LinkRidget.java

/*******************************************************************************
 * Copyright (c) 2009 Florian Pirchner and others.
 * 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:
 * Florian Pirchner � initial API and implementation (based on other ridgets of 
 *                    compeople AG)
 * compeople AG     - adjustments for Riena v1.2
 *******************************************************************************/
package org.eclipse.riena.internal.ui.ridgets.swt;

import java.util.Arrays;
import java.util.Collections;

import org.eclipse.core.databinding.beans.BeansObservables;
import org.eclipse.core.databinding.observable.value.IObservableValue;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.widgets.Link;

import org.eclipse.riena.core.util.ListenerList;
import org.eclipse.riena.core.util.StringUtils;
import org.eclipse.riena.ui.ridgets.AbstractMarkerSupport;
import org.eclipse.riena.ui.ridgets.ILinkRidget;
import org.eclipse.riena.ui.ridgets.IRidget;
import org.eclipse.riena.ui.ridgets.listener.ISelectionListener;
import org.eclipse.riena.ui.ridgets.swt.AbstractValueRidget;
import org.eclipse.riena.ui.ridgets.swt.BasicMarkerSupport;

/**
 * Ridget for an SWT {@link Link} widget.
 * 
 * @since 1.2
 */
public class LinkRidget extends AbstractValueRidget implements ILinkRidget {

	/**
	 * This property is used by the databinding to sync ridget and model. It is
	 * always fired before its sibling {@link ILinkRidget#PROPERTY_TEXT} to
	 * ensure that the model is updated before any listeners try accessing it.
	 * <p>
	 * This property is not API. Do not use in client code.
	 */
	private static final String PROPERTY_TEXT_INTERNAL = "textInternal"; //$NON-NLS-1$

	private final LinkSelectionObserver selectionObserver;

	private String text;
	private boolean textAlreadyInitialized;

	public LinkRidget() {
		selectionObserver = new LinkSelectionObserver(this);
	}

	@Override
	protected void checkUIControl(final Object uiControl) {
		checkType(uiControl, Link.class);
	}

	@Override
	protected void bindUIControl() {
		final Link control = getUIControl();
		if (control != null) {
			control.addSelectionListener(selectionObserver);
			initText();
			updateUIText();
		}
	}

	@Override
	protected void unbindUIControl() {
		super.unbindUIControl();
		final Link control = getUIControl();
		if (control != null) {
			control.removeSelectionListener(selectionObserver);
		}
	}

	@Override
	protected AbstractMarkerSupport createMarkerSupport() {
		return new BasicMarkerSupport(this, propertyChangeSupport);
	}

	@Override
	protected IObservableValue getRidgetObservable() {
		return BeansObservables.observeValue(this, PROPERTY_TEXT_INTERNAL);
	}

	public void addSelectionListener(final ISelectionListener listener) {
		selectionObserver.addListener(listener);
	}

	@Override
	public Link getUIControl() {
		return (Link) super.getUIControl();
	}

	public String getText() {
		return text;
	}

	/**
	 * This method is not API. Do not use in client code.
	 * 
	 * @noreference This method is not intended to be referenced by clients.
	 */
	public final String getTextInternal() {
		return getText();
	}

	/**
	 * Always returns true because mandatory markers do not make sense for this
	 * ridget.
	 */
	@Override
	public boolean isDisableMandatoryMarker() {
		return true;
	}

	public void removeSelectionListener(final ISelectionListener listener) {
		selectionObserver.removeListener(listener);
	}

	public void setText(final String text) {
		final String oldText = this.text;
		this.text = text;
		updateUIText();
		firePropertyChange(PROPERTY_TEXT_INTERNAL, oldText, this.text);
		firePropertyChange(ILinkRidget.PROPERTY_TEXT, oldText, this.text);
	}

	public void setText(final String text, final String link) {
		String mergedText;
		if (StringUtils.isDeepEmpty(text) && StringUtils.isDeepEmpty(link)) {
			mergedText = ""; //$NON-NLS-1$
		} else if (StringUtils.isDeepEmpty(link)) {
			mergedText = String.format("<a>%s</a>", convertNullToEmpty(text)); //$NON-NLS-1$
		} else {
			mergedText = String.format("<a href=\"%s\">%s</a>", convertNullToEmpty(link), convertNullToEmpty(text)); //$NON-NLS-1$
		}
		setText(mergedText);
	}

	/**
	 * This method is not API. Do not use in client code.
	 * 
	 * @noreference This method is not intended to be referenced by clients.
	 */
	public final void setTextInternal(final String text) {
		setText(text);
	}

	// helping methods
	//////////////////

	private String convertNullToEmpty(final String value) {
		return StringUtils.isDeepEmpty(value) ? "" : value; //$NON-NLS-1$
	}

	private void updateUIText() {
		final Link control = getUIControl();
		if (control != null) {
			control.setText(convertNullToEmpty(text));
		}
	}

	/**
	 * If the text of the ridget has no value, initialize it with the text of
	 * the UI control.
	 */
	private void initText() {
		if (text == null && !textAlreadyInitialized) {
			final Link control = getUIControl();
			if (control != null && !control.isDisposed()) {
				text = control.getText();
				textAlreadyInitialized = true;
			}
		}
	}

	// helping classes
	//////////////////

	/**
	 * Forwards selection events from the Link widget to a collection of
	 * ISelectionListeners.
	 */
	private static final class LinkSelectionObserver extends AbstractObserver<ISelectionListener> {
		public LinkSelectionObserver(final IRidget source) {
			super(source);
		}

		@Override
		protected ListenerList<ISelectionListener> createList() {
			return new ListenerList<ISelectionListener>(ISelectionListener.class);
		}

		@Override
		protected void fireAction(final SelectionEvent evt) {
			final ListenerList<ISelectionListener> listeners = getListeners();
			if (listeners != null) {
				final org.eclipse.riena.ui.ridgets.listener.SelectionEvent event = new org.eclipse.riena.ui.ridgets.listener.SelectionEvent(
						getSource(), Collections.EMPTY_LIST, Arrays.asList(evt.text));
				for (final ISelectionListener listener : listeners.getListeners()) {
					listener.ridgetSelected(event);
				}
			}
		}
	}

}