jpa/plugins/org.eclipse.jpt.ui/src/org/eclipse/jpt/ui/internal/mappings/db/DatabaseObjectCombo.java - dali/webtools.dali - Git at Google

 /*******************************************************************************
  * Copyright (c) 2008, 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.mappings.db;

 import java.util.Iterator;

 import org.eclipse.jpt.core.JpaDataSource;
 import org.eclipse.jpt.core.JpaNode;
 import org.eclipse.jpt.core.JpaProject;
 import org.eclipse.jpt.db.Catalog;
 import org.eclipse.jpt.db.Column;
 import org.eclipse.jpt.db.ConnectionListener;
 import org.eclipse.jpt.db.ConnectionProfile;
 import org.eclipse.jpt.db.Database;
 import org.eclipse.jpt.db.ForeignKey;
 import org.eclipse.jpt.db.Schema;
 import org.eclipse.jpt.db.Sequence;
 import org.eclipse.jpt.db.Table;
 import org.eclipse.jpt.ui.WidgetFactory;
 import org.eclipse.jpt.ui.internal.Tracing;
 import org.eclipse.jpt.ui.internal.listeners.SWTConnectionListenerWrapper;
 import org.eclipse.jpt.ui.internal.listeners.SWTPropertyChangeListenerWrapper;
 import org.eclipse.jpt.ui.internal.mappings.JptUiMappingsMessages;
 import org.eclipse.jpt.ui.internal.util.SWTUtil;
 import org.eclipse.jpt.ui.internal.widgets.Pane;
 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.osgi.util.NLS;
 import org.eclipse.swt.custom.CCombo;
 import org.eclipse.swt.events.ModifyEvent;
 import org.eclipse.swt.events.ModifyListener;
 import org.eclipse.swt.widgets.Composite;

 /**
  * This abstract pane keeps a combo in sync with the database objects
  * when a connection is active.
  *
  * @see CatalogCombo
  * @see ColumnCombo
  * @see SchemaCombo
  * @see SequenceCombo
  * @see TableCombo
  */
 @SuppressWarnings("nls")
 public abstract class DatabaseObjectCombo<T extends JpaNode>
 	extends Pane<T>
 {

 	/**
 	 * The main (only) widget of this pane.
 	 */
 	private CCombo comboBox;

 	/**
 	 * The listener added to the <code>ConnectionProfile</code>.
 	 * It keeps the combo in sync with the database metadata.
 	 */
 	private ConnectionListener connectionListener;

 	private PropertyChangeListener connectionProfileListener;

 	// ********** constructors **********

 	protected DatabaseObjectCombo(
 						Pane<? extends T> parentPane,
 						Composite parent
 	) {
 		super(parentPane, parent);
 	}

 	protected DatabaseObjectCombo(
 						Pane<?> parentPane,
 						PropertyValueModel<? extends T> subjectHolder,
 						Composite parent
 	) {
 		super(parentPane, subjectHolder, parent);
 	}

 	protected DatabaseObjectCombo(
 						PropertyValueModel<? extends T> subjectHolder,
 						Composite parent,
 						WidgetFactory widgetFactory
 	) {
 		super(subjectHolder, parent, widgetFactory);
 	}


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

 	@Override
 	protected void initialize() {
 		super.initialize();
 		this.connectionListener = this.buildConnectionListener();
 		this.connectionProfileListener = this.buildConnectionProfileListener();
 	}

 	protected ConnectionListener buildConnectionListener() {
 		return new SWTConnectionListenerWrapper(this.buildConnectionListener_());
 	}

 	protected ConnectionListener buildConnectionListener_() {
 		return new LocalConnectionListener();
 	}

 	protected PropertyChangeListener buildConnectionProfileListener() {
 		return new SWTPropertyChangeListenerWrapper(this.buildConnectionProfileListener_());
 	}

 	protected PropertyChangeListener buildConnectionProfileListener_() {
 		return new PropertyChangeListener(){

 			public void propertyChanged(PropertyChangeEvent event) {
 				connectionProfileChanged(event);
 			}
 		};
 	}

 	protected void connectionProfileChanged(PropertyChangeEvent event) {
 		if (event.getOldValue() != null) {
 			((ConnectionProfile) event.getOldValue()).removeConnectionListener(this.connectionListener);
 		}
 		if (event.getNewValue() != null) {
 			((ConnectionProfile) event.getNewValue()).addConnectionListener(this.connectionListener);
 		}
 		this.repopulateComboBox();
 	}

