/*

  * This software is licensed under the Apache License, Version 2.0

  * (the "License") agreement; 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 net.admin4j.ui.servlets;

 import java.io.IOException;

 import java.lang.management.ManagementFactory;

 import java.util.ArrayList;

 import java.util.Arrays;

 import java.util.HashMap;

 import java.util.List;

 import java.util.Map;

 import java.util.TreeSet;

 import javax.management.AttributeList;

 import javax.management.MBeanInfo;

 import javax.management.MBeanOperationInfo;

 import javax.management.MBeanParameterInfo;

 import javax.management.MBeanServer;

 import javax.management.ObjectInstance;

 import javax.management.ObjectName;

 import javax.management.openmbean.CompositeData;

 import javax.management.openmbean.TabularData;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import net.admin4j.deps.commons.lang3.exception.ExceptionUtils;

 import net.admin4j.util.Admin4jRuntimeException;

 import net.admin4j.util.GuiUtils;

 /**

  * Provides basic display capability for published JMX beans.

  * 

  * <p>You will need to map this servlet to an url pattern (e.g. '/admin4j/jmx').</p>

  * <p>This servlet does <b>not</b> require other web resources.</p>

  * @author D. Ashmore

  * @since 1.0

  */

 @SuppressWarnings("serial")

 public class JmxServlet extends AdminDisplayServlet {

     public static final String PUBLIC_HANDLE="jmx";

         @Override

         protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

             MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();

         Map<String, ObjectInstance> jmxBeanMap = new HashMap<String, ObjectInstance>();

         String selectedJmxBeanStr = request.getParameter("jmxBean");

         ObjectInstance selectedJmxBean = null;

         ObjectInstance jmxBean;

         for (Object obj: mbs.queryMBeans(null, null)) {

             jmxBean = (ObjectInstance)obj;

             jmxBeanMap.put(jmxBean.getObjectName().getCanonicalName(), jmxBean);

             if (jmxBean.getObjectName().getCanonicalName().equals(selectedJmxBeanStr)) {

                 selectedJmxBean = jmxBean;

             }

         }

         String selectedOperationExecStr = request.getParameter("opExec");

         String operationInvokationResultStr = null;

         if (selectedOperationExecStr != null) {

             try {

                 Object invokeReturn = mbs.invoke(selectedJmxBean.getObjectName(), selectedOperationExecStr, null, null);

                 if (invokeReturn != null) {

                     operationInvokationResultStr = invokeReturn.toString();

                 }

                 else operationInvokationResultStr = "Executed successfully.";

             }

             catch (Throwable t) {

                 operationInvokationResultStr = ExceptionUtils.getStackTrace(t);

             }

         }

         AttributeList aList = new AttributeList();

         List<MBeanOperationInfo> oList = new ArrayList<MBeanOperationInfo>();

         MBeanInfo mbInfo = null;

         if (selectedJmxBean != null) {

             try {

                 mbInfo = mbs.getMBeanInfo(selectedJmxBean.getObjectName());

             } catch (Exception e) {

                 throw new Admin4jRuntimeException(e);

             } 

             try {

                 aList = mbs.getAttributes(selectedJmxBean.getObjectName(), findMBeanAttr(mbs, selectedJmxBean.getObjectName()));   

                 oList = Arrays.asList(mbInfo.getOperations());

             } catch (Exception e) {

                 throw new Admin4jRuntimeException(e);

             } 

         }

         Map<String,Object> variableMap = new HashMap<String,Object>();

         variableMap.put("jmxBeanList", new TreeSet<String>(jmxBeanMap.keySet()));

         variableMap.put("selectedJmxBeanName", selectedJmxBeanStr);

         variableMap.put("selectedOperationExecStr", selectedOperationExecStr);

         variableMap.put("mBeanAttributeList", aList);

         variableMap.put("mBeanOperationList", oList);

         variableMap.put("mBeanInfo", mbInfo);

         variableMap.put("operationInvokationResultStr", operationInvokationResultStr);

         variableMap.put("JmxUtils", new JmxUtils());

         this.displayFreeMarkerPage(request, response, "jmxServletDisplay.ftl", variableMap);

         }

         private String[] findMBeanAttr(MBeanServer mbs, ObjectName oName) throws Exception {

                 List<String> nameList = new ArrayList<String>();

                 MBeanInfo mbInfo = mbs.getMBeanInfo(oName);

                 for (int i = 0; i < mbInfo.getAttributes().length; i++) {

                         if (mbInfo.getAttributes()[i].isReadable()) {

                                 nameList.add(mbInfo.getAttributes()[i].getName());

                         }

                 }

                 return (String[])nameList.toArray(new String[0]);

         }

         public static class JmxUtils {

             public boolean isCompositeData(Object obj) {

                 return obj instanceof CompositeData;

             }

             public boolean isTabularData(Object obj) {

             return obj instanceof TabularData;

         }

             public boolean isArray(Object obj) {

                 if (obj == null)  return false;

             return obj.getClass().isArray();

         }

             public boolean isOperationExecutable(Object obj) {

                 if (obj == null)  return false;

                 if (obj instanceof MBeanOperationInfo) {

                     MBeanOperationInfo oInfo = (MBeanOperationInfo)obj;

                     return oInfo.getSignature() == null || (oInfo.getSignature() != null && oInfo.getSignature().length == 0);

                 }

                 return false;

             }

             public String htmlEscape(Object obj) {

                 return new GuiUtils().htmlEscape(obj);

             }

             public List<String> compositeKeyList(Object obj) {

                 List<String> list = new ArrayList<String>();

                 if (obj instanceof CompositeData) {

                     list.addAll( ((CompositeData)obj).getCompositeType().keySet());

                 }

                 return list;

             }

             public Object compositeValue(Object composite, Object key) {

                 if (composite instanceof CompositeData) {

                     return ((CompositeData)composite).get( (String)key);

                 }

                 return null;

             }

             public String formatOperationSignature(MBeanOperationInfo oInfo) {                

                 if (oInfo == null)  return "()";

                 MBeanParameterInfo[] pInfo = oInfo.getSignature();

                 StringBuffer buffer = new StringBuffer(64);

                 buffer.append("(");

                 for (int i = 0; i < pInfo.length; i++) {

                     if (i > 0) buffer.append(", ");

                     buffer.append(pInfo[i].getType());

                     buffer.append(" ");

                     buffer.append(pInfo[i].getName());

                 }

                 buffer.append(")");

                 return buffer.toString();

             }

         }

         /* (non-Javadoc)

      * @see net.admin4j.ui.servlets.Admin4JServlet#getServletLabel()

      */

     @Override

     public String getServletLabel() {

         return "JMX Browser";

     }

 }