com.ocpsoft.pretty.faces.el.resolver.SeamBeanNameResolver.java Source code

Introduction

Here is the source code for com.ocpsoft.pretty.faces.el.resolver.SeamBeanNameResolver.java

Source

/*
 * Copyright 2010 Lincoln Baxter, III
 * 
 * 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 com.ocpsoft.pretty.faces.el.resolver;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import javax.servlet.ServletContext;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.ocpsoft.pretty.faces.spi.ELBeanNameResolver;

/**
 * <p>
 * Implementation of {@link ELBeanNameResolver} that resolves Seam components.
 * </p>
 * 
 * <p>
 * This class uses reflection to call:
 * </p>
 * 
 * <pre>
 * Seam.getComponentName(beanClass)
 * </pre>
 * 
 * @author Christian Kaltepoth
 * 
 */
public class SeamBeanNameResolver implements ELBeanNameResolver {
    private final static Log log = LogFactory.getLog(SeamBeanNameResolver.class);

    /**
     * FQCN of the Seam class
     */
    private final static String SEAM_CLASS = "org.jboss.seam.Seam";

    /**
     * Name of the getComponentName method
     */
    private final static String GET_COMPONENT_NAME_METHOD = "getComponentName";

    /**
     * Reference to the getComponentNameMethod
     */
    private Method getComponentNameMethod = null;

    /*
     * Interface implementation
     */
    public boolean init(ServletContext servletContext, ClassLoader classLoader) {

        try {
            // get Seam class
            Class<?> seamClass = classLoader.loadClass(SEAM_CLASS);

            // get getComponentName method
            getComponentNameMethod = seamClass.getMethod(GET_COMPONENT_NAME_METHOD, Class.class);

            // initialization completed
            if (log.isDebugEnabled()) {
                log.debug("Seam environment detected. Enabling bean name resolving via Seam.");
            }
            return true;

        } catch (ClassNotFoundException e) {
            // Will happen in enviroments without Seam
            if (log.isDebugEnabled()) {
                log.debug("Seam class has not been found. Seam resolver will be disabled.");
            }
        } catch (NoSuchMethodException e) {
            // This method is expected on the Seam class
            log.warn("Cannot find method getComponentName() on Seam class.", e);
        } catch (SecurityException e) {
            log.warn("Unable to init resolver due to security restrictions", e);
        }

        // disable resolver
        return false;

    }

    /*
     * Interface implementation
     */
    public String getBeanName(Class<?> clazz) {

        // catch reflection exceptions
        try {

            // invoke getComponentName method
            String result = (String) getComponentNameMethod.invoke(null, clazz);

            // log name if call was successful
            if (log.isTraceEnabled() && result != null) {
                log.trace("Seam returned name '" + result + "' for class: " + clazz.getName());
            }

            // return result
            return result;

        } catch (IllegalAccessException e) {
            // security issues
            log.warn("Unable to call Seam.getComponentName() due to security restrictions", e);
        } catch (InvocationTargetException e) {
            // Seam's getComponentName() has thrown an exception
            log.error("Failed to invoke Seam.getComponentName()", e);
        }

        // we don't know the name
        return null;

    }

}