 	@Override
 	protected void initializeLayout(Composite container) {
 		this.comboBox = this.addEditableCCombo(container);
 		this.comboBox.addModifyListener(this.buildModifyListener());
 		SWTUtil.attachDefaultValueHandler(this.comboBox);
 	}

 	protected ModifyListener buildModifyListener() {
 		return new ModifyListener() {
 			public void modifyText(ModifyEvent e) {
 				DatabaseObjectCombo.this.comboBoxModified();
 			}
 		};
 	}


 	// ********** abstract methods **********

 	/**
 	 * Return the possible values to be added to the combo during
 	 * population.
 	 */
 	protected abstract Iterator<String> values();

 	/**
 	 * Return the default value, or <code>null</code> if no default is
 	 * specified. This method is only called when the subject is non-null.
 	 */
 	protected abstract String getDefaultValue();

 	/**
 	 * Return the current value from the subject.
 	 * This method is only called when the subject is non-null.
 	 */
 	protected abstract String getValue();

 	/**
 	 * Set the specified value as the new value on the subject.
 	 */
 	protected abstract void setValue(String value);


 	// ********** overrides **********

 	@Override
 	protected void engageListeners_(T subject) {
 		super.engageListeners_(subject);

 		subject.getJpaProject().getDataSource().addPropertyChangeListener(JpaDataSource.CONNECTION_PROFILE_PROPERTY, this.connectionProfileListener);
 		ConnectionProfile cp = subject.getJpaProject().getConnectionProfile();
 		if (cp != null) {
 			cp.addConnectionListener(this.connectionListener);
 		}
 	}

 	@Override
 	protected void disengageListeners_(T subject) {
 		ConnectionProfile cp = subject.getJpaProject().getConnectionProfile();
 		if (cp != null) {
 			cp.removeConnectionListener(this.connectionListener);
 		}
 		subject.getJpaProject().getDataSource().removePropertyChangeListener(JpaDataSource.CONNECTION_PROFILE_PROPERTY, this.connectionProfileListener);

 		super.disengageListeners_(subject);
 	}

 	@Override
 	public void enableWidgets(boolean enabled) {
 		super.enableWidgets(enabled);

 		if ( ! this.comboBox.isDisposed()) {
 			this.comboBox.setEnabled(enabled);
 		}
 	}

 	@Override
 	protected void propertyChanged(String propertyName) {
 		super.propertyChanged(propertyName);
 		this.updateSelectedItem();
 	}

 	@Override
 	protected void doPopulate() {
 		super.doPopulate();
 		this.populateComboBox();
 	}


 	// ********** populating **********

 	/**
 	 * Populate the combo-box list by clearing it, then adding first the default
 	 * value, if available, and then the possible choices.
 	 */
 	protected void populateComboBox() {
 		this.comboBox.removeAll();

 		this.comboBox.add(this.buildDefaultValueEntry());

 		if (this.connectionProfileIsActive()) {
 			for (Iterator<String> stream = this.values(); stream.hasNext(); ) {
 				this.comboBox.add(stream.next());
 			}
 		}

 		this.updateSelectedItem_();
 	}

 	protected String buildDefaultValueEntry() {
 		if (getSubject() == null) {
 			return JptUiMappingsMessages.NoneSelected;
 		}
 		String defaultValue = this.getDefaultValue();
 		return (defaultValue == null) ? this.buildNullDefaultValueEntry() : this.buildNonNullDefaultValueEntry(defaultValue);
 	}

 	protected String buildNullDefaultValueEntry() {
 		return JptUiMappingsMessages.DefaultEmpty;
 	}

 	protected String buildNonNullDefaultValueEntry(String defaultValue) {
 		return NLS.bind(
 						JptUiMappingsMessages.DefaultWithOneParam,
 						defaultValue
 					);
 	}

 	protected void updateSelectedItem() {
 		// make sure the default value is up to date (??? ~bjv)
 		String defaultValueEntry = this.buildDefaultValueEntry();
 		if ( ! this.comboBox.getItem(0).equals(defaultValueEntry)) {
 			this.comboBox.remove(0);
 			this.comboBox.add(defaultValueEntry, 0);
 		}

