de.bstreit.java.springaop.observablebean.PropertyChangeSupportWithInterface.java Source code

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Here is the source code for de.bstreit.java.springaop.observablebean.PropertyChangeSupportWithInterface.java

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/*
 * Copyright 2014 Bernhard Streit (Bernhard.Streit+springaop@gmail.com)
 * 
 * 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.
 */
package de.bstreit.java.springaop.observablebean;

import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;

import org.aspectj.lang.ProceedingJoinPoint;
import org.springframework.beans.BeanWrapper;
import org.springframework.beans.BeanWrapperImpl;

/**
 * Internal helper class, one instance per proxied object, manages listener
 * registration and fires the change event.
 * 
 * @author Bernhard Streit (Bernhard.Streit+github@gmail.com)
 */
class PropertyChangeSupportWithInterface implements IObservableBean {

    private PropertyChangeSupport pcs;
    private BeanWrapper beanWrapper;

    PropertyChangeSupportWithInterface(Object observedObject) {
        pcs = new PropertyChangeSupport(observedObject);
        beanWrapper = new BeanWrapperImpl(observedObject);
    }

    public void addPropertyChangeListener(PropertyChangeListener listener) {
        pcs.addPropertyChangeListener(listener);
    }

    public void removePropertyChangeListener(PropertyChangeListener listener) {
        pcs.removePropertyChangeListener(listener);
    }

    public PropertyChangeListener[] getPropertyChangeListeners() {
        return pcs.getPropertyChangeListeners();
    }

    public void addPropertyChangeListener(String propertyName, PropertyChangeListener listener) {
        pcs.addPropertyChangeListener(propertyName, listener);
    }

    public void removePropertyChangeListener(String propertyName, PropertyChangeListener listener) {
        pcs.removePropertyChangeListener(propertyName, listener);
    }

    public PropertyChangeListener[] getPropertyChangeListeners(String propertyName) {
        return pcs.getPropertyChangeListeners(propertyName);
    }

    public boolean hasListeners(String propertyName) {
        return pcs.hasListeners(propertyName);
    }

    /**
     * Retrieve old and new value, invoke setter and finally fire property change
     * event.
     * 
     * @param pjp
     * @throws Throwable
     */
    void handleSetterInvocation(ProceedingJoinPoint pjp) throws Throwable {
        // the method name is "setPropertyName", hence stripping of the "set"
        // from the beginning gives us "PropertyName"
        final String propertyName = pjp.getSignature().getName().substring(3);

        final Object oldValue = beanWrapper.getPropertyValue(propertyName);
        final Object newValue = pjp.getArgs()[0];

        // perform the setting
        pjp.proceed();

        // fire property change, if no exception occurred
        pcs.firePropertyChange(propertyName, oldValue, newValue);
    }
}