/*******************************************************************************
 * Copyright (c) 2007 Brad Reynolds 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:
 *     Brad Reynolds - initial API and implementation
 ******************************************************************************/

module org.eclipse.jface.examples.databinding.snippets.Snippet011ValidateMultipleBindingsSnippet;

import java.lang.all;

import org.eclipse.core.databinding.DataBindingContext;
import org.eclipse.core.databinding.UpdateValueStrategy;
import org.eclipse.core.databinding.observable.Realm;
import org.eclipse.core.databinding.observable.value.IObservableValue;
import org.eclipse.core.databinding.observable.value.IValueChangeListener;
import org.eclipse.core.databinding.observable.value.ValueChangeEvent;
import org.eclipse.core.databinding.observable.value.WritableValue;
import org.eclipse.core.databinding.validation.IValidator;
import org.eclipse.core.databinding.validation.ValidationStatus;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.jface.databinding.swt.SWTObservables;
import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;

/**
 * Snippet that validates values across multiple bindings on change of each
 * observable. If the values of the target observables are not equal the model
 * is not updated. When the values are equal they will be written to sysout.
 * 
 * @author Brad Reynolds
 */
public class Snippet011ValidateMultipleBindingsSnippet {
    public static void main(String[] args) {
        Realm.runWithDefault(SWTObservables.getRealm(Display.getDefault()),
                new Runnable() {
                    public void run() {
                        Snippet011ValidateMultipleBindingsSnippet.run();
                    }
                });
    }

    private static void run() {
        Shell shell = new Shell();

        View view = new View(shell);
        final Model model = new Model();

        DataBindingContext dbc = new DataBindingContext();
        dbc.bindValue(SWTObservables.observeText(view.text1, SWT.Modify),
                model.value1, new UpdateValueStrategy()
                        .setAfterConvertValidator(new CrossFieldValidator(
                                model.value2)), null);
        dbc.bindValue(SWTObservables.observeText(view.text2, SWT.Modify),
                model.value2, new UpdateValueStrategy()
                        .setAfterConvertValidator(new CrossFieldValidator(
                                model.value1)), null);

        // DEBUG - print to show value change
        model.value1.addValueChangeListener(new IValueChangeListener() {
            public void handleValueChange(ValueChangeEvent event) {
                System.out.println("Value 1: " + model.value1.getValue());
            }
        });

        // DEBUG - print to show value change
        model.value2.addValueChangeListener(new IValueChangeListener() {
            public void handleValueChange(ValueChangeEvent event) {
                System.out.println("Value 2: " + model.value2.getValue());
            }
        });

        shell.pack();
        shell.open();
        Display display = shell.getDisplay();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch())
                display.sleep();
        }
        display.dispose();
    }

    /**
     * @since 3.2
     * 
     */
    private static final class CrossFieldValidator implements IValidator {
        /**
         * 
         */
        private final IObservableValue other;

        /**
         * @param model
         */
        private CrossFieldValidator(IObservableValue other) {
            this.other = other;
        }

        public IStatus validate(Object value) {
            if (!value.equals(other.getValue())) {
                return ValidationStatus.ok();
            }
            return ValidationStatus.error("values cannot be the same");
        }
    }

    static class Model {
        WritableValue value1 = new WritableValue();
        WritableValue value2 = new WritableValue();
    }

    static class View {
        Text text1;
        Text text2;

        View(Composite composite) {
            composite.setLayout(new GridLayout(2, true));
            text1 = new Text(composite, SWT.BORDER);
            text2 = new Text(composite, SWT.BORDER);
        }
    }
}
void main( String[] args ){
    Snippet011ValidateMultipleBindingsSnippet.main(args);
}