 		this.updateSelectedItem_();
 	}

 	/**
 	 * Updates the selected item by selecting the current value, if not
 	 * <code>null</code>, or select the default value if one is available,
 	 * otherwise remove the selection.
 	 */
 	protected void updateSelectedItem_() {
 		String value = (this.getSubject() == null) ? null : this.getValue();
 		if (value == null) {
 			// select the default value
 			this.comboBox.select(0);
 		} else {
 			// select the new value
 			if ( ! value.equals(this.comboBox.getText())) {
 				// This prevents the cursor from being set back to the beginning of the line (bug 234418).
 				// The reason we are hitting this method at all is because the
 				// context model is updating from the resource model in a way
 				// that causes change notifications to be fired (the annotation
 				// is added to the resource model, change notification occurs
 				// on the update thread, and then the name is set, these 2
 				// threads can get in the wrong order).
 				// The #valueChanged() method sets the populating flag to true,
 				// but in this case it is already set back to false when we
 				// receive notification back from the model because it has
 				// moved to the update thread and then jumps back on the UI thread.
 				this.comboBox.setText(value);
 			}
 		}
 	}


 	// ********** combo-box listener callback **********

 	protected void comboBoxModified() {
 		if ( ! this.isPopulating()) {
 			this.valueChanged(this.comboBox.getText());
 		}
 	}

 	/**
 	 * The combo-box selection has changed, update the model if necessary.
 	 * If the value has changed and the subject is null, we can build a subject
 	 * before setting the value.
 	 */
 	protected void valueChanged(String newValue) {
 		JpaNode subject = this.getSubject();
 		String oldValue;
 		if (subject == null) {
 			if (this.nullSubjectIsNotAllowed()) {
 				return;  // no subject to set the value on
 			}
 			oldValue = null;
 		} else {
 			oldValue = this.getValue();
 		}

 		// convert empty string or default to null
 		if (StringTools.stringIsEmpty(newValue) || this.valueIsDefault(newValue)) {
 			newValue = null;
 		}

 		// set the new value if it is different from the old value
 		if (this.valuesAreDifferent(oldValue, newValue)) {
 			this.setPopulating(true);

 			try {
 				this.setValue(newValue);
 			} finally {
 				this.setPopulating(false);
 			}
 		}
 	}

 	/**
 	 * Return whether we can set the value when the subject is null
 	 * (i.e. #setValue(String) will construct the subject if necessary).
 	 */
 	protected boolean nullSubjectIsAllowed() {
 		return false;
 	}

 	protected final boolean nullSubjectIsNotAllowed() {
 		return ! this.nullSubjectIsAllowed();
 	}

 	/**
 	 * pre-condition: value is not null
 	 */
 	protected boolean valueIsDefault(String value) {
 		return (this.comboBox.getItemCount() > 0)
 				&& value.equals(this.comboBox.getItem(0));
 	}

 	protected boolean valuesAreEqual(String value1, String value2) {
 		if ((value1 == null) && (value2 == null)) {
 			return true;	// both are null
 		}
 		if ((value1 == null) || (value2 == null)) {
 			return false;	// one is null but the other is not
 		}
 		return value1.equals(value2);
 	}

 	protected boolean valuesAreDifferent(String value1, String value2) {
 		return ! this.valuesAreEqual(value1, value2);
 	}


 	// ********** convenience methods **********

 	/**
 	 * Return the subject's JPA project.
 	 * Allow subclasses to override this method, so we can still get the JPA
 	 * project even when the subject is null.
 	 */
 	protected JpaProject getJpaProject() {
 		T subject = this.getSubject();
 		return (subject == null) ? null : subject.getJpaProject();
 	}

 	/**
 	 * Return the subject's connection profile.
 	 */
 	protected final ConnectionProfile getConnectionProfile() {
 		JpaProject jpaProject = this.getJpaProject();
 		return (jpaProject == null) ? null : jpaProject.getConnectionProfile();
 	}

 	/**
 	 * Return whether the subject's connection profile is active.
 	 */
 	protected final boolean connectionProfileIsActive() {
 		ConnectionProfile cp = this.getConnectionProfile();
 		return (cp != null) && cp.isActive();
 	}

 	/**
 	 * Returns the subject's database.
 	 */
 	protected final Database getDatabase() {
 		ConnectionProfile cp = this.getConnectionProfile();
 		return (cp == null) ? null : cp.getDatabase();
 	}


