/jboss-as-7.1.1.Final/weld/src/main/java/org/jboss/as/weld/webtier/jsf/WeldApplication.java

  1/*
  2 * JBoss, Home of Professional Open Source
  3 * Copyright 2008, Red Hat Middleware LLC, and individual contributors
  4 * by the @authors tag. See the copyright.txt in the distribution for a
  5 * full listing of individual contributors.
  6 *
  7 * Licensed under the Apache License, Version 2.0 (the "License");
  8 * you may not use this file except in compliance with the License.
  9 * You may obtain a copy of the License at
 10 * http://www.apache.org/licenses/LICENSE-2.0
 11 * Unless required by applicable law or agreed to in writing, software
 12 * distributed under the License is distributed on an "AS IS" BASIS,
 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 14 * See the License for the specific language governing permissions and
 15 * limitations under the License.
 16 */
 17package org.jboss.as.weld.webtier.jsf;
 18
 19import org.jboss.weld.el.WeldELContextListener;
 20
 21import javax.el.ELResolver;
 22import javax.el.ExpressionFactory;
 23import javax.enterprise.inject.spi.BeanManager;
 24import javax.faces.application.Application;
 25import javax.naming.InitialContext;
 26import javax.naming.NamingException;
 27
 28/**
 29 * @author pmuir
 30 */
 31public class WeldApplication extends ForwardingApplication {
 32
 33    private static class AdjustableELResolver extends ForwardingELResolver {
 34
 35        private ELResolver delegate;
 36
 37        public void setDelegate(ELResolver delegate) {
 38            this.delegate = delegate;
 39        }
 40
 41        @Override
 42        protected ELResolver delegate() {
 43            return delegate;
 44        }
 45    }
 46
 47    private final Application application;
 48    private final AdjustableELResolver elResolver;
 49
 50    private volatile ExpressionFactory expressionFactory;
 51    private volatile boolean initialized = false;
 52    private volatile BeanManager beanManager;
 53
 54    public WeldApplication(Application application) {
 55        this.application = application;
 56        application.addELContextListener(new WeldELContextListener());
 57        elResolver = new AdjustableELResolver();
 58        elResolver.setDelegate(new DummyELResolver());
 59        application.addELResolver(elResolver);
 60    }
 61
 62    private void init() {
 63        if (!initialized &&  beanManager() != null) {
 64            synchronized (this) {
 65                if(!initialized &&  beanManager() != null) {
 66                    elResolver.setDelegate(beanManager().getELResolver());
 67                    initialized = true;
 68                }
 69            }
 70        }
 71    }
 72
 73    @Override
 74    protected Application delegate() {
 75        init();
 76        return application;
 77    }
 78
 79    @Override
 80    public ExpressionFactory getExpressionFactory() {
 81        init();
 82        // may be improved for thread safety, but right now the only risk is to invoke wrapExpressionFactory
 83        // multiple times for concurrent threads. This is ok, as the call is
 84        if (expressionFactory == null) {
 85            synchronized (this) {
 86                if (expressionFactory == null) {
 87                    BeanManager bm = beanManager();
 88                    if (bm == null) {
 89                        expressionFactory = application.getExpressionFactory();
 90                    } else {
 91                        expressionFactory = bm.wrapExpressionFactory(application.getExpressionFactory());
 92                    }
 93                }
 94            }
 95        }
 96        return expressionFactory;
 97    }
 98
 99    private BeanManager beanManager() {
100        if (beanManager == null) {
101            synchronized (this) {
102                if (beanManager == null) {
103                    try {
104                        beanManager = (BeanManager) new InitialContext().lookup("java:comp/BeanManager");
105                    } catch (NamingException e) {
106                        return null;
107                    }
108                }
109            }
110        }
111        return beanManager;
112    }
113
114}