defaultremoter.java

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/*
 * Copyright 2005 Joe Walker
 *
 * Licensed 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.directwebremoting.impl;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import org.directwebremoting.AjaxFilter;
import org.directwebremoting.AjaxFilterChain;
import org.directwebremoting.WebContext;
import org.directwebremoting.WebContextFactory;
import org.directwebremoting.extend.AccessControl;
import org.directwebremoting.extend.AjaxFilterManager;
import org.directwebremoting.extend.Call;
import org.directwebremoting.extend.Calls;
import org.directwebremoting.extend.Converter;
import org.directwebremoting.extend.ConverterManager;
import org.directwebremoting.extend.Creator;
import org.directwebremoting.extend.CreatorManager;
import org.directwebremoting.extend.NamedConverter;
import org.directwebremoting.extend.Property;
import org.directwebremoting.extend.EnginePrivate;
import org.directwebremoting.extend.Remoter;
import org.directwebremoting.extend.Replies;
import org.directwebremoting.extend.Reply;
import org.directwebremoting.util.Continuation;
import org.directwebremoting.util.JavascriptUtil;
import org.directwebremoting.util.LocalUtil;
import org.directwebremoting.util.Logger;

/**
 * In implementation of Remoter that delegates requests to a set of Modules
 * @author Joe Walker [joe at getahead dot ltd dot uk]
 * @author Mike Wilson
 */
public class DefaultRemoter implements Remoter
{
    /* (non-Javadoc)
     * @see org.directwebremoting.Remoter#generateInterfaceScript(java.lang.String, java.lang.String)
     */
    public String generateInterfaceScript(String scriptName, String path) throws SecurityException
    {
        String actualPath = path;
        if (overridePath != null)
        {
            actualPath = overridePath;
        }

        StringBuffer buffer = new StringBuffer();

        // Output the class definitions for the converted objects
        Collection converterMatches = converterManager.getConverterMatchStrings();
        Iterator it = converterMatches.iterator();
        while (it.hasNext())
        {
            String match = (String) it.next();

            try
            {
                StringBuffer paramBuffer = new StringBuffer();

                Converter conv = converterManager.getConverterByMatchString(match);
                // We will only generate JavaScript classes for compound objects/beans
                if (conv instanceof NamedConverter)
                {
                    NamedConverter boConv = (NamedConverter) conv;
                    String jsClassName = boConv.getJavascript();

                    // We need a configured JavaScript class name
                    if (jsClassName != null && !jsClassName.equals(""))
                    {
                        // Wildcard match strings are currently not supported
                        if (match.indexOf("*") == -1)
                        {
                            paramBuffer.append('\n');

                            // output: if (typeof <class> != "function") { var <class> = function() {
                            paramBuffer.append("if (typeof " + jsClassName + " != \"function\") {\n");
                            paramBuffer.append("  function " + jsClassName + "() {\n");

                            // output: this.<property> = <init-value>;
                            Class mappedType;
                            try
                            {
                                mappedType = LocalUtil.classForName(match);
                            }
                            catch (ClassNotFoundException ex)
                            {
                                throw new IllegalArgumentException(ex.getMessage());
                            }

                            Map properties = boConv.getPropertyMapFromClass(mappedType, true, true);
                            for (Iterator pit = properties.entrySet().iterator(); pit.hasNext();)
                            {
                                Map.Entry entry = (Map.Entry) pit.next();
                                String name = (String) entry.getKey();
                                Property property = (Property) entry.getValue();
                                Class propType = property.getPropertyType();

                                // Property name
                                paramBuffer.append("    this." + name + " = ");

                                // Default property values
                                if (propType.isArray())
                                {
                                    paramBuffer.append("[]");
                                }
                                else if (propType == boolean.class)
                                {
                                    paramBuffer.append("false");
                                }
                                else if (propType.isPrimitive())
                                {
                                    paramBuffer.append("0");
                                }
                                else
                                {
                                    paramBuffer.append("null");
                                }

