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Commons Modeler example source code file (BaseModelMBean.java)

This example Commons Modeler source code file (BaseModelMBean.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons Modeler tags/keywords

attribute, cannot, class, error, exception, illegalargumentexception, management, mbeanexception, mbeanexception, object, object, reflection, runtimeoperationsexception, runtimeoperationsexception, string, string, util

The Commons Modeler BaseModelMBean.java source code

/*
 * 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.commons.modeler;


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

import javax.management.Attribute;
import javax.management.AttributeChangeNotification;
import javax.management.AttributeList;
import javax.management.AttributeNotFoundException;
import javax.management.Descriptor;
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.ServiceNotFoundException;
import javax.management.modelmbean.DescriptorSupport;
import javax.management.modelmbean.InvalidTargetObjectTypeException;
import javax.management.modelmbean.ModelMBean;
import javax.management.modelmbean.ModelMBeanAttributeInfo;
import javax.management.modelmbean.ModelMBeanInfo;
import javax.management.modelmbean.ModelMBeanInfoSupport;
import javax.management.modelmbean.ModelMBeanNotificationInfo;
import javax.management.modelmbean.ModelMBeanOperationInfo;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.commons.modeler.modules.ModelerSource;

// TODO: enable ant-like substitutions ? ( or at least discuss it )

/**
 * <p>Basic implementation of the ModelMBean 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. The String parameter
 * passed to the constructor will be used to construct an instance of the
 * real object that we wrap.
 *
 * Limitations:
 * <ul>
 * <li>Only managed resources of type objectReference are
 *     supportd.</li>
 * <li>Caching of attribute values and operation results is not supported.
 *     All calls to <code>invoke() are immediately executed.
 * <li>Logging (under control of descriptors) is not supported.
 * <li>Persistence of MBean attributes and operations is not supported.
 * <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.
 *     </ul>
 * <li>Attribute caching is not supported
 * </ul>
 *
 * @author Craig R. McClanahan
 * @author Costin Manolache
 * @version $Revision: 480402 $ $Date: 2006-11-29 04:43:23 +0000 (Wed, 29 Nov 2006) $
 */

public class BaseModelMBean implements ModelMBean, MBeanRegistration {
    private static Log log = LogFactory.getLog(BaseModelMBean.class);

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

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

        super();
        if( log.isDebugEnabled()) log.debug("default constructor");
        setModelMBeanInfo(createDefaultModelMBeanInfo());
    }


    /**
     * Construct a <code>ModelMBean associated with the specified
     * <code>ModelMBeanInfo information.
     *
     * @param info ModelMBeanInfo for this MBean
     *
     * @exception MBeanException if the initializer of an object
     *  throws an exception
     * @exception RuntimeOperationsException if an IllegalArgumentException
     *  occurs
     */
    public BaseModelMBean(ModelMBeanInfo info)
        throws MBeanException, RuntimeOperationsException {
        // XXX should be deprecated - just call setInfo
        super();
        setModelMBeanInfo(info);
        if( log.isDebugEnabled()) log.debug("ModelMBeanInfo constructor");
    }

    /** Construct a ModelMBean of a specified type.
     *  The type can be a class name or the key used in one of the descriptors.
     *
     * If no descriptor is available, we'll first try to locate one in
     * the same package with the class, then use introspection.
     *
     * The mbean resource will be created.
     *
     * @param type Class name or the type key used in the descriptor.
     * @throws MBeanException
     * @throws RuntimeOperationsException
     */
    public BaseModelMBean( String type )
        throws MBeanException, RuntimeOperationsException
    {
        try {
            // This constructor is used from <mlet>, it should create
            // the resource
            setModeledType(type);
        } catch( Throwable ex ) {
            log.error( "Error creating mbean ", ex);
        }
    }

    public BaseModelMBean( String type, ModelerSource source )
        throws MBeanException, RuntimeOperationsException
    {
        try {
            setModeledType(type);
        } catch( Throwable ex ) {
            log.error( "Error creating mbean ", ex);
        }
        this.source=source;
    }

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


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

    /** Registry we are associated with
     */
    protected Registry registry=null;

    /**
     * Notification broadcaster for general notifications.
     */
    protected BaseNotificationBroadcaster generalBroadcaster = null;

    protected ObjectName oname=null;

    /**
     * The <code>ModelMBeanInfo object that controls our activity.
     */
    protected ModelMBeanInfo info = null;


