basemodelmbean.java

业界著名的tomcat服务器的最新6.0的源代码。

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.tomcat.util.modeler;


import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Iterator;

import javax.management.Attribute;
import javax.management.AttributeChangeNotification;
import javax.management.AttributeList;
import javax.management.AttributeNotFoundException;
import javax.management.DynamicMBean;
import javax.management.InstanceNotFoundException;
import javax.management.InvalidAttributeValueException;
import javax.management.ListenerNotFoundException;
import javax.management.MBeanException;
import javax.management.MBeanInfo;
import javax.management.MBeanNotificationInfo;
import javax.management.MBeanRegistration;
import javax.management.MBeanServer;
import javax.management.Notification;
import javax.management.NotificationFilter;
import javax.management.NotificationListener;
import javax.management.ObjectName;
import javax.management.ReflectionException;
import javax.management.RuntimeErrorException;
import javax.management.RuntimeOperationsException;
import javax.management.modelmbean.InvalidTargetObjectTypeException;
import javax.management.modelmbean.ModelMBeanNotificationBroadcaster;

import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;

/*
 * Changes from commons.modeler:
 * 
 *  - use DynamicMBean
 *  - remove methods not used in tomcat and redundant/not very generic
 *  - must be created from the ManagedBean - I don't think there were any direct
 *    uses, but now it is required.
 *  - some of the gratuituous flexibility removed - instead this is more predictive and
 *    strict with the use cases.
 *  - all Method and metadata is stored in ManagedBean. BaseModelBMean and ManagedBean act
 *    like Object and Class. 
 *  - setModelMBean is no longer called on resources ( not used in tomcat )
 *  - no caching of Methods for now - operations and setters are not called repeatedly in most 
 *  management use cases. Getters should't be called very frequently either - and even if they
 *  are, the overhead of getting the method should be small compared with other JMX costs ( RMI, etc ).
 *  We can add getter cache if needed.
 *  - removed unused constructor, fields
 *  
 *  TODO:
 *   - clean up catalina.mbeans, stop using weird inheritance
 */

/**
 * <p>Basic implementation of the <code>DynamicMBean</code> interface, which
 * supports the minimal requirements of the interface contract.</p>
 *
 * <p>This can be used directly to wrap an existing java bean, or inside
 * an mlet or anywhere an MBean would be used. 
 *
 * Limitations:
 * <ul>
 * <li>Only managed resources of type <code>objectReference</code> are
 *     supportd.</li>
 * <li>Caching of attribute values and operation results is not supported.
 *     All calls to <code>invoke()</code> are immediately executed.</li>
 * <li>Persistence of MBean attributes and operations is not supported.</li>
 * <li>All classes referenced as attribute types, operation parameters, or
 *     operation return values must be one of the following:
 *     <ul>
 *     <li>One of the Java primitive types (boolean, byte, char, double,
 *         float, integer, long, short).  Corresponding value will be wrapped
 *         in the appropriate wrapper class automatically.</li>
 *     <li>Operations that return no value should declare a return type of
 *         <code>void</code>.</li>
 *     </ul>
 * <li>Attribute caching is not supported</li>
 * </ul>
 *
 * @author Craig R. McClanahan
 * @author Costin Manolache
 */
public class BaseModelMBean implements DynamicMBean, MBeanRegistration, ModelMBeanNotificationBroadcaster {
    private static Log log = LogFactory.getLog(BaseModelMBean.class);

    // ----------------------------------------------------------- Constructors

    /**
     * Construct a <code>ModelMBean</code> with default
     * <code>ModelMBeanInfo</code> information.
     *
     * @exception MBeanException if the initializer of an object
     *  throws an exception
     * @exception RuntimeOperationsException if an IllegalArgumentException
     *  occurs
     */
    protected BaseModelMBean() throws MBeanException, RuntimeOperationsException {
        super();
    }

    // ----------------------------------------------------- Instance Variables

    protected ObjectName oname=null;

    /**
     * Notification broadcaster for attribute changes.
     */
    protected BaseNotificationBroadcaster attributeBroadcaster = null;

