common/plugins/org.eclipse.jpt.common.ui/src/org/eclipse/jpt/common/ui/internal/utility/swt/DropDownListBoxSelectionBinding.java - dali/webtools.dali - Git at Google

 /*******************************************************************************
  * Copyright (c) 2009, 2010 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.common.ui.internal.utility.swt;

 import org.eclipse.jpt.common.ui.internal.listeners.SWTPropertyChangeListenerWrapper;
 import org.eclipse.jpt.common.utility.internal.StringTools;
 import org.eclipse.jpt.common.utility.internal.Tools;
 import org.eclipse.jpt.common.utility.model.event.PropertyChangeEvent;
 import org.eclipse.jpt.common.utility.model.listener.PropertyChangeListener;
 import org.eclipse.jpt.common.utility.model.value.ListValueModel;
 import org.eclipse.jpt.common.utility.model.value.PropertyValueModel;
 import org.eclipse.jpt.common.utility.model.value.WritablePropertyValueModel;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.events.SelectionListener;

 /**
  * This binding can be used to keep a drop-down list box's selection
  * synchronized with a model. The selection can be modified by either the
  * drop-down list box or the model, so changes must be coordinated.
  * <p>
  * <strong>NB:</strong> A selected item value of <code>null</code> can be used
  * to clear the drop-down list box's selection. If <code>null</code> is a
  * valid item in the model list, an invalid selected item can be used to clear
  * the selection.
  *
  * @see ListValueModel
  * @see WritablePropertyValueModel
  * @see DropDownListBox
  * @see SWTTools
  */
 @SuppressWarnings("nls")
 final class DropDownListBoxSelectionBinding<E>
 	implements ListWidgetModelBinding.SelectionBinding
 {
 	// ***** model
 	/**
 	 * The underlying list model.
 	 */
 	private final ListValueModel<E> listModel;

 	/**
 	 * A writable value model on the underlying model selection.
 	 */
 	private final WritablePropertyValueModel<E> selectedItemModel;

 	/**
 	 * A listener that allows us to synchronize the drop-down list box's
 	 * selection with the model selection.
 	 */
 	private final PropertyChangeListener selectedItemChangeListener;

 	// ***** UI
 	/**
 	 * The drop-down list box whose selection we keep synchronized
 	 * with the model selection.
 	 */
 	private final DropDownListBox dropdownListBox;

 	/**
 	 * A listener that allows us to synchronize our selected item holder
 	 * with the drop-down list box's selection.
 	 */
 	private final SelectionListener dropdownListBoxSelectionListener;


 	// ********** constructor **********

 	/**
 	 * Constructor - all parameters are required.
 	 */
 	DropDownListBoxSelectionBinding(
 			ListValueModel<E> listModel,
 			WritablePropertyValueModel<E> selectedItemModel,
 			DropDownListBox dropdownListBox
 	) {
 		super();
 		if ((listModel == null) || (selectedItemModel == null) || (dropdownListBox == null)) {
 			throw new NullPointerException();
 		}
 		this.listModel = listModel;
 		this.selectedItemModel = selectedItemModel;
 		this.dropdownListBox = dropdownListBox;

 		this.selectedItemChangeListener = this.buildSelectedItemChangeListener();
 		this.selectedItemModel.addPropertyChangeListener(PropertyValueModel.VALUE, this.selectedItemChangeListener);

 		this.dropdownListBoxSelectionListener = this.buildDropDownListBoxSelectionListener();
 		this.dropdownListBox.addSelectionListener(this.dropdownListBoxSelectionListener);
 	}


 	// ********** initialization **********

 	private PropertyChangeListener buildSelectedItemChangeListener() {
 		return new SWTPropertyChangeListenerWrapper(this.buildSelectedItemChangeListener_());
 	}

 	private PropertyChangeListener buildSelectedItemChangeListener_() {
 		return new PropertyChangeListener() {
 			public void propertyChanged(PropertyChangeEvent event) {
 				DropDownListBoxSelectionBinding.this.selectedItemChanged(event);
 			}
 			@Override
 			public String toString() {
 				return "selected item listener";
 			}
 		};
 	}

 	private SelectionListener buildDropDownListBoxSelectionListener() {
 		return new SelectionListener() {
 			public void widgetSelected(SelectionEvent event) {
 				DropDownListBoxSelectionBinding.this.dropDownListBoxSelectionChanged(event);
 			}
 			public void widgetDefaultSelected(SelectionEvent event) {
 				DropDownListBoxSelectionBinding.this.dropDownListBoxDoubleClicked(event);
 			}
 			@Override
 			public String toString() {
 				return "drop-down list box selection listener";
 			}
 		};
 	}