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

    /** Source object used to read this mbean. Can be used to
     * persist the mbean
     */
    protected ModelerSource source=null;

    /** Attribute values. XXX That can be stored in the value Field
     */
    protected HashMap attributes=new HashMap();

    // --------------------------------------------------- DynamicMBean Methods
    static final Object[] NO_ARGS_PARAM=new Object[0];
    static final Class[] NO_ARGS_PARAM_SIG=new Class[0];
    // key: attribute val: getter method
    private Hashtable getAttMap=new Hashtable();

    // key: attribute val: setter method
    private Hashtable setAttMap=new Hashtable();

    // 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);
        }
        
        // Extract the method from cache
        Method m=(Method)getAttMap.get( name );

        if( m==null ) {
            // Look up the actual operation to be used
            ModelMBeanAttributeInfo attrInfo = info.getAttribute(name);
            if (attrInfo == null)
                throw new AttributeNotFoundException(" Cannot find attribute " + name);
            Descriptor attrDesc = attrInfo.getDescriptor();
            if (attrDesc == null)
                throw new AttributeNotFoundException("Cannot find attribute " + name + " descriptor");
            String getMethod = (String) attrDesc.getFieldValue("getMethod");

            if (getMethod == null)
                throw new AttributeNotFoundException("Cannot find attribute " + name + " get method name");

            Object object = null;
            NoSuchMethodException exception = null;
            try {
                object = this;
                m = object.getClass().getMethod(getMethod, NO_ARGS_PARAM_SIG);
            } catch (NoSuchMethodException e) {
                exception = e;;
            }
            if( m== null && resource != null ) {
                try {
                    object = resource;
                    m = object.getClass().getMethod(getMethod, NO_ARGS_PARAM_SIG);
                    exception=null;
                } catch (NoSuchMethodException e) {
                    exception = e;
                }
            }
            if( exception != null )
                throw new ReflectionException(exception,
                                              "Cannot find getter method " + getMethod);
            getAttMap.put( name, m );
        }

        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);

    }


    /**
     * Return the <code>MBeanInfo object for this MBean.
     */
    public MBeanInfo getMBeanInfo() {
        // XXX Why do we have to clone ?
        if( info== null ) return null;
        return ((MBeanInfo) info.clone());
    }


    /**
     * Invoke a particular method on this MBean, and return any returned
     * value.
     *
     * <p>IMPLEMENTATION NOTE - 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=(Method)invokeAttMap.get(mkey);
        if( method==null ) {
            if (params == null)
                params = new Object[0];
            if (signature == null)
                signature = new String[0];
            if (params.length != signature.length)
                throw new RuntimeOperationsException
                    (new IllegalArgumentException("Inconsistent arguments and signature"),
                     "Inconsistent arguments and signature");

            // Acquire the ModelMBeanOperationInfo information for
            // the requested operation
            ModelMBeanOperationInfo opInfo = info.getOperation(name);
            if (opInfo == null)
                throw new MBeanException
                    (new ServiceNotFoundException("Cannot find operation " + name),
                     "Cannot find operation " + name);

            // Prepare the signature required by Java reflection APIs
            // FIXME - should we use the signature from opInfo?
            Class types[] = new Class[signature.length];
            for (int i = 0; i < signature.length; i++) {
                types[i]=getAttributeClass( signature[i] );
            }

            // Locate the method to be invoked, either in this MBean itself
            // or in the corresponding managed resource
            // FIXME - Accessible methods in superinterfaces?
            Object object = null;
            Exception exception = null;
            try {
                object = this;
                method = object.getClass().getMethod(name, types);
            } catch (NoSuchMethodException e) {
                exception = e;;
            }
            try {
                if ((method == null) && (resource != null)) {
                    object = resource;
                    method = object.getClass().getMethod(name, types);
                }
            } catch (NoSuchMethodException e) {
                exception = e;
            }
            if (method == null) {
                throw new ReflectionException(exception,
                                              "Cannot find method " + name +
                                              " with this signature");
            }
            invokeAttMap.put( mkey, method );
        }

        // 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);

    }

    private 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
                (new IllegalArgumentException("Attribute is null"),
                 "Attribute is null");

        String name = attribute.getName();
        Object value = attribute.getValue();

        if (name == null)
            throw new RuntimeOperationsException
                (new IllegalArgumentException("Attribute name is null"),
                 "Attribute name is null");