 	// ********** connection listener callbacks **********

 	protected void repopulateComboBox() {
 		if ( ! this.comboBox.isDisposed()) {
 			this.repopulate();
 		}
 	}

 	protected final void databaseChanged(Database database) {
 		if ( ! this.comboBox.isDisposed()) {
 			this.databaseChanged_(database);
 		}
 	}

 	protected void databaseChanged_(@SuppressWarnings("unused") Database database) {
 		// do nothing by default
 	}

 	protected final void catalogChanged(Catalog catalog) {
 		if ( ! this.comboBox.isDisposed()) {
 			this.catalogChanged_(catalog);
 		}
 	}

 	protected void catalogChanged_(@SuppressWarnings("unused") Catalog catalog) {
 		// do nothing by default
 	}

 	protected final void schemaChanged(Schema schema) {
 		if ( ! this.comboBox.isDisposed()) {
 			this.schemaChanged_(schema);
 		}
 	}

 	protected void schemaChanged_(@SuppressWarnings("unused") Schema schema) {
 		// do nothing by default
 	}

 	protected final void sequenceChanged(Sequence sequence) {
 		if ( ! this.comboBox.isDisposed()) {
 			this.sequenceChanged_(sequence);
 		}
 	}

 	protected void sequenceChanged_(@SuppressWarnings("unused") Sequence sequence) {
 		// do nothing by default
 	}

 	protected final void tableChanged(Table table) {
 		if ( ! this.comboBox.isDisposed()) {
 			this.tableChanged_(table);
 		}
 	}

 	protected void tableChanged_(@SuppressWarnings("unused") Table table) {
 		// do nothing by default
 	}

 	protected final void columnChanged(Column column) {
 		if ( ! this.comboBox.isDisposed()) {
 			this.columnChanged_(column);
 		}
 	}

 	protected void columnChanged_(@SuppressWarnings("unused") Column column) {
 		// do nothing by default
 	}

 	protected final void foreignKeyChanged(ForeignKey foreignKey) {
 		if ( ! this.comboBox.isDisposed()) {
 			this.foreignKeyChanged_(foreignKey);
 		}
 	}

 	protected void foreignKeyChanged_(@SuppressWarnings("unused") ForeignKey foreignKey) {
 		// do nothing by default
 	}

 	@Override
 	protected void log(String flag, String message) {
 		if (flag.equals(Tracing.UI_DB) && Tracing.booleanDebugOption(Tracing.UI_DB)) {
 			this.log(message);
 		} else {
 			super.log(flag, message);
 		}
 	}


 	// ********** connection listener **********

 	protected class LocalConnectionListener implements ConnectionListener {

 		protected LocalConnectionListener() {
 			super();
 		}

 		public void opened(ConnectionProfile profile) {
 			this.log("opened: " + profile.getName());
 			DatabaseObjectCombo.this.repopulateComboBox();
 		}

 		public void modified(ConnectionProfile profile) {
 			this.log("modified: " + profile.getName());
 			DatabaseObjectCombo.this.repopulateComboBox();
 		}

 		public boolean okToClose(ConnectionProfile profile) {
 			this.log("OK to close: " + profile.getName());
 			return true;
 		}

 		public void aboutToClose(ConnectionProfile profile) {
 			this.log("about to close: " + profile.getName());
 		}

 		public void closed(ConnectionProfile profile) {
 			this.log("closed: " + profile.getName());
 			DatabaseObjectCombo.this.repopulateComboBox();
 		}

 		public void databaseChanged(ConnectionProfile profile, Database database) {
 			this.log("database changed: " + database.getName());
 			DatabaseObjectCombo.this.databaseChanged(database);
 		}

 		public void catalogChanged(ConnectionProfile profile, Catalog catalog) {
 			this.log("catalog changed: " + catalog.getName());
 			DatabaseObjectCombo.this.catalogChanged(catalog);
 		}

 		public void schemaChanged(ConnectionProfile profile, Schema schema) {
 			this.log("schema changed: " + schema.getName());
 			DatabaseObjectCombo.this.schemaChanged(schema);
 		}

 		public void sequenceChanged(ConnectionProfile profile, Sequence sequence) {
 			this.log("sequence changed: " + sequence.getName());
 			DatabaseObjectCombo.this.sequenceChanged(sequence);
 		}

 		public void tableChanged(ConnectionProfile profile, Table table) {
 			this.log("table changed: " + table.getName());
 			DatabaseObjectCombo.this.tableChanged(table);
 		}

 		public void columnChanged(ConnectionProfile profile, Column column) {
 			this.log("column changed: " + column.getName());
 			DatabaseObjectCombo.this.columnChanged(column);
 		}

 		public void foreignKeyChanged(ConnectionProfile profile, ForeignKey foreignKey) {
 			this.log("foreign key changed: " + foreignKey.getName());
 			DatabaseObjectCombo.this.foreignKeyChanged(foreignKey);
 		}

 		protected void log(String message) {
 			DatabaseObjectCombo.this.log(Tracing.UI_DB, message);
 		}

