control either the 'enabled' or
* 'visible' properties of a set of SWT controls; i.e. the
* controls' properties are kept in synch with the model boolean,
* but not vice-versa.
*
* @see PropertyValueModel
* @see Control#setEnabled(boolean)
* @see Control#setVisible(boolean)
*/
final class BooleanStateController {
/** A value model on the underlying model boolean. */
private final PropertyValueModel<Boolean> booleanHolder;
/**
* A listener that allows us to synchronize the control states with
* changes in the value of the model boolean.
*/
private final PropertyChangeListener booleanChangeListener;
/**
* The set of controls whose state is kept in sync with the model boolean.
*/
private final HashSet<Control> controls = new HashSet<Control>();
/**
* A listener that allows us to stop listening to stuff when all the
* controls are disposed. (Critical for preventing memory leaks.)
*/
private final DisposeListener controlDisposeListener;
/**
* The default setting for the state; for when the underlying model is
* <code>null</code>. The default [default value] is <code>false<code>.
*/
private final boolean defaultValue;
/**
* The adapter determines whether the 'enabled' or 'visible' property is
* controlled.
*/
private final Adapter adapter;
// ********** constructor **********
/**
* Constructor - the boolean holder, the controls, and the adapter are required.
*/
BooleanStateController(
PropertyValueModel<Boolean> booleanHolder,
Iterable<? extends Control> controls,
boolean defaultValue,
Adapter adapter
) {
super();
if ((booleanHolder == null) || (controls == null) || (adapter == null)) {
throw new NullPointerException();
}
this.booleanHolder = booleanHolder;
this.defaultValue = defaultValue;
this.adapter = adapter;
this.booleanChangeListener = this.buildBooleanChangeListener();
this.booleanHolder.addPropertyChangeListener(PropertyValueModel.VALUE, this.booleanChangeListener);
this.controlDisposeListener = this.buildControlDisposeListener();
this.addControls(controls);
}
// ********** initialization **********
private PropertyChangeListener buildBooleanChangeListener() {
return new SWTPropertyChangeListenerWrapper(this.buildBooleanChangeListener_());
}
private PropertyChangeListener buildBooleanChangeListener_() {
return new PropertyChangeListener() {
public void propertyChanged(PropertyChangeEvent event) {
BooleanStateController.this.booleanChanged(event);
}
@Override
public String toString() {
return "boolean listener"; //$NON-NLS-1$
}
};
}
private DisposeListener buildControlDisposeListener() {
return new DisposeListener() {
public void widgetDisposed(DisposeEvent event) {
BooleanStateController.this.controlDisposed(event);
}
@Override
public String toString() {
return "control dispose listener"; //$NON-NLS-1$
}
};
}
// ********** behavior **********
private void addControls(Iterable<? extends Control> controls_) {
boolean b = this.getBooleanValue();
for (Control control : controls_) {
this.addControl(control, b);
}
}
private void addControl(Control control, boolean b) {
if (this.controls.add(control)) {
control.addDisposeListener(this.controlDisposeListener);
this.setControlState(control, b);
}
}
/**
* The model has changed - synchronize the controls.
* If the new model value is null, use the controller's default value
* (which is typically false).
*/
void booleanChanged(PropertyChangeEvent event) {
this.setControlStates((Boolean) event.getNewValue());
}
private void setControlStates(Boolean b) {
this.setControlStates(this.booleanValue(b));
}
private void setControlStates(boolean b) {
for (Control control : this.controls) {
this.setControlState(control, b);
}
}
private boolean getBooleanValue() {
return this.booleanValue(this.booleanHolder.getValue());
}
private boolean booleanValue(Boolean b) {
return (b != null) ? b.booleanValue() : this.getDefaultValue();
}
private void setControlState(Control control, boolean b) {
if ( ! control.isDisposed()) {
this.adapter.setState(control, b);
}
}
private boolean getDefaultValue() {
return this.defaultValue;
}
// ********** dispose **********
void controlDisposed(DisposeEvent event) {
// the control is not yet "disposed" when we receive this event
// so we can still remove our listener
Widget control = event.widget;
control.removeDisposeListener(this.controlDisposeListener);
this.controls.remove(control);
if (this.controls.isEmpty()) {
this.booleanHolder.removePropertyChangeListener(PropertyValueModel.VALUE, this.booleanChangeListener);
}
}
// ********** standard methods **********
@Override
public String toString() {
return StringTools.buildToStringFor(this, this.booleanHolder);
}
// ********** adapters **********
interface Adapter {
void setState(Control control, boolean b);
}
}
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