    /**
     * Notification broadcaster for general notifications.
     */
    protected BaseNotificationBroadcaster generalBroadcaster = null;
    
    /** Metadata for the mbean instance.
     */
    protected ManagedBean managedBean = null;

    /**
     * The managed resource this MBean is associated with (if any).
     */
    protected Object resource = null;

    // --------------------------------------------------- DynamicMBean Methods
    // TODO: move to ManagedBean
    static final Object[] NO_ARGS_PARAM=new Object[0];
    static final Class[] NO_ARGS_PARAM_SIG=new Class[0];
    
    protected String resourceType = null;

    // key: operation val: invoke method
    //private Hashtable invokeAttMap=new Hashtable();

    /**
     * Obtain and return the value of a specific attribute of this MBean.
     *
     * @param name Name of the requested attribute
     *
     * @exception AttributeNotFoundException if this attribute is not
     *  supported by this MBean
     * @exception MBeanException if the initializer of an object
     *  throws an exception
     * @exception ReflectionException if a Java reflection exception
     *  occurs when invoking the getter
     */
    public Object getAttribute(String name)
        throws AttributeNotFoundException, MBeanException,
            ReflectionException {
        // Validate the input parameters
        if (name == null)
            throw new RuntimeOperationsException
                (new IllegalArgumentException("Attribute name is null"),
                 "Attribute name is null");

        if( (resource instanceof DynamicMBean) && 
             ! ( resource instanceof BaseModelMBean )) {
            return ((DynamicMBean)resource).getAttribute(name);
        }
        
        Method m=managedBean.getGetter(name, this, resource);
        Object result = null;
        try {
            Class declaring=m.getDeclaringClass();
            // workaround for catalina weird mbeans - the declaring class is BaseModelMBean.
            // but this is the catalina class.
            if( declaring.isAssignableFrom(this.getClass()) ) {
                result = m.invoke(this, NO_ARGS_PARAM );
            } else {
                result = m.invoke(resource, NO_ARGS_PARAM );
            }
        } catch (InvocationTargetException e) {
            Throwable t = e.getTargetException();
            if (t == null)
                t = e;
            if (t instanceof RuntimeException)
                throw new RuntimeOperationsException
                    ((RuntimeException) t, "Exception invoking method " + name);
            else if (t instanceof Error)
                throw new RuntimeErrorException
                    ((Error) t, "Error invoking method " + name);
            else
                throw new MBeanException
                    (e, "Exception invoking method " + name);
        } catch (Exception e) {
            throw new MBeanException
                (e, "Exception invoking method " + name);
        }

        // Return the results of this method invocation
        // FIXME - should we validate the return type?
        return (result);
    }


    /**
     * Obtain and return the values of several attributes of this MBean.
     *
     * @param names Names of the requested attributes
     */
    public AttributeList getAttributes(String names[]) {

        // Validate the input parameters
        if (names == null)
            throw new RuntimeOperationsException
                (new IllegalArgumentException("Attribute names list is null"),
                 "Attribute names list is null");

        // Prepare our response, eating all exceptions
        AttributeList response = new AttributeList();
        for (int i = 0; i < names.length; i++) {
            try {
                response.add(new Attribute(names[i],getAttribute(names[i])));
            } catch (Exception e) {
                ; // Not having a particular attribute in the response
                ; // is the indication of a getter problem
            }
        }
        return (response);

    }

    public void setManagedBean(ManagedBean managedBean) {
        this.managedBean = managedBean;
    }

    /**
     * Return the <code>MBeanInfo</code> object for this MBean.
     */
    public MBeanInfo getMBeanInfo() {
        return managedBean.getMBeanInfo();
    }


