core/core/src/main/java/org/apache/myfaces/scripting/servlet/CustomChainLoader.java

/*
 * 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.myfaces.scripting.servlet;

import org.apache.commons.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.myfaces.scripting.api.ScriptingWeaver;
import org.apache.myfaces.scripting.core.CoreWeaver;
import org.apache.myfaces.scripting.core.util.WeavingContext;
import org.apache.myfaces.scripting.loaders.groovy.GroovyScriptingWeaver;
import org.apache.myfaces.scripting.loaders.java.JavaScriptingWeaver;
import org.apache.myfaces.shared_impl.util.ClassLoaderExtension;

import javax.servlet.ServletContext;

/**
 * a custom chainloader which adds a groovy loading
 * facility to our myfaces loading plugin system
 *
 * @author Werner Punz
 */
public class CustomChainLoader extends ClassLoaderExtension {

    /*
       * servlet context init var for additional chain loader paths which have
       * higher priority than the default ones 
       */
    static String CUSTOM_LOADER_PATHS = "org.apache.myfaces.scripting.groovy.LOADER_PATHS";
    static String CUSTOM_JAVA_LOADER_PATHS = "org.apache.myfaces.scripting.java.LOADER_PATHS";


    String classRoot = "";
    String scriptingRoot = "";
    ScriptingWeaver scriptingWeaver = null;
    private static final String GROOVY_SOURCE_ROOT = "/WEB-INF/groovy/";
    private static final String JAVA_SOURCE_ROOT = "/WEB-INF/java/";

    Log log = LogFactory.getLog(CustomChainLoader.class);


    //TODO move the entire init code into the weavers
    //every weaver should know itself how to initialize itself

    public CustomChainLoader(ServletContext servletContext) {
        ScriptingWeaver groovyWeaver = new GroovyScriptingWeaver(servletContext);
        ScriptingWeaver javaWeaver = new JavaScriptingWeaver(servletContext);

        setupScriptingPaths(servletContext, groovyWeaver, GROOVY_SOURCE_ROOT, CUSTOM_LOADER_PATHS);
        setupScriptingPaths(servletContext, javaWeaver, JAVA_SOURCE_ROOT, CUSTOM_JAVA_LOADER_PATHS);

        this.scriptingWeaver = new CoreWeaver(groovyWeaver, javaWeaver);
        //we have to store it because our filter
        //does not trigger upon initialisation
        WeavingContext.setWeaver(this.scriptingWeaver);
    }


    private void setupScriptingPaths(ServletContext servletContext, ScriptingWeaver weaver, String contextRootKey, String initParams) {
        String additionalLoaderPaths;

        String contextRoot = servletContext.getRealPath(contextRootKey);
        contextRoot = contextRoot.trim();
        scriptingRoot = contextRoot;

        additionalLoaderPaths = servletContext.getInitParameter(initParams);
        appendAdditionalPaths(additionalLoaderPaths, weaver);
        if (additionalLoaderPaths == null || additionalLoaderPaths.trim().equals("")) {
            weaver.appendCustomScriptPath(scriptingRoot);
            weaver.appendCustomScriptPath(classRoot);
        }
    }

    private void appendAdditionalPaths(String additionalLoaderPaths, ScriptingWeaver workWeaver) {
        if (!StringUtils.isBlank(additionalLoaderPaths)) {
            String[] additionalPaths = additionalLoaderPaths.split(",");
            for (String path : additionalPaths) {
                workWeaver.appendCustomScriptPath(path);
            }
        }
    }

    public Class forName(String name) {
        if (name.endsWith(";")) {
            name = name.substring(1, name.length() - 1);
        }
        if (name == null) {
            return null;
        }
        if (name.startsWith("java.")) /*the entire java namespace is reserved so no use to do a specific classloading check here*/
            return null;
        if (name.startsWith("javax.")) /*the entire java namespace is reserved so no use to do a specific classloading check here*/
            return null;
        else if (name.startsWith("com.sun")) /*internal java specific namespace*/
            return null;
        else if (name.startsWith("sun.")) /*internal java specific namespace*/
            return null;
        else if (name.startsWith("org.apache") && !name.startsWith("org.apache.myfaces")) {
            return null;
        }
        if(name.contains(".Blog")) {
            log.debug("Debugpoint found for Blog");
        }

        return scriptingWeaver.loadScriptingClassFromName(name);
    }

    public ScriptingWeaver getScriptingWeaver() {
        return scriptingWeaver;
    }

    public void setScriptingWeaver(ScriptingWeaver scriptingWeaver) {
        this.scriptingWeaver = scriptingWeaver;
    }

}