package org.apache.ojb.broker.locking;

 /* Copyright 2004-2005 The Apache Software Foundation

  *

  * 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.

  */

 import javax.servlet.ServletException;

 import javax.servlet.ServletConfig;

 import javax.servlet.http.HttpServlet;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.ObjectInputStream;

 import java.io.ObjectOutputStream;

 import java.io.PrintWriter;

 import org.apache.commons.lang.math.NumberUtils;

 import org.apache.ojb.broker.util.ClassHelper;

 /**

  * @author Thomas Mahler

  */

 public class LockManagerServlet extends HttpServlet

 {

     protected static LockManager lockmanager;

     static final String STR_LOCK_TIMEOUT = "lockTimeout";

     static final String STR_BLOCK_TIMEOUT = "blockTimeout";

     static final String STR_LOCK_MANAGER = "lockManager";

     private static long numRequests;

     private static Throwable lastError = null;

     public void init(ServletConfig servletConfig) throws ServletException

     {

         super.init(servletConfig);

         // if lock manager was instantiated not yet

         if(lockmanager == null)

         {

             lastError = null;

             numRequests = 0;

             String strLockManager = servletConfig.getInitParameter(STR_LOCK_MANAGER);

             try

             {

                 lockmanager = (LockManager) (strLockManager != null ?

                         ClassHelper.newInstance(strLockManager) : ClassHelper.newInstance(LockManagerInMemoryImpl.class));

             }

             catch(Exception e)

             {

                 lastError = new LockRuntimeException("Can't instance lock manager, init parameter 'lockManager': " + strLockManager);

                 e.printStackTrace();

             }

             String strTimeout = servletConfig.getInitParameter(STR_LOCK_TIMEOUT);

             if(NumberUtils.isNumber(strTimeout))

             {

                 try

                 {

                     Long lockTimeout = NumberUtils.createLong(strTimeout);

                     lockmanager.setLockTimeout(lockTimeout.longValue());

                 }

                 catch(Exception e)

                 {

                     if(lastError == null)

                     {

                         lastError = new LockRuntimeException("Can't convert 'lockTimeout' init parameter: " + strTimeout);

                     }

                     e.printStackTrace();

                 }

             }

             String strBlock = servletConfig.getInitParameter(STR_BLOCK_TIMEOUT);

             if(NumberUtils.isNumber(strBlock))

             {

                 try

                 {

                     Long blockTimeout = NumberUtils.createLong(strBlock);

                     lockmanager.setLockTimeout(blockTimeout.longValue());

                 }

                 catch(Exception e)

                 {

                     if(lastError == null)

                     {

                         lastError = new LockRuntimeException("Can't convert 'blockTimeout' init parameter: " + strBlock);

                     }

                     e.printStackTrace();

                 }

             }

         }

     }

     /* (non-Javadoc)

      * @see javax.servlet.http.HttpServlet#doGet(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)

      */

     protected void doGet(HttpServletRequest request, HttpServletResponse response)

             throws ServletException, IOException

     {

         response.setContentType("text/html");

         response.setHeader("Pragma", "no-cache");

         PrintWriter out = response.getWriter();

         out.println("<html><head><title>OJB Distributed Locking Servlet Status Page</title>");

         out.println("</head><body><h1>OJB Distributed Locking Servlet</h1>");

         out.println("The servlet is running.<p>");

         if(lastError == null)

         {

             out.println("The LockServer is running.<p>");

             out.println("LockManager info: " + lockmanager.getLockInfo() + "<p>");

             out.println("Processed Lock Request: " + numRequests + "<p>");

         }

         else

         {

             out.println("<h2>The LockServer has a problem!</h2>");

             out.println("The error message is:<p>");

             out.println(lastError.getMessage() + "<p>");

             lastError.printStackTrace(out);

             lastError = null;

         }

         out.println("</body></html>");

     }

     /* (non-Javadoc)

      * @see javax.servlet.http.HttpServlet#doPost(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)