 	// ********** ListWidgetModelBinding.SelectionBinding implementation **********

 	/**
 	 * Modifying the drop-down lisb box's selected item programmatically does
 	 * not trigger a SelectionEvent.
 	 * <p>
 	 * Pre-condition: The drop-down list box is not disposed.
 	 */
 	public void synchronizeListWidgetSelection() {
 		int oldIndex = this.dropdownListBox.getSelectionIndex();
 		E value = this.selectedItemModel.getValue();
 		int newIndex = this.indexOf(value);
 		if ((oldIndex != -1) && (newIndex != -1) && (newIndex != oldIndex)) {
 			this.dropdownListBox.deselect(oldIndex);
 		}
 		if (newIndex == -1) {
 			this.dropdownListBox.deselectAll();
 		} else {
 			if (newIndex != oldIndex) {
 				this.dropdownListBox.select(newIndex);
 			}
 		}
 	}

 	public void dispose() {
 		this.dropdownListBox.removeSelectionListener(this.dropdownListBoxSelectionListener);
 		this.selectedItemModel.removePropertyChangeListener(PropertyValueModel.VALUE, this.selectedItemChangeListener);
 	}


 	// ********** selected item **********

 	void selectedItemChanged(PropertyChangeEvent event) {
 		if ( ! this.dropdownListBox.isDisposed()) {
 			this.selectedItemChanged_(event);
 		}
 	}

 	/**
 	 * Modifying the drop-down list box's selected item programmatically does
 	 * not trigger a SelectionEvent.
 	 */
 	private void selectedItemChanged_(@SuppressWarnings("unused") PropertyChangeEvent event) {
 		this.synchronizeListWidgetSelection();
 	}

 	private int indexOf(E item) {
 		int len = this.listModel.size();
 		for (int i = 0; i < len; i++) {
 			if (Tools.valuesAreEqual(this.listModel.get(i), item)) {
 				return i;
 			}
 		}
 		// if 'null' is not in the list, use it to clear the selection
 		if (item == null) {
 			return -1;
 		}
 		// We can get here via one of the following:
 		// 1. The selected item model is invalid and not in sync with the list
 		//    model. This is not good and we don't make this (programming
 		//    error) obvious (e.g. via an exception). :-(
 		// 2. If both the selected item model and the list model are dependent
 		//    on the same underlying model, the selected item model may receive
 		//    its event first, resulting in a missing item. This will resolve
 		//    itself once the list model receives its event and synchronizes
 		//    with the same underlying model. This situation is acceptable.
 		return -1;

 // This is what we used to do:
 //		throw new IllegalStateException("selected item not found: " + item);
 	}


 	// ********** combo-box events **********

 	void dropDownListBoxSelectionChanged(SelectionEvent event) {
 		if ( ! this.dropdownListBox.isDisposed()) {
 			this.dropDownListBoxSelectionChanged_(event);
 		}
 	}

 	void dropDownListBoxDoubleClicked(SelectionEvent event) {
 		if ( ! this.dropdownListBox.isDisposed()) {
 			this.dropDownListBoxSelectionChanged_(event);
 		}
 	}

 	private void dropDownListBoxSelectionChanged_(@SuppressWarnings("unused") SelectionEvent event) {
 		this.selectedItemModel.setValue(this.getDropDownListBoxSelectedItem());
 	}

 	private E getDropDownListBoxSelectedItem() {
 		int selectionIndex = this.dropdownListBox.getSelectionIndex();
 		return (selectionIndex == -1) ? null : this.listModel.get(selectionIndex);
 	}


 	// ********** standard methods **********

 	@Override
 	public String toString() {
 		return StringTools.buildToStringFor(this, this.selectedItemModel);
 	}


 	// ********** adapter interface **********

 	/**
 	 * Adapter used by the drop-down list box selection binding to query and manipulate
 	 * the drop-down list box.
 	 */
 	interface DropDownListBox {

 		/**
 		 * Return whether the combo-box is "disposed".
 		 */
 		boolean isDisposed();

 		/**
 		 * Add the specified selection listener to the combo-box.
 		 */
 		void addSelectionListener(SelectionListener listener);

 		/**
 		 * Remove the specified selection listener from the combo-box.
 		 */
 		void removeSelectionListener(SelectionListener listener);

 		/**
 		 * Return the index of the combo-box's selection.
 		 */
 		int getSelectionIndex();