        ModelMBeanAttributeInfo attrInfo=info.getAttribute(name);
        if (attrInfo == null)
            throw new AttributeNotFoundException("Cannot find attribute " + name);

        Descriptor attrDesc=attrInfo.getDescriptor();
        if (attrDesc == null)
            throw new AttributeNotFoundException("Cannot find attribute " + name + " descriptor");

        Object oldValue=null;
        if( getAttMap.get(name) != null )
            oldValue=getAttribute( name );


        // Extract the method from cache
        Method m=(Method)setAttMap.get( name );

        if( m==null ) {
            // Look up the actual operation to be used
            String setMethod = (String) attrDesc.getFieldValue("setMethod");
            if (setMethod == null)
                throw new AttributeNotFoundException("Cannot find attribute " + name + " set method name");

            String argType=attrInfo.getType();

            Class signature[] = new Class[] { getAttributeClass( argType ) };

            Object object = null;
            NoSuchMethodException exception = null;
            try {
                object = this;
                m = object.getClass().getMethod(setMethod, signature);
            } catch (NoSuchMethodException e) {
                exception = e;;
            }
            if( m== null && resource != null ) {
                try {
                    object = resource;
                    m = object.getClass().getMethod(setMethod, signature);
                    exception=null;
                } catch (NoSuchMethodException e) {
                    if( log.isDebugEnabled())
                        log.debug("Method not found in resource " +resource);
                    exception = e;
                }
            }
            if( exception != null )
                throw new ReflectionException(exception,
                                              "Cannot find setter method " + setMethod +
                        " " + resource);
            setAttMap.put( name, m );
        }

        Object result = null;
        try {
            if( m.getDeclaringClass().isAssignableFrom( this.getClass()) ) {
                result = m.invoke(this, new Object[] { value });
            } else {
                result = m.invoke(resource, new Object[] { value });
            }
        } 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) {
            log.error("Exception invoking method " + name , e );
            throw new MBeanException
                (e, "Exception invoking method " + name);
        }
        try {
            sendAttributeChangeNotification(new Attribute( name, oldValue),
                    attribute);
        } catch(Exception ex) {
            log.error("Error sending notification " + name, ex);
        }
        attributes.put( name, value );
        if( source != null ) {
            // this mbean is asscoiated with a source - maybe we want to persist
            source.updateField(oname, name, value);
        }
    }

    public String toString() {
        if( resource==null ) 
            return "BaseModelMbean[" + resourceType + "]";
        return resource.toString();
    }

    /**
     * Set the values of several attributes of this MBean.
     *
     * @param attributes THe names and values to be set
     *
     * @return The list of attributes that were set and their new values
     */
    public AttributeList setAttributes(AttributeList attributes) {

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

        // Prepare and return our response, eating all exceptions
        AttributeList response = new AttributeList();
        String names[] = new String[attributes.size()];
        int n = 0;
        Iterator items = attributes.iterator();
        while (items.hasNext()) {
            Attribute item = (Attribute) items.next();
            names[n++] = item.getName();
            try {
                setAttribute(item);
            } catch (Exception e) {
                ; // Ignore all exceptions
            }
        }

        return (getAttributes(names));

    }


    // ----------------------------------------------------- ModelMBean Methods


    /**
     * Get the instance handle of the object against which we execute
     * all methods in this ModelMBean management interface.
     *
     * @exception InstanceNotFoundException if the managed resource object
     *  cannot be found
     * @exception MBeanException if the initializer of the object throws
     *  an exception
     * @exception RuntimeOperationsException if the managed resource or the
     *  resource type is <code>null or invalid
     */
    public Object getManagedResource()
        throws InstanceNotFoundException, InvalidTargetObjectTypeException,
        MBeanException, RuntimeOperationsException {

        if (resource == null)
            throw new RuntimeOperationsException
                (new IllegalArgumentException("Managed resource is null"),
                 "Managed resource is null");

        return resource;