 	}

 }
	/*******************************************************************************
	* Copyright (c) 2008, 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.mappings.db;

	import java.util.Iterator;

	import org.eclipse.jpt.core.JpaDataSource;
	import org.eclipse.jpt.core.JpaNode;
	import org.eclipse.jpt.core.JpaProject;
	import org.eclipse.jpt.db.Catalog;
	import org.eclipse.jpt.db.Column;
	import org.eclipse.jpt.db.ConnectionListener;
	import org.eclipse.jpt.db.ConnectionProfile;
	import org.eclipse.jpt.db.Database;
	import org.eclipse.jpt.db.ForeignKey;
	import org.eclipse.jpt.db.Schema;
	import org.eclipse.jpt.db.Sequence;
	import org.eclipse.jpt.db.Table;
	import org.eclipse.jpt.ui.WidgetFactory;
	import org.eclipse.jpt.ui.internal.Tracing;
	import org.eclipse.jpt.ui.internal.listeners.SWTConnectionListenerWrapper;
	import org.eclipse.jpt.ui.internal.listeners.SWTPropertyChangeListenerWrapper;
	import org.eclipse.jpt.ui.internal.mappings.JptUiMappingsMessages;
	import org.eclipse.jpt.ui.internal.util.SWTUtil;
	import org.eclipse.jpt.ui.internal.widgets.Pane;
	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.osgi.util.NLS;
	import org.eclipse.swt.custom.CCombo;
	import org.eclipse.swt.events.ModifyEvent;
	import org.eclipse.swt.events.ModifyListener;
	import org.eclipse.swt.widgets.Composite;

	/**
	* This abstract pane keeps a combo in sync with the database objects
	* when a connection is active.
	*
	* @see CatalogCombo
	* @see ColumnCombo
	* @see SchemaCombo
	* @see SequenceCombo
	* @see TableCombo
	*/
	@SuppressWarnings("nls")
	public abstract class DatabaseObjectCombo<T extends JpaNode>
	extends Pane<T>
	{

	/**
	* The main (only) widget of this pane.
	*/
	private CCombo comboBox;

	/**
	* The listener added to the <code>ConnectionProfile</code>.
	* It keeps the combo in sync with the database metadata.
	*/
	private ConnectionListener connectionListener;

	private PropertyChangeListener connectionProfileListener;

	// ******** constructors ********

	protected DatabaseObjectCombo(
	Pane<? extends T> parentPane,
	Composite parent
	) {
	super(parentPane, parent);
	}

	protected DatabaseObjectCombo(
	Pane<?> parentPane,
	PropertyValueModel<? extends T> subjectHolder,
	Composite parent
	) {
	super(parentPane, subjectHolder, parent);
	}

	protected DatabaseObjectCombo(
	PropertyValueModel<? extends T> subjectHolder,
	Composite parent,
	WidgetFactory widgetFactory
	) {
	super(subjectHolder, parent, widgetFactory);
	}


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

	@Override
	protected void initialize() {
	super.initialize();
	this.connectionListener = this.buildConnectionListener();
	this.connectionProfileListener = this.buildConnectionProfileListener();
	}

	protected ConnectionListener buildConnectionListener() {
	return new SWTConnectionListenerWrapper(this.buildConnectionListener_());
	}

	protected ConnectionListener buildConnectionListener_() {
	return new LocalConnectionListener();
	}

	protected PropertyChangeListener buildConnectionProfileListener() {
	return new SWTPropertyChangeListenerWrapper(this.buildConnectionProfileListener_());
	}

	protected PropertyChangeListener buildConnectionProfileListener_() {
	return new PropertyChangeListener(){

	public void propertyChanged(PropertyChangeEvent event) {
	connectionProfileChanged(event);
	}
	};
	}

	protected void connectionProfileChanged(PropertyChangeEvent event) {
	if (event.getOldValue() != null) {
	((ConnectionProfile) event.getOldValue()).removeConnectionListener(this.connectionListener);
	}
	if (event.getNewValue() != null) {
	((ConnectionProfile) event.getNewValue()).addConnectionListener(this.connectionListener);
	}
	this.repopulateComboBox();
	}