 		/**
 		 * Select the item at the specified index in the combo-box.
 		 */
 		void select(int index);

 		/**
 		 * Deselect the item at the specified index in the combo-box.
 		 */
 		void deselect(int index);

 		/**
 		 * Clear the combo-box's selection.
 		 */
 		void deselectAll();

 	}

 }
	/*******************************************************************************
	* Copyright (c) 2009, 2010 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.common.ui.internal.utility.swt;

	import org.eclipse.jpt.common.ui.internal.listeners.SWTPropertyChangeListenerWrapper;
	import org.eclipse.jpt.common.utility.internal.StringTools;
	import org.eclipse.jpt.common.utility.internal.Tools;
	import org.eclipse.jpt.common.utility.model.event.PropertyChangeEvent;
	import org.eclipse.jpt.common.utility.model.listener.PropertyChangeListener;
	import org.eclipse.jpt.common.utility.model.value.ListValueModel;
	import org.eclipse.jpt.common.utility.model.value.PropertyValueModel;
	import org.eclipse.jpt.common.utility.model.value.WritablePropertyValueModel;
	import org.eclipse.swt.events.SelectionEvent;
	import org.eclipse.swt.events.SelectionListener;

	/**
	* This binding can be used to keep a drop-down list box's selection
	* synchronized with a model. The selection can be modified by either the
	* drop-down list box or the model, so changes must be coordinated.
	* <p>
	* <strong>NB:</strong> A selected item value of <code>null</code> can be used
	* to clear the drop-down list box's selection. If <code>null</code> is a
	* valid item in the model list, an invalid selected item can be used to clear
	* the selection.
	*
	* @see ListValueModel
	* @see WritablePropertyValueModel
	* @see DropDownListBox
	* @see SWTTools
	*/
	@SuppressWarnings("nls")
	final class DropDownListBoxSelectionBinding<E>
	implements ListWidgetModelBinding.SelectionBinding
	{
	// ***** model
	/**
	* The underlying list model.
	*/
	private final ListValueModel<E> listModel;

	/**
	* A writable value model on the underlying model selection.
	*/
	private final WritablePropertyValueModel<E> selectedItemModel;

	/**
	* A listener that allows us to synchronize the drop-down list box's
	* selection with the model selection.
	*/
	private final PropertyChangeListener selectedItemChangeListener;

	// ***** UI
	/**
	* The drop-down list box whose selection we keep synchronized
	* with the model selection.
	*/
	private final DropDownListBox dropdownListBox;

	/**
	* A listener that allows us to synchronize our selected item holder
	* with the drop-down list box's selection.
	*/
	private final SelectionListener dropdownListBoxSelectionListener;


	// ******** constructor ********

	/**
	* Constructor - all parameters are required.
	*/
	DropDownListBoxSelectionBinding(
	ListValueModel<E> listModel,
	WritablePropertyValueModel<E> selectedItemModel,
	DropDownListBox dropdownListBox
	) {
	super();
	if ((listModel == null) \|\| (selectedItemModel == null) \|\| (dropdownListBox == null)) {
	throw new NullPointerException();
	}
	this.listModel = listModel;
	this.selectedItemModel = selectedItemModel;
	this.dropdownListBox = dropdownListBox;

	this.selectedItemChangeListener = this.buildSelectedItemChangeListener();
	this.selectedItemModel.addPropertyChangeListener(PropertyValueModel.VALUE, this.selectedItemChangeListener);

	this.dropdownListBoxSelectionListener = this.buildDropDownListBoxSelectionListener();
	this.dropdownListBox.addSelectionListener(this.dropdownListBoxSelectionListener);
	}


	// ******** initialization ********

	private PropertyChangeListener buildSelectedItemChangeListener() {
	return new SWTPropertyChangeListenerWrapper(this.buildSelectedItemChangeListener_());
	}

	private PropertyChangeListener buildSelectedItemChangeListener_() {
	return new PropertyChangeListener() {
	public void propertyChanged(PropertyChangeEvent event) {
	DropDownListBoxSelectionBinding.this.selectedItemChanged(event);
	}
	@Override
	public String toString() {
	return "selected item listener";
	}
	};
	}

	private SelectionListener buildDropDownListBoxSelectionListener() {
	return new SelectionListener() {
	public void widgetSelected(SelectionEvent event) {
	DropDownListBoxSelectionBinding.this.dropDownListBoxSelectionChanged(event);
	}
	public void widgetDefaultSelected(SelectionEvent event) {
	DropDownListBoxSelectionBinding.this.dropDownListBoxDoubleClicked(event);
	}
	@Override
	public String toString() {
	return "drop-down list box selection listener";
	}
	};
	}


