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From cos...@apache.org
Subject cvs commit: jakarta-tomcat-connectors/util/java/org/apache/tomcat/util/mx DynamicMBeanProxy.java
Date Wed, 05 Jun 2002 21:19:48 GMT
costin      2002/06/05 14:19:48

  Added:       util/java/org/apache/tomcat/util/mx DynamicMBeanProxy.java
  Log:
  Initial version of the DynamicMBean proxy.
  
  This version is supports only basic operations ( get/set, methods with no params )
  using introspection.
  
  Later we may do fancier stuff - like extracting the description and
  filter the exposed attributes ( i.e. use a config file ), but what's
  important is to have it working ( well enough ) with minimal effort
  and to support existing components without anything special
  
  ( i.e. easy to do simple operations ).
  
  Advanced things depend on some build changes ( my preference is to use
  @jmx: javadoc comments - and that requires deps on xdoclet or similar tool ).
  
  Revision  Changes    Path
  1.1                  jakarta-tomcat-connectors/util/java/org/apache/tomcat/util/mx/DynamicMBeanProxy.java
  
  Index: DynamicMBeanProxy.java
  ===================================================================
  /*
   * ====================================================================
   *
   * The Apache Software License, Version 1.1
   *
   * Copyright (c) 1999 The Apache Software Foundation.  All rights 
   * reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer. 
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. The end-user documentation included with the redistribution, if
   *    any, must include the following acknowlegement:  
   *       "This product includes software developed by the 
   *        Apache Software Foundation (http://www.apache.org/)."
   *    Alternately, this acknowlegement may appear in the software itself,
   *    if and wherever such third-party acknowlegements normally appear.
   *
   * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
   *    Foundation" must not be used to endorse or promote products derived
   *    from this software without prior written permission. For written 
   *    permission, please contact apache@apache.org.
   *
   * 5. Products derived from this software may not be called "Apache"
   *    nor may "Apache" appear in their names without prior written
   *    permission of the Apache Group.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   * [Additional notices, if required by prior licensing conditions]
   *
   */ 
  
  package org.apache.tomcat.util.mx;
  
  import java.io.*;
  import java.net.*;
  import java.lang.reflect.*;
  import java.util.*;
  import javax.management.*;
  
  import org.apache.tomcat.util.IntrospectionUtils;
  
  /**
   * DynamicMBean implementation using introspection to manage any
   * component that follows the bean/ant/Interceptor/Valve/Jk2 patterns.
   *
   * The class will wrap any component conforming to those patterns.
   * 
   * @author Costin Manolache
   */
  public class DynamicMBeanProxy implements DynamicMBean {
      Object real;
  
      Method methods[];
  
      Hashtable attMap=new Hashtable();
  
      // key: attribute val: getter method
      Hashtable getAttMap=new Hashtable();
  
      // key: attribute val: setter method
      Hashtable setAttMap=new Hashtable();
  
      // key: operation val: invoke method
      Hashtable invokeAttMap=new Hashtable();
  
      /** Create a Dynamic proxy, using introspection to manage a
       *  real tomcat component.
       */
      public DynamicMBeanProxy() {
          
      }
  
      /** Set the managed object.
       *
       * @todo Read an XML ( or .properties ) file containing descriptions,
       *       generated from source comments
       * @todo Also filter methods based on config ( hide methods/attributes )
       * @todo Adapters for notifications ( Interceptor hooks, etc ). 
       */
      public void setReal( Object realBean ) {
          real=realBean;
  
          methods = real.getClass().getMethods();
          for (int j = 0; j < methods.length; ++j) {
              String name=methods[j].getName();
              
              if( name.startsWith( "get" ) ) {
                  if( methods[j].getParameterTypes().length != 0 ) {
                      continue;
                  }
                  if( ! Modifier.isPublic( methods[j].getModifiers() ) )
                      continue;
                  Class ret=methods[j].getReturnType();
                  if( ret != String.class &&
                      ret != Integer.class &&
                      ret != Boolean.class ) {
                      continue;
                  }
                  name=unCapitalize( name.substring(3));
  
                  getAttMap.put( name, methods[j] );
                  // just a marker, we don't use the value 
                  attMap.put( name, methods[j] );
              } else if( name.startsWith( "is" ) ) {
                  // not used in our code. Add later
  
              } else if( name.startsWith( "set" ) ) {
                  Class params[]=methods[j].getParameterTypes();
                  if( params.length != 1 ) {
                      continue;
                  }
                  if( ! Modifier.isPublic( methods[j].getModifiers() ) )
                      continue;
                  Class ret=params[0];
                  if( ret != String.class &&
                      ret != Integer.class &&
                      ret != Boolean.class ) {
                      continue;
                  }
                  name=unCapitalize( name.substring(3));
                  setAttMap.put( name, methods[j] );
                  attMap.put( name, methods[j] );
              } else {
                  if( methods[j].getParameterTypes().length != 0 ) {
                      continue;
                  }
                  if( methods[j].getDeclaringClass() == Object.class )
                      continue;
                  if( ! Modifier.isPublic( methods[j].getModifiers() ) )
                      continue;
                  invokeAttMap.put( name, methods[j]);
              }
              