    /**
     * Invoke a particular method on this MBean, and return any returned
     * value.
     *
     * <p><strong>IMPLEMENTATION NOTE</strong> - This implementation will
     * attempt to invoke this method on the MBean itself, or (if not
     * available) on the managed resource object associated with this
     * MBean.</p>
     *
     * @param name Name of the operation to be invoked
     * @param params Array containing the method parameters of this operation
     * @param signature Array containing the class names representing
     *  the signature of this operation
     *
     * @exception MBeanException if the initializer of an object
     *  throws an exception
     * @exception ReflectioNException if a Java reflection exception
     *  occurs when invoking a method
     */
    public Object invoke(String name, Object params[], String signature[])
        throws MBeanException, ReflectionException 
    {
        if( (resource instanceof DynamicMBean) && 
             ! ( resource instanceof BaseModelMBean )) {
            return ((DynamicMBean)resource).invoke(name, params, signature);
        }
    
        // Validate the input parameters
        if (name == null)
            throw new RuntimeOperationsException
                (new IllegalArgumentException("Method name is null"),
                 "Method name is null");

        if( log.isDebugEnabled()) log.debug("Invoke " + name);
	MethodKey mkey = new MethodKey(name, signature);
        Method method= managedBean.getInvoke(name, params, signature, this, resource);
        
        // Invoke the selected method on the appropriate object
        Object result = null;
        try {
            if( method.getDeclaringClass().isAssignableFrom( this.getClass()) ) {
                result = method.invoke(this, params );
            } else {
                result = method.invoke(resource, params);
            }
        } catch (InvocationTargetException e) {
            Throwable t = e.getTargetException();
            log.error("Exception invoking method " + name , t );
            if (t == null)
                t = e;
            if (t instanceof RuntimeException)
                throw new RuntimeOperationsException
                    ((RuntimeException) t, "Exception invoking method " + name);
            else if (t instanceof Error)
                throw new RuntimeErrorException
                    ((Error) t, "Error invoking method " + name);
            else
                throw new MBeanException
                    ((Exception)t, "Exception invoking method " + name);
        } catch (Exception e) {
            log.error("Exception invoking method " + name , e );
            throw new MBeanException
                (e, "Exception invoking method " + name);
        }

        // Return the results of this method invocation
        // FIXME - should we validate the return type?
        return (result);

    }

    static Class getAttributeClass(String signature)
        throws ReflectionException
    {
        if (signature.equals(Boolean.TYPE.getName()))
            return Boolean.TYPE;
        else if (signature.equals(Byte.TYPE.getName()))
            return Byte.TYPE;
        else if (signature.equals(Character.TYPE.getName()))
            return Character.TYPE;
        else if (signature.equals(Double.TYPE.getName()))
            return Double.TYPE;
        else if (signature.equals(Float.TYPE.getName()))
            return Float.TYPE;
        else if (signature.equals(Integer.TYPE.getName()))
            return Integer.TYPE;
        else if (signature.equals(Long.TYPE.getName()))
            return Long.TYPE;
        else if (signature.equals(Short.TYPE.getName()))
            return Short.TYPE;
        else {
            try {
                ClassLoader cl=Thread.currentThread().getContextClassLoader();
                if( cl!=null )
                    return cl.loadClass(signature); 
            } catch( ClassNotFoundException e ) {
            }
            try {
                return Class.forName(signature);
            } catch (ClassNotFoundException e) {
                throw new ReflectionException
                    (e, "Cannot find Class for " + signature);
            }
        }
    }

    /**
     * Set the value of a specific attribute of this MBean.
     *
     * @param attribute The identification of the attribute to be set
     *  and the new value
     *
     * @exception AttributeNotFoundException if this attribute is not
     *  supported by this MBean
     * @exception MBeanException if the initializer of an object
     *  throws an exception
     * @exception ReflectionException if a Java reflection exception
     *  occurs when invoking the getter
     */
    public void setAttribute(Attribute attribute)
        throws AttributeNotFoundException, MBeanException,
        ReflectionException
    {
        if( log.isDebugEnabled() )
            log.debug("Setting attribute " + this + " " + attribute );

        if( (resource instanceof DynamicMBean) && 
             ! ( resource instanceof BaseModelMBean )) {
            try {
                ((DynamicMBean)resource).setAttribute(attribute);
            } catch (InvalidAttributeValueException e) {
                throw new MBeanException(e);                
            }
            return;
        }
        
        // Validate the input parameters
        if (attribute == null)
            throw new RuntimeOperationsException