primenumberhandler.java

ajax patterns 这是关于ajax设计模式方面的原代码

/*
    Copyright 2006 Christian Gross http://www.devspace.com
    From the book Ajax Patterns and Best Practices

   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 devspace.ajax.infinitedata.primenumbercalculator;
import devspace.ajax.infinitedata.*;
import devspace.ajax.infinitedata.primenumbercalculator.*;
import devspace.ajax.permutations.*;
import devspace.testDrivenDevelopment.tracer.*;
import java.io.*;
import java.util.*;
import javax.servlet.http.*;
import javax.servlet.*;
import xtom.parser.*;

class CookieResolver extends GenericCookieUserResolverImplementation {
    protected String getCookieIdentifier() {
        return "InfiniteData_";
    }
    
    protected String getCookiePath() {
        return "/infinitedata";
    }
}

class Serializer {
    private static Parser getParser(ServletInputStream stream) {
        return new Parser(stream);
    }
    public static ActionData parse( ServletInputStream stream) throws IOException {
        Parser p = getParser( stream);
        XMLTree tree = null;
        Element root = null;
        tree = p.parse();
        root = tree.getRootElement();
        Element transactionIdentifierElement = root.getElementByPath("TransactionIdentifier");
        ActionData data = new ActionData();
        data.setTransactionIdentifier( transactionIdentifierElement.getValue());
        Element number = root.getElementByPath( "Number");
        data.setNumber( new Long( number.getValue()));
        return data;
    }
    public static String generate( PrimeNumberData data) {
        return "<Action>" +
            "<TransactionIdentifier>" + data.getTransactionIdentifier() + "</TransactionIdentifier>" +
            "<Number>" + data.getNumber() + "</Number>" +
            "</Action>";
    }
}
public class PrimeNumberHandler extends RedirectionHttpHandlerBase {
    static Hashtable<String,TaskManagerImplementation> _tasks = new Hashtable<String,TaskManagerImplementation>();
    
    public PrimeNumberHandler() {
        assignUserResolver(new CookieResolver());
    }
    private TaskManagerImplementation getTaskManager() {
        synchronized (_tasks) {
            if (_tasks.containsKey(_identifiedUser.getIdentifier())) {
                GenerateOutput.Write("PrimeNumberHandler.GetTaskManager", "TaskManagerImpl existed and is returned.");
                return _tasks.get(_identifiedUser.getIdentifier());
            }
            else {
                GenerateOutput.Write("PrimeNumberHandler.GetTaskManager", "Created a new TaskManagerImpl instance.");
                TaskManagerImplementation taskmanager = new TaskManagerImplementation();
                _tasks.put(_identifiedUser.getIdentifier(), taskmanager);
                return taskmanager;
            }
        }
    }
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException { {
            TaskManagerImplementation taskManager = getTaskManager();
            if (taskManager != null) {
                GenerateOutput.Write("PrimeNumberHandler.DoGet", "Retrieving the results for a task.");
                Result result = taskManager.getResultWait(10);
                resp.setContentType("text/xml");
                if (result != null) {
                    PrimeNumberData data = (PrimeNumberData)result;
                    String buffer = Serializer.generate(data);
                    GenerateOutput.Write("PrimeNumberHandler.DoGet", "Generated result length (" +
                                         buffer.length() + ") value (" + buffer + ")");
                    resp.addHeader("X-Last-State", "none");
                    resp.getWriter().write(buffer);
                }
                else {
                    if( ! taskManager.anyOutstandingTasks()) {
                        GenerateOutput.Write("PrimeNumberHandler.DoGet", "No outstanding tasks");
                        resp.setStatus( 200, "OK");
                        resp.getWriter().write("<result>No tasks</result>");
                    }
                    else {
                        GenerateOutput.Write("PrimeNumberHandler.DoGet", "No results");
                        resp.setStatus( 200, "OK");
                        resp.getWriter().write("<result>No results</result>");
                    }
                }
            }
            else {
                GenerateOutput.Write("PrimeNumberHandler.DoGet", "Invalid task manager instance");
                resp.setStatus( 200, "OK");
                resp.getWriter().write("<result>Invalid taskManager instance</result>");
            }
        }
    }
    
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
        TaskManagerImplementation taskManager = getTaskManager();
        GenerateOutput.Write("PrimeNumberHandler.DoPost", "Executing a new task.");
        ActionData data = Serializer.parse(req.getInputStream());
        GenerateOutput.Write("PrimeNumberHandler.DoPost", "Data sent(" + data.toString() + ")");
        taskManager.addTask(
            new Calculator(data.getNumber(), data.getTransactionIdentifier()));
        taskManager.runThreadedTasks();
    }
    
    protected String getBaseURL() {
        return "/infinitedata/primenumbercalculator";
    }
    
    protected String getURLEnding() {
        return _identifiedUser.getIdentifier();
    }
    
    
}