org.wicketstuff.javaee.JavaEEBeanLocator Maven / Gradle / Ivy

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/*
 * 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.wicketstuff.javaee;

import javax.naming.InitialContext;
import javax.naming.NamingException;

import org.apache.wicket.proxy.IProxyTargetLocator;
import org.apache.wicket.util.lang.Objects;
import org.wicketstuff.javaee.naming.IJndiNamingStrategy;

/**
 * Implementation of {@link IProxyTargetLocator} to locate ejbs using Java EE 5
 * resource injection. To use this technique in a Wicket Page, annotate a
 * instance variable with
 *
 * @author Filippo Diotalevi
 * @EJB, e.g.

 * 
 * private
 * @EJB(name="ejb/myejb") org.acme.MyEjb myejb
 * 

 * If the 'name' attribute is specified, the
 * {@link JavaEEBeanLocator} will search in the JNDI
 * registry for an EJB named 'java:comp/env/<name>'
 * (in the example: 'java:comp/env/ejb/myejb')
 * 
 * If the 'name' attribute is not specified the
 * {@link JavaEEBeanLocator} will search in the JNDI
 * registry for an EJB named
 * 'java:comp/env/<complete-class-name-of-the-ejb>'
 * (in the example: 'java:comp/env/com.acme.MyEjb)
 */
public class JavaEEBeanLocator implements IProxyTargetLocator {

    private String beanName;
    private Class beanType;
    private IJndiNamingStrategy namingStrategy;

    /**
     * Constructor
     *
     * @param beanId   bean name
     * @param beanType bean class
     * @param namingStrategy - naming strategy
     */
    public JavaEEBeanLocator(String beanId, Class beanType, IJndiNamingStrategy namingStrategy) {
        if (beanType == null) {
            throw new IllegalArgumentException("[beanType] argument cannot be null");
        }
        this.beanType = beanType;
        this.beanName = beanId;
        this.namingStrategy = namingStrategy;
    }

    /**
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(Object obj) {
        if (obj instanceof JavaEEBeanLocator) {
            JavaEEBeanLocator other = (JavaEEBeanLocator) obj;
            return beanType.equals(other.beanType)
                    && Objects.equal(beanName, other.beanName);
        }
        return false;
    }

    public String getBeanName() {
        return beanName;
    }

    public Class getBeanType() {
        return beanType;
    }

    /**
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        int hashcode = beanType.hashCode();
        if (beanName != null) {
            hashcode = hashcode + (127 * beanName.hashCode());
        }
        return hashcode;
    }

    /**
     * @see org.apache.wicket.proxy.IProxyTargetLocator#locateProxyTarget()
     */
    @Override
	public Object locateProxyTarget() {
        if (beanName != null && beanName.length() > 0) {
            return lookupEjb(beanName, beanType);
        } else {
            return lookupEjb(null, beanType);
        }
    }

    private String calculateName(String name, Class type) {
        return namingStrategy.calculateName(name, type);
    }

    private Object lookupEjb(String name, Class type) {
        String lookupName = calculateName(name, type);
        InitialContext ic;
        try {
            ic = new InitialContext();
            return ic.lookup(lookupName);
        } catch (NamingException e) {
            String errorMessage = "Could not locate ejb of class [[" + type
                    + "]] ";
            if (name != null && name.length() > 0) {
                errorMessage += "and name [[" + name + "]] ";
            }
            throw new RuntimeException(errorMessage, e);
        }
    }
}