com.netxforge.screens.editing.base.util.DateChooserComboObservableValue.java Source code

Introduction

Here is the source code for com.netxforge.screens.editing.base.util.DateChooserComboObservableValue.java

Source

/*******************************************************************************
 * Copyright (c) Oct 9, 2012 NetXForge.
 * 
 * This program is free software: you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details. You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>
 * 
 * Contributors: Christophe Bouhier - initial API and implementation and/or
 * initial documentation
 *******************************************************************************/
package com.netxforge.screens.editing.base.util;

import java.util.Date;

import org.eclipse.core.databinding.observable.Diffs;
import org.eclipse.core.databinding.observable.Realm;
import org.eclipse.core.databinding.observable.value.AbstractObservableValue;
import org.eclipse.jface.databinding.swt.SWTObservables;
import org.eclipse.nebula.widgets.datechooser.DateChooserCombo;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.DisposeEvent;
import org.eclipse.swt.events.DisposeListener;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;

/**
 * 
 * @author Christophe Bouhier
 *
 */
public class DateChooserComboObservableValue extends AbstractObservableValue {
    /**
     * {@link DateChooserCombo} widget that this is being observed.
     */
    protected final DateChooserCombo combo;

    /**
     * SWT event that on firing this observable will fire change events to its
     * listeners.
     */
    private final int updateEventType;

    /**
     * Flag to track when the model is updating the widget. When
     * <code>true</code> the handlers for the SWT events should not process
     * the event as this would cause an infinite loop.
     */
    private boolean updating = false;

    /**
     * Previous value of the Date.
     */
    private Date oldValue;

    private Listener updateListener = new Listener() {
        public void handleEvent(Event event) {
            if (!updating) {
                Date newValue = combo.getValue();

                if ((newValue == null && oldValue != null) || (newValue != null && !newValue.equals(oldValue))) {
                    fireValueChange(Diffs.createValueDiff(oldValue, newValue));
                    oldValue = newValue;
                }
            }
        }
    };

    /**
     * Valid types for the {@link #updateEventType}.
     */
    private static final int[] validUpdateEventTypes = new int[] { SWT.Modify, SWT.FocusOut, SWT.None };

    private DisposeListener disposeListener = new DisposeListener() {
        public void widgetDisposed(DisposeEvent e) {
            DateChooserComboObservableValue.this.dispose();
        }
    };

    public DateChooserComboObservableValue(final DateChooserCombo combo, int updateEventType) {
        this(SWTObservables.getRealm(combo.getDisplay()), combo, updateEventType);
    }

    public DateChooserComboObservableValue(final Realm realm, final DateChooserCombo combo, int updateEventType) {
        super(realm);

        boolean eventValid = false;
        for (int i = 0; !eventValid && i < validUpdateEventTypes.length; i++) {
            eventValid = (updateEventType == validUpdateEventTypes[i]);
        }
        if (!eventValid) {
            throw new IllegalArgumentException("UpdateEventType [" + updateEventType + "] is not supported."); //$NON-NLS-1$//$NON-NLS-2$
        }

        this.combo = combo;
        this.updateEventType = updateEventType;
        if (updateEventType != SWT.None) {
            combo.addListener(updateEventType, updateListener);
        }

        combo.addDisposeListener(disposeListener);
    }

    public DateChooserCombo getDateChooserCombo() {
        return combo;
    }

    public void dispose() {
        if (!combo.isDisposed()) {
            if (updateEventType != SWT.None) {
                combo.removeListener(updateEventType, updateListener);
            }
        }
        super.dispose();
    }

    protected Object doGetValue() {
        return oldValue = combo.getValue();
    }

    /**
     * Sets the bound {@link DateChooserCombo} combo to the passed <code>value</code>.
     * 
     * @param value new value, Date expected
     * @see org.eclipse.core.databinding.observable.value.AbstractObservableValue#doSetValue(java.lang.Object)
     * @throws ClassCastException if the value is anything other than a Date
     */
    protected void doSetValue(final Object value) {
        try {
            updating = true;
            combo.setValue((Date) value);
            oldValue = combo.getValue();
        } finally {
            updating = false;
        }
    }

    public Object getValueType() {
        return Date.class;
    }
}