	@Override
	protected void initializeLayout(Composite container) {
	this.comboBox = this.addEditableCCombo(container);
	this.comboBox.addModifyListener(this.buildModifyListener());
	SWTUtil.attachDefaultValueHandler(this.comboBox);
	}

	protected ModifyListener buildModifyListener() {
	return new ModifyListener() {
	public void modifyText(ModifyEvent e) {
	DatabaseObjectCombo.this.comboBoxModified();
	}
	};
	}


	// ******** abstract methods ********

	/**
	* Return the possible values to be added to the combo during
	* population.
	*/
	protected abstract Iterator<String> values();

	/**
	* Return the default value, or <code>null</code> if no default is
	* specified. This method is only called when the subject is non-null.
	*/
	protected abstract String getDefaultValue();

	/**
	* Return the current value from the subject.
	* This method is only called when the subject is non-null.
	*/
	protected abstract String getValue();

	/**
	* Set the specified value as the new value on the subject.
	*/
	protected abstract void setValue(String value);


	// ******** overrides ********

	@Override
	protected void engageListeners_(T subject) {
	super.engageListeners_(subject);

	subject.getJpaProject().getDataSource().addPropertyChangeListener(JpaDataSource.CONNECTION_PROFILE_PROPERTY, this.connectionProfileListener);
	ConnectionProfile cp = subject.getJpaProject().getConnectionProfile();
	if (cp != null) {
	cp.addConnectionListener(this.connectionListener);
	}
	}

	@Override
	protected void disengageListeners_(T subject) {
	ConnectionProfile cp = subject.getJpaProject().getConnectionProfile();
	if (cp != null) {
	cp.removeConnectionListener(this.connectionListener);
	}
	subject.getJpaProject().getDataSource().removePropertyChangeListener(JpaDataSource.CONNECTION_PROFILE_PROPERTY, this.connectionProfileListener);

	super.disengageListeners_(subject);
	}

	@Override
	public void enableWidgets(boolean enabled) {
	super.enableWidgets(enabled);

	if ( ! this.comboBox.isDisposed()) {
	this.comboBox.setEnabled(enabled);
	}
	}

	@Override
	protected void propertyChanged(String propertyName) {
	super.propertyChanged(propertyName);
	this.updateSelectedItem();
	}

	@Override
	protected void doPopulate() {
	super.doPopulate();
	this.populateComboBox();
	}


	// ******** populating ********

	/**
	* Populate the combo-box list by clearing it, then adding first the default
	* value, if available, and then the possible choices.
	*/
	protected void populateComboBox() {
	this.comboBox.removeAll();

	this.comboBox.add(this.buildDefaultValueEntry());

	if (this.connectionProfileIsActive()) {
	for (Iterator<String> stream = this.values(); stream.hasNext(); ) {
	this.comboBox.add(stream.next());
	}
	}

	this.updateSelectedItem_();
	}

	protected String buildDefaultValueEntry() {
	if (getSubject() == null) {
	return JptUiMappingsMessages.NoneSelected;
	}
	String defaultValue = this.getDefaultValue();
	return (defaultValue == null) ? this.buildNullDefaultValueEntry() : this.buildNonNullDefaultValueEntry(defaultValue);
	}

	protected String buildNullDefaultValueEntry() {
	return JptUiMappingsMessages.DefaultEmpty;
	}

	protected String buildNonNullDefaultValueEntry(String defaultValue) {
	return NLS.bind(
	JptUiMappingsMessages.DefaultWithOneParam,
	defaultValue
	);
	}

	protected void updateSelectedItem() {
	// make sure the default value is up to date (??? ~bjv)
	String defaultValueEntry = this.buildDefaultValueEntry();
	if ( ! this.comboBox.getItem(0).equals(defaultValueEntry)) {
	this.comboBox.remove(0);
	this.comboBox.add(defaultValueEntry, 0);
	}

