org.apache.wicket.protocol.http.ContextParamWebApplicationFactory.java Source code

Introduction

Here is the source code for org.apache.wicket.protocol.http.ContextParamWebApplicationFactory.java

Source

/*
 * 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.wicket.protocol.http;

import org.apache.wicket.WicketRuntimeException;

/**
 * Factory that creates application objects based on the class name specified in the
 * {@link ContextParamWebApplicationFactory#APP_CLASS_PARAM} context variable.
 * 
 * @author Igor Vaynberg (ivaynberg)
 */
public class ContextParamWebApplicationFactory implements IWebApplicationFactory {
    /**
     * context parameter name that must contain the class name of the application
     */
    public static final String APP_CLASS_PARAM = "applicationClassName";

    /* @see IWebApplicationFactory#createApplication(WicketFilter) */
    @Override
    public WebApplication createApplication(WicketFilter filter) {
        final String applicationClassName = filter.getFilterConfig().getInitParameter(APP_CLASS_PARAM);

        if (applicationClassName == null) {
            throw new WicketRuntimeException("servlet init param [" + APP_CLASS_PARAM
                    + "] is missing. If you are trying to use your own implementation of IWebApplicationFactory and get this message then the servlet init param ["
                    + WicketFilter.APP_FACT_PARAM + "] is missing");
        }

        return createApplication(applicationClassName);
    }

    /**
     * Instantiates the application instance.
     * 
     * @param applicationClassName
     *            the classname of the application to create
     * @return the web application
     */
    protected WebApplication createApplication(final String applicationClassName) {
        try {
            ClassLoader loader = Thread.currentThread().getContextClassLoader();
            if (loader == null) {
                loader = getClass().getClassLoader();
            }

            // see http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6500212
            // final Class<?> applicationClass = loader.loadClass(applicationClassName);
            final Class<?> applicationClass = Class.forName(applicationClassName, false, loader);
            if (WebApplication.class.isAssignableFrom(applicationClass)) {
                // Construct WebApplication subclass
                return (WebApplication) applicationClass.newInstance();
            } else {
                throw new WicketRuntimeException(
                        "Application class " + applicationClassName + " must be a subclass of WebApplication");
            }
        } catch (ClassNotFoundException e) {
            throw new WicketRuntimeException("Unable to create application of class " + applicationClassName, e);
        } catch (InstantiationException e) {
            throw new WicketRuntimeException("Unable to create application of class " + applicationClassName, e);
        } catch (IllegalAccessException e) {
            throw new WicketRuntimeException("Unable to create application of class " + applicationClassName, e);
        } catch (SecurityException e) {
            throw new WicketRuntimeException("Unable to create application of class " + applicationClassName, e);
        }
    }

    /** {@inheritDoc} */
    @Override
    public void destroy(WicketFilter filter) {
    }

}