          }
      }
  
      /**
       * @todo Find if the 'className' is the name of the MBean or
       *       the real class ( I suppose first )
       * @todo Read (optional) descriptions from a .properties, generated
       *       from source
       * @todo Deal with constructors
       *       
       */
      public MBeanInfo getMBeanInfo() {
          try {
              MBeanAttributeInfo attributes[]=new MBeanAttributeInfo[attMap.size()];
  
              Enumeration en=attMap.keys();
              int i=0;
              while( en.hasMoreElements() ) {
                  String name=(String)en.nextElement();
                  attributes[i++]=new MBeanAttributeInfo(name, "Attribute " + name ,
                                                         (Method)getAttMap.get(name),
                                                         (Method)setAttMap.get(name));
              }
              
              MBeanOperationInfo operations[]=new MBeanOperationInfo[invokeAttMap.size()];
              
              en=invokeAttMap.keys();
              i=0;
              while( en.hasMoreElements() ) {
                  String name=(String)en.nextElement();
                  Method m=(Method)invokeAttMap.get(name);
                  if( m!=null && name != null ) {
                      operations[i++]=new MBeanOperationInfo(name, m);
                  } else {
                      System.out.println("Null arg " + name + " " + m );
                  }
              }
              
              log.info(real.getClass().getName() +  "getMBeanInfo ");
              return new MBeanInfo( this.getClass().getName(),
                                    "Management bean for " + real.getClass().getName(),
                                    attributes,
                                    new MBeanConstructorInfo[0],
                                    operations,
                                    new MBeanNotificationInfo[0]);
          } catch( Exception ex ) {
              ex.printStackTrace();
              return null;
          }
      }
  
      static final Object[] NO_ARGS_PARAM=new Object[0];
      
      public Object getAttribute(String attribute)
          throws AttributeNotFoundException, MBeanException, ReflectionException
      {
          Method m=(Method)getAttMap.get( attribute );
          if( m==null ) throw new AttributeNotFoundException(attribute);
  
          try {
              log.info(real.getClass().getName() +  "getAttribute " + attribute);
              return m.invoke(real, NO_ARGS_PARAM );
          } catch( IllegalAccessException ex ) {
              ex.printStackTrace();
              throw new MBeanException( ex );
          } catch( InvocationTargetException ex1 ) {
              ex1.printStackTrace();
              throw new MBeanException( ex1 );
          }
      }
      
      public void setAttribute(Attribute attribute)
          throws AttributeNotFoundException, InvalidAttributeValueException, MBeanException,
ReflectionException
      {
          Method m=(Method)setAttMap.get( attribute.getName() );
          if( m==null ) throw new AttributeNotFoundException(attribute.getName());
  
          try {
              log.info(real.getClass().getName() +  "setAttribute " + attribute.getName());
              m.invoke(real, new Object[] { attribute.getValue() } );
          } catch( IllegalAccessException ex ) {
              ex.printStackTrace();
              throw new MBeanException( ex );
          } catch( InvocationTargetException ex1 ) {
              ex1.printStackTrace();
              throw new MBeanException( ex1 );
          }
      }
      
      /**
       * Invoke a method. Only no param methods are supported at the moment
       * ( init, start, execute, etc ) ( that's the most common pattern we have
       *  in tomcat/ant/etc )
       *
       * @todo Implement invoke for methods with more arguments.
       */
      public Object invoke(String method, Object[] arguments, String[] params)
          throws MBeanException, ReflectionException
      {
          Method m=(Method)invokeAttMap.get( method );
          if( m==null ) return null;
  
          try {
              log.info(real.getClass().getName() +  "invoke " + m.getName());
              return m.invoke(real, NO_ARGS_PARAM );
          } catch( IllegalAccessException ex ) {
              throw new MBeanException( ex );
          } catch( InvocationTargetException ex1 ) {
              throw new MBeanException( ex1 );
          }
      }
  
  
      // -------------------- Auxiliary methods --------------------
      
      public AttributeList setAttributes(AttributeList attributes) {
          Iterator attE=attributes.iterator();
          while( attE.hasNext() ) {
              Attribute att=(Attribute)attE.next();
  
              try {
                  setAttribute( att );
              } catch( Exception ex ) {
                  ex.printStackTrace();
              }
          }
          return attributes;
      }
  
      public AttributeList getAttributes(String[] attributes) {
          AttributeList al=new AttributeList();
          if( attributes==null ) return null;
          
          for( int i=0; i<attributes.length; i++ ) {
              try {
                  Attribute att=new Attribute( attributes[i], getAttribute( attributes[i]
));
                  al.add( att );
              } catch( Exception ex ) {
                  ex.printStackTrace();
              }
          }
          return al;
      }
      
  
      // -------------------- Utils --------------------
  
      public static String unCapitalize(String name) {
  	if (name == null || name.length() == 0) {
  	    return name;
  	}
  	char chars[] = name.toCharArray();
  	chars[0] = Character.toLowerCase(chars[0]);
  	return new String(chars);
      }
  
      private static org.apache.commons.logging.Log log=
          org.apache.commons.logging.LogFactory.getLog( DynamicMBeanProxy.class );
  
  }
  
  
  

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