	this.updateSelectedItem_();
	}

	/**
	* Updates the selected item by selecting the current value, if not
	* <code>null</code>, or select the default value if one is available,
	* otherwise remove the selection.
	*/
	protected void updateSelectedItem_() {
	String value = (this.getSubject() == null) ? null : this.getValue();
	if (value == null) {
	// select the default value
	this.comboBox.select(0);
	} else {
	// select the new value
	if ( ! value.equals(this.comboBox.getText())) {
	// This prevents the cursor from being set back to the beginning of the line (bug 234418).
	// The reason we are hitting this method at all is because the
	// context model is updating from the resource model in a way
	// that causes change notifications to be fired (the annotation
	// is added to the resource model, change notification occurs
	// on the update thread, and then the name is set, these 2
	// threads can get in the wrong order).
	// The #valueChanged() method sets the populating flag to true,
	// but in this case it is already set back to false when we
	// receive notification back from the model because it has
	// moved to the update thread and then jumps back on the UI thread.
	this.comboBox.setText(value);
	}
	}
	}


	// ******** combo-box listener callback ********

	protected void comboBoxModified() {
	if ( ! this.isPopulating()) {
	this.valueChanged(this.comboBox.getText());
	}
	}

	/**
	* The combo-box selection has changed, update the model if necessary.
	* If the value has changed and the subject is null, we can build a subject
	* before setting the value.
	*/
	protected void valueChanged(String newValue) {
	JpaNode subject = this.getSubject();
	String oldValue;
	if (subject == null) {
	if (this.nullSubjectIsNotAllowed()) {
	return; // no subject to set the value on
	}
	oldValue = null;
	} else {
	oldValue = this.getValue();
	}

	// convert empty string or default to null
	if (StringTools.stringIsEmpty(newValue) \|\| this.valueIsDefault(newValue)) {
	newValue = null;
	}

	// set the new value if it is different from the old value
	if (this.valuesAreDifferent(oldValue, newValue)) {
	this.setPopulating(true);

	try {
	this.setValue(newValue);
	} finally {
	this.setPopulating(false);
	}
	}
	}

	/**
	* Return whether we can set the value when the subject is null
	* (i.e. #setValue(String) will construct the subject if necessary).
	*/
	protected boolean nullSubjectIsAllowed() {
	return false;
	}

	protected final boolean nullSubjectIsNotAllowed() {
	return ! this.nullSubjectIsAllowed();
	}

	/**
	* pre-condition: value is not null
	*/
	protected boolean valueIsDefault(String value) {
	return (this.comboBox.getItemCount() > 0)
	&& value.equals(this.comboBox.getItem(0));
	}

	protected boolean valuesAreEqual(String value1, String value2) {
	if ((value1 == null) && (value2 == null)) {
	return true; // both are null
	}
	if ((value1 == null) \|\| (value2 == null)) {
	return false; // one is null but the other is not
	}
	return value1.equals(value2);
	}

	protected boolean valuesAreDifferent(String value1, String value2) {
	return ! this.valuesAreEqual(value1, value2);
	}


	// ******** convenience methods ********

	/**
	* Return the subject's JPA project.
	* Allow subclasses to override this method, so we can still get the JPA
	* project even when the subject is null.
	*/
	protected JpaProject getJpaProject() {
	T subject = this.getSubject();
	return (subject == null) ? null : subject.getJpaProject();
	}

	/**
	* Return the subject's connection profile.
	*/
	protected final ConnectionProfile getConnectionProfile() {
	JpaProject jpaProject = this.getJpaProject();
	return (jpaProject == null) ? null : jpaProject.getConnectionProfile();
	}

	/**
	* Return whether the subject's connection profile is active.
	*/
	protected final boolean connectionProfileIsActive() {
	ConnectionProfile cp = this.getConnectionProfile();
	return (cp != null) && cp.isActive();
	}

	/**
	* Returns the subject's database.
	*/
	protected final Database getDatabase() {
	ConnectionProfile cp = this.getConnectionProfile();
	return (cp == null) ? null : cp.getDatabase();
	}