    }


    /**
     * Set the instance handle of the object against which we will execute
     * all methods in this ModelMBean management interface.
     *
     * This method will detect and call "setModelMbean" method. A resource
     * can implement this method to get a reference to the model mbean.
     * The reference can be used to send notification and access the
     * registry.
     *
     * @param resource The resource object to be managed
     * @param type The type of reference for the managed resource
     *  ("ObjectReference", "Handle", "IOR", "EJBHandle", or
     *  "RMIReference")
     *
     * @exception InstanceNotFoundException if the managed resource object
     *  cannot be found
     * @exception InvalidTargetObjectTypeException if this ModelMBean is
     *  asked to handle a reference type it cannot deal with
     * @exception MBeanException if the initializer of the object throws
     *  an exception
     * @exception RuntimeOperationsException if the managed resource or the
     *  resource type is <code>null or invalid
     */
    public void setManagedResource(Object resource, String type)
        throws InstanceNotFoundException, InvalidTargetObjectTypeException,
        MBeanException, RuntimeOperationsException
    {
        if (resource == null)
            throw new RuntimeOperationsException
                (new IllegalArgumentException("Managed resource is null"),
                 "Managed resource is null");

        if (!"objectreference".equalsIgnoreCase(type))
            throw new InvalidTargetObjectTypeException(type);

        this.resource = resource;
        this.resourceType = resource.getClass().getName();
        
        // Make the resource aware of the model mbean.
        try {
            Method m=resource.getClass().getMethod("setModelMBean",
                    new Class[] {ModelMBean.class});
            if( m!= null ) {
                m.invoke(resource, new Object[] {this});
            }
        } catch( NoSuchMethodException t ) {
            // ignore
        } catch( Throwable t ) {
            log.error( "Can't set model mbean ", t );
        }
    }


    /**
     * Initialize the <code>ModelMBeanInfo associated with this
     * <code>ModelMBean.  After the information and associated
     * descriptors have been customized, the <code>ModelMBean should
     * be registered with the associated <code>MBeanServer.
     *
     * Currently the model can be set after registration. This behavior is
     * deprecated and won't be supported in future versions.
     *
     * @param info The ModelMBeanInfo object to be used by this ModelMBean
     *
     * @exception MBeanException If an exception occurs recording this
     *  ModelMBeanInfo information
     * @exception RuntimeOperations if the specified parameter is
     *  <code>null or invalid
     */
    public void setModelMBeanInfo(ModelMBeanInfo info)
        throws MBeanException, RuntimeOperationsException {

        if (info == null)
            throw new RuntimeOperationsException
                (new IllegalArgumentException("ModelMBeanInfo is null"),
                 "ModelMBeanInfo is null");

        if (!isModelMBeanInfoValid(info))
            throw new RuntimeOperationsException
                (new IllegalArgumentException("ModelMBeanInfo is invalid"),
                 "ModelMBeanInfo is invalid");

        this.info = (ModelMBeanInfo) info.clone();

    }


    // ------------------------------ ModelMBeanNotificationBroadcaster Methods


    /**
     * Add an attribute change notification event listener to this MBean.
     *
     * @param listener Listener that will receive event notifications
     * @param name Name of the attribute of interest, or <code>null
     *  to indicate interest in all attributes
     * @param handback Handback object to be sent along with event
     *  notifications
     *
     * @exception IllegalArgumentException if the listener parameter is null
     */
    public void addAttributeChangeNotificationListener
        (NotificationListener listener, String name, Object handback)
        throws IllegalArgumentException {

        if (listener == null)
            throw new IllegalArgumentException("Listener is null");
        if (attributeBroadcaster == null)
            attributeBroadcaster = new BaseNotificationBroadcaster();

        if( log.isDebugEnabled() )
            log.debug("addAttributeNotificationListener " + listener);

        BaseAttributeFilter filter = new BaseAttributeFilter(name);
        attributeBroadcaster.addNotificationListener
            (listener, filter, handback);

    }


    /**
     * Remove an attribute change notification event listener from
     * this MBean.
     *
     * @param listener The listener to be removed
     * @param name The attribute name for which no more events are required
     *
     *
     * @exception ListenerNotFoundException if this listener is not
     *  registered in the MBean
     */
    public void removeAttributeChangeNotificationListener
        (NotificationListener listener, String name)
        throws ListenerNotFoundException {

        if (listener == null)
            throw new IllegalArgumentException("Listener is null");
        if (attributeBroadcaster == null)
            attributeBroadcaster = new BaseNotificationBroadcaster();

        // FIXME - currently this removes *all* notifications for this listener
        attributeBroadcaster.removeNotificationListener(listener);