      */

     protected void doPost(HttpServletRequest request, HttpServletResponse response)

             throws ServletException, IOException

     {

         // update counter

         numRequests++;

         try

         {

             // read request:

             LockManagerRemoteImpl.LockInfo info = (LockManagerRemoteImpl.LockInfo) buildObjectFromRequest(request);

             Object result = null;

             // now execute the command specified by the selector

             try

             {

                 switch(info.methodName)

                 {

                     case LockManagerRemoteImpl.METHOD_READ_LOCK:

                         {

                             result = new Boolean(lockmanager.readLock(info.key, info.resourceId, info.isolationLevel));

                             break;

                         }

                     case LockManagerRemoteImpl.METHOD_RELEASE_SINGLE_LOCK:

                         {

                             result = new Boolean(lockmanager.releaseLock(info.key, info.resourceId));

                             break;

                         }

                     case LockManagerRemoteImpl.METHOD_RELEASE_LOCKS:

                         {

                             lockmanager.releaseLocks(info.key);

                             result = Boolean.TRUE;

                             break;

                         }

                     case LockManagerRemoteImpl.METHOD_WRITE_LOCK:

                         {

                             result = new Boolean(lockmanager.writeLock(info.key, info.resourceId,

                                     info.isolationLevel));

                             break;

                         }

                     case LockManagerRemoteImpl.METHOD_UPGRADE_LOCK:

                         {

                             result = new Boolean(lockmanager.upgradeLock(info.key, info.resourceId, info.isolationLevel));

                             break;

                         }

                     case LockManagerRemoteImpl.METHOD_CHECK_READ:

                         {

                             result = new Boolean(lockmanager.hasRead(info.key, info.resourceId));

                             break;

                         }

                     case LockManagerRemoteImpl.METHOD_CHECK_WRITE:

                         {

                             result = new Boolean(lockmanager.hasWrite(info.key, info.resourceId));

                             break;

                         }

                     case LockManagerRemoteImpl.METHOD_CHECK_UPGRADE:

                         {

                             result = new Boolean(lockmanager.hasUpgrade(info.key, info.resourceId));

                             break;

                         }

                     case LockManagerRemoteImpl.METHOD_LOCK_INFO:

                         {

                             result = lockmanager.getLockInfo();

                             break;

                         }

                     case LockManagerRemoteImpl.METHOD_LOCK_TIMEOUT:

                         {

                             result = new Long(lockmanager.getLockTimeout());

                             break;

                         }

                     case LockManagerRemoteImpl.METHOD_BLOCK_TIMEOUT:

                         {

                             result = new Long(lockmanager.getBlockTimeout());

                             break;

                         }

 //                    case LockManagerRemoteImpl.METHOD_LOCK_TIMEOUT_SET:

 //                        {

 //                            lockmanager.setLockTimeout(info.lockTimeout);

 //                            break;

 //                        }

 //

 //                    case LockManagerRemoteImpl.METHOD_BLOCK_TIMEOUT_SET:

 //                        {

 //                            lockmanager.setBlockTimeout(info.blockTimeout);

 //                            break;

 //                        }

                     default :

                         {

                             throw new LockRuntimeException("Unknown command:" + info.methodName);

                         }

                 }

             }

             catch(RuntimeException e)

             {

                 result = new LockRuntimeException("Error while invoke specified method in servlet.", e);

             }

             ObjectOutputStream oos = new ObjectOutputStream(response.getOutputStream());

             oos.writeObject(result);

             oos.flush();

             oos.close();

         }

         catch(Throwable t)

         {

             lastError = t;

             t.printStackTrace();

         }

     }

     private Object buildObjectFromRequest(HttpServletRequest request) throws IOException, ClassNotFoundException

     {

         Object obj = null;

         // get the body of the request as binary data

         InputStream is = request.getInputStream();

         ObjectInputStream objInputStream = new ObjectInputStream(is);

         obj = objInputStream.readObject();

         objInputStream.close();

         is.close();

         return obj;

     }

 }