org.colombbus.tangara.commons.resinject.MessageSenderAction.java Source code

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Here is the source code for org.colombbus.tangara.commons.resinject.MessageSenderAction.java

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/**
 * Tangara is an educational platform to get started with programming. Copyright
 * (C) 2010 Colombbus (http://www.colombbus.org)
 * 
 * This program is free software: you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 * 
 * This program 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 General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */
package org.colombbus.tangara.commons.resinject;

import java.awt.event.ActionEvent;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import javax.swing.AbstractAction;

import org.apache.commons.lang3.Validate;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Action which send a message (ie no argument method) to a target object when
 * its <code>actionPerformed</code> method is called.
 * <p>
 * Usage:
 * 
 * <pre>
 * Object target = ... // object receiving the message
 * String method = "doAction"; // method of target to call.
 *                             //This method has no arguments
 * 
 * MessageSenderAction msAction = new MessageSenderAction();
 * msAction.setTarget( target );
 * msAction.setMessage(method);
 * ...
 * 
 * msAction.actionPerformed(...); // call target.doAction
 * </pre>
 * 
 * </p>
 * 
 * @author gwen
 */
@SuppressWarnings({ "nls", "serial" })
public class MessageSenderAction extends AbstractAction {

    private static final Logger LOG = LoggerFactory.getLogger(MessageSenderAction.class);

    private Object target;
    private String methodName;
    private Method method;

    public MessageSenderAction() {
    }

    /**
     * Set the the target of the message
     * 
     * @param target
     *            the target of the message
     */
    public void setTarget(Object target) {
        Validate.notNull(target, "target argument is null");
        this.target = target;
    }

    /**
     * Set the message to send to the target when the action is performed
     * 
     * @param methodName
     *            a no argument method name of the target object
     */
    public void setMessage(String methodName) {
        Validate.notEmpty(methodName, "message argument is not a method call");
        this.methodName = methodName;
    }

    private void initializeMethodIfNecessary() {
        if (method != null)
            return;

        try {
            this.method = target.getClass().getMethod(methodName);
        } catch (NoSuchMethodException ex) {
            String errMsg = String.format("Target does not contains a method '%s'", methodName);
            LOG.warn(errMsg);
            throw new UnsupportedOperationException(errMsg);
        }
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        Validate.notNull(target, "target not initialized");
        Validate.notNull(methodName, "methodName not initialized");

        initializeMethodIfNecessary();

        try {
            method.invoke(target);
        } catch (IllegalAccessException accessEx) {
            String format = "Method '%s' not accessible";
            String msg = String.format(format, methodName);
            LOG.warn(msg);
            throw new UnsupportedOperationException(msg, accessEx);
        } catch (InvocationTargetException invocEx) {
            String format = "Invocation of method '%s' throw an exception";
            String msg = String.format(format, methodName);
            LOG.warn(msg);
            throw new UnsupportedOperationException(msg, invocEx);
        }
    }

}