/*******************************************************************************
 * Copyright (c) 2007 Matthew Hall 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:
 *     Matthew Hall - initial API and implementation (bug 207844)
 *     IBM Corporation - initial API and implementation
 *     Brad Reynolds - initial API and implementation
 *     Matthew Hall - bug 212235
 *******************************************************************************/
module org.eclipse.jface.internal.databinding.swt.ShellObservableValue;

import java.lang.all;

import org.eclipse.core.databinding.observable.Diffs;
import org.eclipse.core.databinding.observable.Realm;
import org.eclipse.core.databinding.observable.value.IObservableValue;
import org.eclipse.jface.internal.databinding.provisional.swt.AbstractSWTObservableValue;
import org.eclipse.swt.widgets.Shell;

/**
 * An {@link IObservableValue} that tracks the text of a Shell.
 * 
 * @since 1.2
 */
public class ShellObservableValue : AbstractSWTObservableValue {

    private final Shell shell;

    /**
     * Constructs a ShellObservableValue which tracks the text of the given
     * Shell.
     * 
     * @param shell
     *            the shell to track
     */
    public this(Shell shell) {
        super(shell);
        this.shell = shell;
    }

    /**
     * Constructs a ShellObservableValue belonging to the given realm, which
     * tracks the text of the given shell.
     * 
     * @param realm
     *            the realm of the constructed observable
     * @param shell
     *            the shell to track
     */
    public this(Realm realm, Shell shell) {
        super(realm, shell);
        this.shell = shell;
    }

    protected void doSetValue(Object value) {
        String oldValue = shell.getText();
        String newValue = value is null ? "" : value.toString(); //$NON-NLS-1$
        shell.setText(newValue);

        if (!newValue.opEquals(oldValue)) {
            fireValueChange(Diffs.createValueDiff(oldValue, newValue));
        }
    }

    protected Object doGetValue() {
        return shell.getText();
    }

    public Object getValueType() {
        return String.classinfo;
    }
}