/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 *
 *    (C) 2002-2008, Open Source Geospatial Foundation (OSGeo)
 *
 *    This library is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License as published by the Free Software Foundation;
 *    version 2.1 of the License.
 *
 *    This library 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
 *    Lesser General Public License for more details.
 */

package org.geotools.swt.control;

import org.eclipse.swt.events.ModifyEvent;
import org.eclipse.swt.events.ModifyListener;
import org.eclipse.swt.widgets.Composite;

/**
 * A text field control to work with integer values. It can be constrained to positive values if
 * desired.
 * <p>
 * Example of use:
 * <pre><code>
 * int initialValue = ...
 * boolean allowNegatives = false;
 * JIntegerField control = new JIntegerField(initialValue, allowNegatives);
 * control.addValueChangedListener( new ValueChangedListener() {
 *     public void onValueChanged( ValueChangedEvent ev ) {
 *         System.out.println("The new value is " + ev.getValue());
 *     }
 * });
 * </code></pre>
 *
 * @author Michael Bedward
 * @author Andrea Antonello (www.hydrologis.com)
 *
 *
 * @source $URL: http://svn.osgeo.org/geotools/trunk/modules/unsupported/swt/src/main/java/org/geotools/swt/control/JIntegerField.java $
 */
public class JIntegerField extends JValueField implements ModifyListener {

    private boolean fireEvents;
    private final boolean allowNegative;

    /**
     * Creates a new text field that allows negative values and
     * has an initial value of 0.
     */
    public JIntegerField( Composite parent, int style ) {
        this(parent, style, 0, true);
    }
    /**
     * Creates a new text field with an initial value of 0.
     *
     * @param allowNegative true if this field should allow negative values to
     *        be entered; false if only positive values are allowed
     */
    public JIntegerField( Composite parent, int style, boolean allowsNegative ) {
        this(parent, style, 0, allowsNegative);
    }

    /**
     * Creates a new text field that allows negative values and
     * the given initial value.
     *
     * @param value the initial value to display
     */
    public JIntegerField( Composite parent, int style, int value ) {
        this(parent, style, value, true);
    }

    /**
     * Creates a new text field with the given initial value.
     *
     * @param value the initial value to display
     * @param allowNegative true if this field should allow negative values to
     *        be entered; false if only positive values are allowed
     */
    public JIntegerField( Composite parent, int style, int value, boolean allowNegative ) {
        super(parent, style);

        addModifyListener(this);

        this.allowNegative = allowNegative;
        setValue(value);

    }

    /**
     * Get the current value of this control.
     *
     * @return the current value
     */
    public int getValue() {
        return Integer.parseInt(getText());
    }

    /**
     * Set the integer value of this control. A {@code ValueChangedEvent} will be
     * published to all {@code ValueChangedListeners}.
     * 
     * @param value the value to set
     *
     * @throws IllegalArgumentException if {@code value} is negative but the field
     *         only allows positive values
     */
    public void setValue( int value ) {
        setValue(value, true);
    }

    /**
     * Set the integer value of this control, optionally skipping notification of
     * the change to listeners.
     * <p>
     * This version is useful when two or more controls are synchronized (ie. changes
     * to the value of one control results in changes to the values of other controls).
     * In such a setting, firing change events can result in an endless cycle or a
     * mutex violation.
     *
     * @param value the value to set
     * @param publishEvent true to notify listeners of this change; false to skip
     *        notification
     *
     * @throws IllegalArgumentException if {@code value} is negative but the field
     *         only allows positive values
     */
    public void setValue( int value, boolean publishEvent ) {
        fireEvents = publishEvent;

        if (!allowNegative && value < 0) {
            throw new IllegalArgumentException(String.format(
                    "Negative value (%d) but text field set to only allow positive values", value));
        }
        setText(String.valueOf(value));
        fireEvents = true;
    }

    public void modifyText( ModifyEvent arg0 ) {
        if (fireEvents) {
            ValueChangedEvent<Integer> ev = new ValueChangedEvent<Integer>(JIntegerField.this, Integer.valueOf(getText()));
            fireValueChangedEvent(ev);
        }

    }

}