CComboRidget.java

/*******************************************************************************
 * Copyright (c) 2007, 2014 compeople AG 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:
 *    compeople AG - initial API and implementation
 *******************************************************************************/
package org.eclipse.riena.internal.ui.ridgets.swt;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

import org.eclipse.core.databinding.BindingException;
import org.eclipse.core.databinding.UpdateValueStrategy;
import org.eclipse.core.databinding.conversion.Converter;
import org.eclipse.core.databinding.observable.list.IObservableList;
import org.eclipse.core.databinding.observable.value.IObservableValue;
import org.eclipse.jface.databinding.swt.ISWTObservableValue;
import org.eclipse.jface.databinding.swt.SWTObservables;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.CCombo;
import org.eclipse.swt.events.ModifyEvent;
import org.eclipse.swt.events.ModifyListener;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.graphics.Color;

import org.eclipse.riena.ui.ridgets.ICComboRidget;
import org.eclipse.riena.ui.ridgets.IRidget;
import org.eclipse.riena.ui.ridgets.swt.AbstractComboRidget;

/**
 * Ridget for {@link CCombo} widgets.
 */
public class CComboRidget extends AbstractComboRidget implements ICComboRidget {

	private static final String ORIGINAL_BACKGROUND_KEY = "CCR.orBaKe"; //$NON-NLS-1$

	private final ModifyListener modifyListener;

	public CComboRidget() {
		modifyListener = new CComboModifyListener();
		addPropertyChangeListener(IRidget.PROPERTY_ENABLED, new PropertyChangeListener() {
			public void propertyChange(final PropertyChangeEvent evt) {
				if (getUIControl() != null) {
					final boolean isEnabled = ((Boolean) evt.getNewValue()).booleanValue();
					updateBgColor(isEnabled);
				}
			}
		});

	}

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

	@Override
	protected void addSelectionListener(final org.eclipse.swt.events.SelectionListener listener) {
		getUIControl().addSelectionListener(listener);
	}

	@Override
	protected void addTextModifyListener() {
		getUIControl().addModifyListener(modifyListener);
	}

	@Override
	protected void bindUIControl() {
		super.bindUIControl();
		if (getUIControl() != null) {
			updateBgColor(isEnabled());
		}
	}

	@Override
	protected void addConverter(final UpdateValueStrategy targetToModelStrategy, final IObservableValue selectionValue) {
		final Object selectionType = selectionValue.getValueType();
		targetToModelStrategy.setConverter(new Converter(Object.class, selectionType) {
			public Object convert(final Object fromObject) {
				if (fromObject == null) {
					return null;
				}
				if (fromObject.getClass() == getToType()) {
					return fromObject;
				}
				if (fromObject.toString().isEmpty()) {
					return null;
				}
				return fromObject;
			}
		});
	}

	@Override
	protected void checkUIControl(final Object uiControl) {
		checkType(uiControl, CCombo.class);
		if (uiControl != null) {
			final int style = ((CCombo) uiControl).getStyle();
			if ((style & SWT.READ_ONLY) == 0) {
				throw new BindingException("Combo must be READ_ONLY"); //$NON-NLS-1$
			}
		}
	}

	@Override
	protected void clearUIControlListSelection() {
		getUIControl().deselectAll();
		// Workaround for an SWT feature: when the user clicks in the list,
		// an asynchronous selection event is added to the end of the event 
		// queue, which will silenty an item. We asynchronously clear the list 
		// as well
		getUIControl().getDisplay().asyncExec(new Runnable() {
			public void run() {
				final CCombo combo = getUIControl();
				if (combo != null && !combo.isDisposed()) {
					combo.clearSelection(); // this does not change the text
				}
			}
		});
	}

	@Override
	protected String[] getUIControlItems() {
		return getUIControl().getItems();
	}

	@Override
	protected IObservableList getUIControlItemsObservable() {
		return SWTObservables.observeItems(getUIControl());
	}

	@Override
	protected ISWTObservableValue getUIControlSelectionObservable() {
		return SWTObservables.observeSelection(getUIControl());
	}

	@Override
	protected String getUIControlText() {
		return getUIControl().getText();
	}

	@Override
	protected int indexOfInUIControl(final String item) {
		return getUIControl().indexOf(item);
	}

	@Override
	protected void removeAllFromUIControl() {
		getUIControl().removeAll();
	}

	@Override
	protected void removeSelectionListener(final SelectionListener listener) {
		getUIControl().removeSelectionListener(listener);
	}

	@Override
	protected void removeTextModifyListener() {
		getUIControl().removeModifyListener(modifyListener);
	}

	@Override
	protected void selectInUIControl(final int index) {
		getUIControl().select(index);
	}

	@Override
	protected void setItemsToControl(final String[] arrItems) {
		getUIControl().setItems(arrItems);
	}

	@Override
	protected void setItemsToControl(final Object[] arrItems) {
		setItemsToControl(getStringArray(arrItems));
	}

	@Override
	protected void setTextToControl(final String text) {
		getUIControl().setText(text);
	}

	@Override
	protected void updateEditable() {
		// unused
	}

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

	/**
	 * This was introduced as to address Bug 323449.
	 * <p>
	 * The Text/CCombo widgets will not change their background to gray when disabled, once a non-null background color has been used in the enabled state.
	 */
	private void updateBgColor(final boolean isEnabled) {
		// pre-condition: control is known to be != null
		final CCombo control = getUIControl();
		if (isEnabled) {
			if (control.getData(ORIGINAL_BACKGROUND_KEY) != null) {
				control.setBackground((Color) control.getData(ORIGINAL_BACKGROUND_KEY));
				control.setData(ORIGINAL_BACKGROUND_KEY, null);
			}
		} else {
			if (control.getData(ORIGINAL_BACKGROUND_KEY) == null) {
				control.setData(ORIGINAL_BACKGROUND_KEY, control.getBackground());
			}
			final Color disabledBg = control.getDisplay().getSystemColor(SWT.COLOR_WIDGET_BACKGROUND);
			// note: the DisabledPainter will paint the DISABLED_MARKER_BACKGROUND over this, so we are good
			control.setBackground(disabledBg);
		}
		updateMarkers();
	}

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

	/**
	 * Keeps the ridget's text value in-sync with the widget's text value
	 */
	private final class CComboModifyListener implements ModifyListener {
		public void modifyText(final ModifyEvent e) {
			if (!isOutputOnly()) {
				setText(getUIControlText());
			}
		}
	}
}