	// ******** ListWidgetModelBinding.SelectionBinding implementation ********

	/**
	* Modifying the drop-down lisb box's selected item programmatically does
	* not trigger a SelectionEvent.
	* <p>
	* Pre-condition: The drop-down list box is not disposed.
	*/
	public void synchronizeListWidgetSelection() {
	int oldIndex = this.dropdownListBox.getSelectionIndex();
	E value = this.selectedItemModel.getValue();
	int newIndex = this.indexOf(value);
	if ((oldIndex != -1) && (newIndex != -1) && (newIndex != oldIndex)) {
	this.dropdownListBox.deselect(oldIndex);
	}
	if (newIndex == -1) {
	this.dropdownListBox.deselectAll();
	} else {
	if (newIndex != oldIndex) {
	this.dropdownListBox.select(newIndex);
	}
	}
	}

	public void dispose() {
	this.dropdownListBox.removeSelectionListener(this.dropdownListBoxSelectionListener);
	this.selectedItemModel.removePropertyChangeListener(PropertyValueModel.VALUE, this.selectedItemChangeListener);
	}


	// ******** selected item ********

	void selectedItemChanged(PropertyChangeEvent event) {
	if ( ! this.dropdownListBox.isDisposed()) {
	this.selectedItemChanged_(event);
	}
	}

	/**
	* Modifying the drop-down list box's selected item programmatically does
	* not trigger a SelectionEvent.
	*/
	private void selectedItemChanged_(@SuppressWarnings("unused") PropertyChangeEvent event) {
	this.synchronizeListWidgetSelection();
	}

	private int indexOf(E item) {
	int len = this.listModel.size();
	for (int i = 0; i < len; i++) {
	if (Tools.valuesAreEqual(this.listModel.get(i), item)) {
	return i;
	}
	}
	// if 'null' is not in the list, use it to clear the selection
	if (item == null) {
	return -1;
	}
	// We can get here via one of the following:
	// 1. The selected item model is invalid and not in sync with the list
	// model. This is not good and we don't make this (programming
	// error) obvious (e.g. via an exception). :-(
	// 2. If both the selected item model and the list model are dependent
	// on the same underlying model, the selected item model may receive
	// its event first, resulting in a missing item. This will resolve
	// itself once the list model receives its event and synchronizes
	// with the same underlying model. This situation is acceptable.
	return -1;

	// This is what we used to do:
	// throw new IllegalStateException("selected item not found: " + item);
	}


	// ******** combo-box events ********

	void dropDownListBoxSelectionChanged(SelectionEvent event) {
	if ( ! this.dropdownListBox.isDisposed()) {
	this.dropDownListBoxSelectionChanged_(event);
	}
	}

	void dropDownListBoxDoubleClicked(SelectionEvent event) {
	if ( ! this.dropdownListBox.isDisposed()) {
	this.dropDownListBoxSelectionChanged_(event);
	}
	}

	private void dropDownListBoxSelectionChanged_(@SuppressWarnings("unused") SelectionEvent event) {
	this.selectedItemModel.setValue(this.getDropDownListBoxSelectedItem());
	}

	private E getDropDownListBoxSelectedItem() {
	int selectionIndex = this.dropdownListBox.getSelectionIndex();
	return (selectionIndex == -1) ? null : this.listModel.get(selectionIndex);
	}


	// ******** standard methods ********

	@Override
	public String toString() {
	return StringTools.buildToStringFor(this, this.selectedItemModel);
	}


	// ******** adapter interface ********

	/**
	* Adapter used by the drop-down list box selection binding to query and manipulate
	* the drop-down list box.
	*/
	interface DropDownListBox {

	/**
	* Return whether the combo-box is "disposed".
	*/
	boolean isDisposed();

	/**
	* Add the specified selection listener to the combo-box.
	*/
	void addSelectionListener(SelectionListener listener);

	/**
	* Remove the specified selection listener from the combo-box.
	*/
	void removeSelectionListener(SelectionListener listener);

	/**
	* Return the index of the combo-box's selection.
	*/
	int getSelectionIndex();

	/**
	* Select the item at the specified index in the combo-box.
	*/
	void select(int index);

	/**
	* Deselect the item at the specified index in the combo-box.
	*/
	void deselect(int index);

	/**
	* Clear the combo-box's selection.
	*/
	void deselectAll();

	}

	}