	// ******** connection listener callbacks ********

	protected void repopulateComboBox() {
	if ( ! this.comboBox.isDisposed()) {
	this.repopulate();
	}
	}

	protected final void databaseChanged(Database database) {
	if ( ! this.comboBox.isDisposed()) {
	this.databaseChanged_(database);
	}
	}

	protected void databaseChanged_(@SuppressWarnings("unused") Database database) {
	// do nothing by default
	}

	protected final void catalogChanged(Catalog catalog) {
	if ( ! this.comboBox.isDisposed()) {
	this.catalogChanged_(catalog);
	}
	}

	protected void catalogChanged_(@SuppressWarnings("unused") Catalog catalog) {
	// do nothing by default
	}

	protected final void schemaChanged(Schema schema) {
	if ( ! this.comboBox.isDisposed()) {
	this.schemaChanged_(schema);
	}
	}

	protected void schemaChanged_(@SuppressWarnings("unused") Schema schema) {
	// do nothing by default
	}

	protected final void sequenceChanged(Sequence sequence) {
	if ( ! this.comboBox.isDisposed()) {
	this.sequenceChanged_(sequence);
	}
	}

	protected void sequenceChanged_(@SuppressWarnings("unused") Sequence sequence) {
	// do nothing by default
	}

	protected final void tableChanged(Table table) {
	if ( ! this.comboBox.isDisposed()) {
	this.tableChanged_(table);
	}
	}

	protected void tableChanged_(@SuppressWarnings("unused") Table table) {
	// do nothing by default
	}

	protected final void columnChanged(Column column) {
	if ( ! this.comboBox.isDisposed()) {
	this.columnChanged_(column);
	}
	}

	protected void columnChanged_(@SuppressWarnings("unused") Column column) {
	// do nothing by default
	}

	protected final void foreignKeyChanged(ForeignKey foreignKey) {
	if ( ! this.comboBox.isDisposed()) {
	this.foreignKeyChanged_(foreignKey);
	}
	}

	protected void foreignKeyChanged_(@SuppressWarnings("unused") ForeignKey foreignKey) {
	// do nothing by default
	}

	@Override
	protected void log(String flag, String message) {
	if (flag.equals(Tracing.UI_DB) && Tracing.booleanDebugOption(Tracing.UI_DB)) {
	this.log(message);
	} else {
	super.log(flag, message);
	}
	}


	// ******** connection listener ********

	protected class LocalConnectionListener implements ConnectionListener {

	protected LocalConnectionListener() {
	super();
	}

	public void opened(ConnectionProfile profile) {
	this.log("opened: " + profile.getName());
	DatabaseObjectCombo.this.repopulateComboBox();
	}

	public void modified(ConnectionProfile profile) {
	this.log("modified: " + profile.getName());
	DatabaseObjectCombo.this.repopulateComboBox();
	}

	public boolean okToClose(ConnectionProfile profile) {
	this.log("OK to close: " + profile.getName());
	return true;
	}

	public void aboutToClose(ConnectionProfile profile) {
	this.log("about to close: " + profile.getName());
	}

	public void closed(ConnectionProfile profile) {
	this.log("closed: " + profile.getName());
	DatabaseObjectCombo.this.repopulateComboBox();
	}

	public void databaseChanged(ConnectionProfile profile, Database database) {
	this.log("database changed: " + database.getName());
	DatabaseObjectCombo.this.databaseChanged(database);
	}

	public void catalogChanged(ConnectionProfile profile, Catalog catalog) {
	this.log("catalog changed: " + catalog.getName());
	DatabaseObjectCombo.this.catalogChanged(catalog);
	}

	public void schemaChanged(ConnectionProfile profile, Schema schema) {
	this.log("schema changed: " + schema.getName());
	DatabaseObjectCombo.this.schemaChanged(schema);
	}

	public void sequenceChanged(ConnectionProfile profile, Sequence sequence) {
	this.log("sequence changed: " + sequence.getName());
	DatabaseObjectCombo.this.sequenceChanged(sequence);
	}

	public void tableChanged(ConnectionProfile profile, Table table) {
	this.log("table changed: " + table.getName());
	DatabaseObjectCombo.this.tableChanged(table);
	}

	public void columnChanged(ConnectionProfile profile, Column column) {
	this.log("column changed: " + column.getName());
	DatabaseObjectCombo.this.columnChanged(column);
	}

	public void foreignKeyChanged(ConnectionProfile profile, ForeignKey foreignKey) {
	this.log("foreign key changed: " + foreignKey.getName());
	DatabaseObjectCombo.this.foreignKeyChanged(foreignKey);
	}

	protected void log(String message) {
	DatabaseObjectCombo.this.log(Tracing.UI_DB, message);
	}

	}

	}