                                paramBuffer.append(";\n");
                            }

                            paramBuffer.append("  }\n");
                            paramBuffer.append("}\n");
                        }
                    }
                }

                buffer.append(paramBuffer.toString());
            }
            catch (Exception ex)
            {
                log.warn("Failed to create parameter declaration for " + match, ex);
                buffer.append("// Missing parameter declaration for " + match + ". See the server logs for details.");
            }
        }

        Creator creator = creatorManager.getCreator(scriptName);

        buffer.append('\n');

        String init = EnginePrivate.getEngineInitScript();
        buffer.append(init);

        buffer.append("if (" + scriptName + " == null) var " + scriptName + " = {};\n");
        buffer.append(scriptName + "._path = '" + actualPath + "';\n");

        Method[] methods = creator.getType().getMethods();
        for (int i = 0; i < methods.length; i++)
        {
            Method method = methods[i];
            String methodName = method.getName();

            // We don't need to check accessControl.getReasonToNotExecute()
            // because the checks are made by the execute() method, but we do
            // check if we can display it
            try
            {
                accessControl.assertIsDisplayable(creator, scriptName, method);
            }
            catch (SecurityException ex)
            {
                if (!allowImpossibleTests)
                {
                    continue;
                }
            }

            // Is it on the list of banned names
            if (JavascriptUtil.isReservedWord(methodName))
            {
                continue;
            }

            // Check to see if the creator is reloadable
            // If it is, then do not cache the generated Javascript
            String script;
            if (!creator.isCacheable())
            {
                script = getMethodJS(scriptName, method);
            }
            else
            {
                String key = scriptName + "." + method.getName();

                // For optimal performance we might use the Memoizer pattern
                // JCiP#108 however performance isn't a big issue and we are
                // prepared to cope with getMethodJS() being run more than once.
                script = (String) methodCache.get(key);
                if (script == null)
                {
                    script = getMethodJS(scriptName, method);
                    methodCache.put(key, script);
                }
            }

            buffer.append(script);
        }

        return buffer.toString();
    }

    /**
     * Generates Javascript for a given Java method
     * @param scriptName  Name of the Javascript file, sans ".js" suffix
     * @param method Target method
     * @return Javascript implementing the DWR call for the target method
     */
    private String getMethodJS(String scriptName, Method method)
    {
        StringBuffer buffer = new StringBuffer();

        String methodName = method.getName();
        buffer.append(scriptName + '.' + methodName + " = function(");
        Class[] paramTypes = method.getParameterTypes();
        for (int j = 0; j < paramTypes.length; j++)
        {
            if (!LocalUtil.isServletClass(paramTypes[j]))
            {
                buffer.append("p" + j + ", ");
            }
        }

        buffer.append("callback) {\n");

        String executeFunctionName = EnginePrivate.getExecuteFunctionName();
        buffer.append("  " + executeFunctionName + "(" + scriptName + "._path, '" + scriptName + "', '" + methodName + "\', ");
        for (int j = 0; j < paramTypes.length; j++)
        {
            if (LocalUtil.isServletClass(paramTypes[j]))
            {
                buffer.append("false, ");
            }
            else
            {
                buffer.append("p" + j + ", ");
            }
        }

        buffer.append("callback);\n");
        buffer.append("}\n");

        return buffer.toString();
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.Remoter#execute(org.directwebremoting.Calls)
     */
    public Replies execute(Calls calls)
    {
        Replies replies = new Replies(calls.getBatchId());

        int callCount = calls.getCallCount();
        if (callCount > maxCallCount)
        {
            log.error("Call count for batch exceeds maxCallCount. Add an init-param of maxCallCount to increase this limit");
            throw new SecurityException("Call count for batch is too high");
        }

        for (int callNum = 0; callNum < callCount; callNum++)
        {