Tomcat example source code file (DefaultAnnotationProcessor.java)

This example Tomcat source code file (DefaultAnnotationProcessor.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

annotation, ejb, ejb, illegalaccessexception, illegalaccessexception, invocationtargetexception, method, method, naming, namingexception, object, object, persistencecontext, persistenceunit, reflection, resource, servlet, web, webserviceref, xml

The Tomcat DefaultAnnotationProcessor.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.catalina.util;

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

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.annotation.Resource;
import javax.ejb.EJB;
import javax.naming.NamingException;
import javax.persistence.PersistenceContext;
import javax.persistence.PersistenceUnit;
import javax.xml.ws.WebServiceRef;

import org.apache.AnnotationProcessor;


/**
 * Verify the annotation and Process it.
 *
 * @author Fabien Carrion
 * @author Remy Maucherat
 * @version $Revision: 467222 $, $Date: 2006-10-24 05:17:11 +0200 (mar., 24 oct. 2006) $
 */
public class DefaultAnnotationProcessor implements AnnotationProcessor {
    
    protected javax.naming.Context context = null;
    
    public DefaultAnnotationProcessor(javax.naming.Context context) {
        this.context = context;
    }


    /**
     * Call postConstruct method on the specified instance.
     */
    public void postConstruct(Object instance)
        throws IllegalAccessException, InvocationTargetException {
        
        Method[] methods = instance.getClass().getDeclaredMethods();
        Method postConstruct = null;
        for (int i = 0; i < methods.length; i++) {
            if (methods[i].isAnnotationPresent(PostConstruct.class)) {
                if ((postConstruct != null) 
                        || (methods[i].getParameterTypes().length != 0)
                        || (Modifier.isStatic(methods[i].getModifiers())) 
                        || (methods[i].getExceptionTypes().length > 0)
                        || (!methods[i].getReturnType().getName().equals("void"))) {
                    throw new IllegalArgumentException("Invalid PostConstruct annotation");
                }
                postConstruct = methods[i];
            }
        }

        // At the end the postconstruct annotated 
        // method is invoked
        if (postConstruct != null) {
            boolean accessibility = postConstruct.isAccessible();
            postConstruct.setAccessible(true);
            postConstruct.invoke(instance);
            postConstruct.setAccessible(accessibility);
        }
        
    }
    
    
    /**
     * Call preDestroy method on the specified instance.
     */
    public void preDestroy(Object instance)
        throws IllegalAccessException, InvocationTargetException {
        
        Method[] methods = instance.getClass().getDeclaredMethods();
        Method preDestroy = null;
        for (int i = 0; i < methods.length; i++) {
            if (methods[i].isAnnotationPresent(PreDestroy.class)) {
                if ((preDestroy != null) 
                        || (methods[i].getParameterTypes().length != 0)
                        || (Modifier.isStatic(methods[i].getModifiers())) 
                        || (methods[i].getExceptionTypes().length > 0)
                        || (!methods[i].getReturnType().getName().equals("void"))) {
                    throw new IllegalArgumentException("Invalid PreDestroy annotation");
                }
                preDestroy = methods[i];
            }
        }

        // At the end the postconstruct annotated 
        // method is invoked
        if (preDestroy != null) {
            boolean accessibility = preDestroy.isAccessible();
            preDestroy.setAccessible(true);
            preDestroy.invoke(instance);
            preDestroy.setAccessible(accessibility);
        }
        
    }
    
    
    /**
     * Inject resources in specified instance.
     */
    public void processAnnotations(Object instance)
        throws IllegalAccessException, InvocationTargetException, NamingException {
        
        if (context == null) {
            // No resource injection
            return;
        }
        
