Listening for a Vetoable Property Change Event : JavaBeans « Development « Java Tutorial






// A vetoable property change event is fired when a constrained property is changed. 
// A listener can veto the change by throwing PropertyVetoException and preventing the change.

import java.beans.PropertyChangeEvent;
import java.beans.PropertyVetoException;
import java.beans.VetoableChangeListener;
import java.beans.VetoableChangeSupport;

public class Main {
  public static void main(String[] argv) throws Exception {
    MyBean bean = new MyBean();
    bean.addVetoableChangeListener(new MyVetoableChangeListener());
  }
}

class MyVetoableChangeListener implements VetoableChangeListener {
  public void vetoableChange(PropertyChangeEvent evt)
      throws PropertyVetoException {
    Object oldValue = evt.getOldValue();

    Object newValue = evt.getNewValue();

    boolean veto = false;
    if (veto) {
      throw new PropertyVetoException("the reason for the veto", evt);
    }
  }
}

class MyBean {
  VetoableChangeSupport vceListeners = new VetoableChangeSupport(this);

  int myProperty;

  public int getMyProperty() {
    return myProperty;
  }

  public void setMyProperty(int newValue) throws PropertyVetoException {
    try {
      vceListeners.fireVetoableChange("myProperty", new Integer(myProperty),
          new Integer(newValue));
      myProperty = newValue;
    } catch (PropertyVetoException e) {
      throw e;
    }
  }

  public synchronized void addVetoableChangeListener(
      VetoableChangeListener listener) {
    vceListeners.addVetoableChangeListener(listener);
  }

  public synchronized void removeVetoableChangeListener(
      VetoableChangeListener listener) {
    vceListeners.removeVetoableChangeListener(listener);
  }

}








6.56.JavaBeans
6.56.1.Listening for Changes to the Selected File in a JFileChooser Dialog
6.56.2.Get a list of selected files
6.56.3.Listening for Changes to the Current Directory in a JFileChooser Dialog
6.56.4.Displaying the Current Directory in the Title of a JFileChooser Dialog
6.56.5.Setting an Accessory Component in a JFileChooser Dialog
6.56.6.Convert a bean to XML persistence
6.56.7.Listen for bean's property change event
6.56.8.List property names of a Bean
6.56.9.Prevent bean's property being serialized to XML
6.56.10.Create an instance a Bean
6.56.11.Convert an XML persistence to bean
6.56.12.Determine bean's property type
6.56.13.Listen for a constrained property change
6.56.14.Bean has a single property called property.
6.56.15.Implementing a Bound Property
6.56.16.Implementing a Constrained Property: fires a PropertyChangeEvent whenever its value is about to be changed.
6.56.17.Instantiating a Bean
6.56.18.Listing the Property Names of a Bean
6.56.19.Getting and Setting a Property of a Bean
6.56.20.Get and set the value of a property in a bean using Expression and Statement
6.56.21.Get and set an Object type property
6.56.22.gets and sets a primitive type property
6.56.23.gets and sets an array type property
6.56.24.Serializing a Bean to XML: XMLEncoder only persists the value of public properties.
6.56.25.Deserializing a Bean from XML
6.56.26.Preventing a Bean Property from Being Serialized to XML
6.56.27.Serializing an Immutable Bean Property to XML
6.56.28.Listening for a Property Change Event: A property change event is fired when a bound property is changed.
6.56.29.Listening for a Vetoable Property Change Event
6.56.30.Read bean's property value
6.56.31.extends SimpleBeanInfo
6.56.32.Get and set properties on a bean
6.56.33.Process bean properties getter by applying the JavaBean naming conventions.
6.56.34.Is JavaBean Compliant Setter
6.56.35.Constructs a method name from element's bean name for a given prefix
6.56.36.Returns attribute's setter method. If the method not found then NoSuchMethodException will be thrown.