com.googlecode.blaisemath.editor.MPropertyEditorSupport Maven / Gradle / Ivy
/**
* MPropertyEditorSupport.java
* Created on Jul 1, 2009
*/
package com.googlecode.blaisemath.editor;
/*
* #%L
* Firestarter
* --
* Copyright (C) 2009 - 2015 Elisha Peterson
* --
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* #L%
*/
import java.beans.PropertyEditorSupport;
/**
*
* MPropertyEditorSupport extends the basic property editor to
* improve handling of events. Maintains a temporary newValue object that
* tracks changes by the editor. These changes will pass events to any interested
* listeners if adjusted through the setNewValue method rather than directly.
* An interested bean can then check the "newValue" to see what has changed.
*
*
* The cancelEditAction() and stopEditAction() methods will
* either reset the editor to the initial state, or make a permanent change to the
* initial value. In both cases, an event may be fired to indicate that the external
* value has changed.
*
*
* Registered listeners hear when the new value is changed somehow. If interested
* in updating constantly, they should look to the getNewValue() method.
* If only interested in the final value, they should update only when the getValue()
* method returns a different value.
*
*
* External changes, e.g. to the underlying bean, should be handled by invoking the
* setValue method here. This calls the initEditorValue
* method to set up the editor based on some external value.
*
*
* @author Elisha Peterson
* @see java.beans.PropertyEditor
*/
public abstract class MPropertyEditorSupport extends PropertyEditorSupport {
/** Maintains the updated value of the object. */
protected Object newValue;
/** Flag to prevent extraneous events */
private boolean updating = false;
/**
* Contains revised/new value of the property. This may be called by
* external classes when they hear that the value has changed.
*
* @return initial value of the editor.
*/
public Object getNewValue() {
return newValue;
}
/**
* Internally adjusts the new value of the editor. This is intended to be
* called within event handling methods from customizer components.
*
* @param newValue the new value for the object.
*/
protected void setNewValue(Object newValue) {
this.newValue = newValue;
firePropertyChange();
}
/**
*
* Sets both the {@code newValue} property and the {@code value} property to the
* specified value.
*
*
* This is typically called when the editor is initially created and its value
* is changed to reflect an underlying bean property. It should not be called
* within any editor class itself. Instead, the editor class should update the
* {@code newValue} field with any changes made.
*
*
* @param value the value of the property being edited
*/
@Override
public void setValue(Object value) {
if (getNewValue() != value) {
setNewValue(value);
}
if (getValue() != value) {
super.setValue(value);
}
initEditorValue();
}
@Override
public void firePropertyChange() {
if (updating) {
return;
}
updating = true;
super.firePropertyChange();
updating = false;
}
/**
* This is called whenever an external class changes the value of this editor.
* It is intended to be overridden by subclasses and to propagate changes to
* any custom component.
*/
protected abstract void initEditorValue();
/**
* Called to indicate that the editor is finished editing.
*/
protected void cancelEditAction() {
if (newValue != getValue()) {
newValue = getValue();
initEditorValue();
firePropertyChange();
}
}
/**
* Called to indicate that the editor is finished editing.
*/
protected void stopEditAction() {
setValue(newValue);
}
}