        // Initialize fields annotations
        Field[] fields = instance.getClass().getDeclaredFields();
        for (int i = 0; i < fields.length; i++) {
            if (fields[i].isAnnotationPresent(Resource.class)) {
                Resource annotation = (Resource) fields[i].getAnnotation(Resource.class);
                lookupFieldResource(context, instance, fields[i], annotation.name());
            }
            if (fields[i].isAnnotationPresent(EJB.class)) {
                EJB annotation = (EJB) fields[i].getAnnotation(EJB.class);
                lookupFieldResource(context, instance, fields[i], annotation.name());
            }
            if (fields[i].isAnnotationPresent(WebServiceRef.class)) {
                WebServiceRef annotation = 
                    (WebServiceRef) fields[i].getAnnotation(WebServiceRef.class);
                lookupFieldResource(context, instance, fields[i], annotation.name());
            }
            if (fields[i].isAnnotationPresent(PersistenceContext.class)) {
                PersistenceContext annotation = 
                    (PersistenceContext) fields[i].getAnnotation(PersistenceContext.class);
                lookupFieldResource(context, instance, fields[i], annotation.name());
            }
            if (fields[i].isAnnotationPresent(PersistenceUnit.class)) {
                PersistenceUnit annotation = 
                    (PersistenceUnit) fields[i].getAnnotation(PersistenceUnit.class);
                lookupFieldResource(context, instance, fields[i], annotation.name());
            }
        }
        
        // Initialize methods annotations
        Method[] methods = instance.getClass().getDeclaredMethods();
        for (int i = 0; i < methods.length; i++) {
            if (methods[i].isAnnotationPresent(Resource.class)) {
                Resource annotation = (Resource) methods[i].getAnnotation(Resource.class);
                lookupMethodResource(context, instance, methods[i], annotation.name());
            }
            if (methods[i].isAnnotationPresent(EJB.class)) {
                EJB annotation = (EJB) methods[i].getAnnotation(EJB.class);
                lookupMethodResource(context, instance, methods[i], annotation.name());
            }
            if (methods[i].isAnnotationPresent(WebServiceRef.class)) {
                WebServiceRef annotation = 
                    (WebServiceRef) methods[i].getAnnotation(WebServiceRef.class);
                lookupMethodResource(context, instance, methods[i], annotation.name());
            }
            if (methods[i].isAnnotationPresent(PersistenceContext.class)) {
                PersistenceContext annotation = 
                    (PersistenceContext) methods[i].getAnnotation(PersistenceContext.class);
                lookupMethodResource(context, instance, methods[i], annotation.name());
            }
            if (methods[i].isAnnotationPresent(PersistenceUnit.class)) {
                PersistenceUnit annotation = 
                    (PersistenceUnit) methods[i].getAnnotation(PersistenceUnit.class);
                lookupMethodResource(context, instance, methods[i], annotation.name());
            }
        }

    }
    
    
    /**
     * Inject resources in specified field.
     */
    protected static void lookupFieldResource(javax.naming.Context context, 
            Object instance, Field field, String name)
        throws NamingException, IllegalAccessException {
    
        Object lookedupResource = null;
        boolean accessibility = false;
        
        if ((name != null) &&
                (name.length() > 0)) {
            lookedupResource = context.lookup(name);
        } else {
            lookedupResource = context.lookup(instance.getClass().getName() + "/" + field.getName());
        }
        
        accessibility = field.isAccessible();
        field.setAccessible(true);
        field.set(instance, lookedupResource);
        field.setAccessible(accessibility);
    }


    /**
     * Inject resources in specified method.
     */
    protected static void lookupMethodResource(javax.naming.Context context, 
            Object instance, Method method, String name)
        throws NamingException, IllegalAccessException, InvocationTargetException {
        
        if (!method.getName().startsWith("set") 
                || method.getParameterTypes().length != 1
                || !method.getReturnType().getName().equals("void")) {
            throw new IllegalArgumentException("Invalid method resource injection annotation");
        }
        
        Object lookedupResource = null;
        boolean accessibility = false;
        
        if ((name != null) &&
                (name.length() > 0)) {
            lookedupResource = context.lookup(name);
        } else {
            lookedupResource = 
                context.lookup(instance.getClass().getName() + "/" + method.getName().substring(3));
        }
        
        accessibility = method.isAccessible();
        method.setAccessible(true);
        method.invoke(instance, lookedupResource);
        method.setAccessible(accessibility);
    }
    

}