    }


    /**
     * Remove an attribute change notification event listener from
     * this MBean.
     *
     * @param listener The listener to be removed
     * @param attributeName The attribute name for which no more events are required
     * @param handback Handback object to be sent along with event
     *  notifications
     *
     *
     * @exception ListenerNotFoundException if this listener is not
     *  registered in the MBean
     */
    public void removeAttributeChangeNotificationListener
        (NotificationListener listener, String attributeName, Object handback)
        throws ListenerNotFoundException {

        removeAttributeChangeNotificationListener(listener, attributeName);

    }


    /**
     * Send an <code>AttributeChangeNotification to all registered
     * listeners.
     *
     * @param notification The <code>AttributeChangeNotification
     *  that will be passed
     *
     * @exception MBeanException if an object initializer throws an
     *  exception
     * @exception RuntimeOperationsException wraps IllegalArgumentException
     *  when the specified notification is <code>null or invalid
     */
    public void sendAttributeChangeNotification
        (AttributeChangeNotification notification)
        throws MBeanException, RuntimeOperationsException {

        if (notification == null)
            throw new RuntimeOperationsException
                (new IllegalArgumentException("Notification is null"),
                 "Notification is null");
        if (attributeBroadcaster == null)
            return; // This means there are no registered listeners
        if( log.isDebugEnabled() )
            log.debug( "AttributeChangeNotification " + notification );
        attributeBroadcaster.sendNotification(notification);

    }


    /**
     * Send an <code>AttributeChangeNotification to all registered
     * listeners.
     *
     * @param oldValue The original value of the <code>Attribute
     * @param newValue The new value of the <code>Attribute
     *
     * @exception MBeanException if an object initializer throws an
     *  exception
     * @exception RuntimeOperationsException wraps IllegalArgumentException
     *  when the specified notification is <code>null or invalid
     */
    public void sendAttributeChangeNotification
        (Attribute oldValue, Attribute newValue)
        throws MBeanException, RuntimeOperationsException {

        // Calculate the class name for the change notification
        String type = null;
        if (newValue.getValue() != null)
            type = newValue.getValue().getClass().getName();
        else if (oldValue.getValue() != null)
            type = oldValue.getValue().getClass().getName();
        else
            return;  // Old and new are both null == no change

        AttributeChangeNotification notification =
            new AttributeChangeNotification
            (this, 1, System.currentTimeMillis(),
             "Attribute value has changed",
             oldValue.getName(), type,
             oldValue.getValue(), newValue.getValue());
        sendAttributeChangeNotification(notification);

    }




    /**
     * Send a <code>Notification to all registered listeners as a
     * <code>jmx.modelmbean.general notification.
     *
     * @param notification The <code>Notification that will be passed
     *
     * @exception MBeanException if an object initializer throws an
     *  exception
     * @exception RuntimeOperationsException wraps IllegalArgumentException
     *  when the specified notification is <code>null or invalid
     */
    public void sendNotification(Notification notification)
        throws MBeanException, RuntimeOperationsException {

        if (notification == null)
            throw new RuntimeOperationsException
                (new IllegalArgumentException("Notification is null"),
                 "Notification is null");
        if (generalBroadcaster == null)
            return; // This means there are no registered listeners
        generalBroadcaster.sendNotification(notification);

    }


    /**
     * Send a <code>Notification which contains the specified string
     * as a <code>jmx.modelmbean.generic notification.
     *
     * @param message The message string to be passed
     *
     * @exception MBeanException if an object initializer throws an
     *  exception
     * @exception RuntimeOperationsException wraps IllegalArgumentException
     *  when the specified notification is <code>null or invalid
     */
    public void sendNotification(String message)
        throws MBeanException, RuntimeOperationsException {

        if (message == null)
            throw new RuntimeOperationsException
                (new IllegalArgumentException("Message is null"),
                 "Message is null");
        Notification notification = new Notification
            ("jmx.modelmbean.generic", this, 1, message);
        sendNotification(notification);

    }




    // ---------------------------------------- NotificationBroadcaster Methods


    /**
     * Add a notification event listener to this MBean.
     *
     * @param listener Listener that will receive event notifications
     * @param filter Filter object used to filter event notifications
     *  actually delivered, or <code>null for no filtering
     * @param handback Handback object to be sent along with event
     *  notifications
     *
     * @exception IllegalArgumentException if the listener parameter is null
     */
    public void addNotificationListener(NotificationListener listener,
                                        NotificationFilter filter,
                                        Object handback)
        throws IllegalArgumentException {

        if (listener == null)
            throw new IllegalArgumentException("Listener is null");

        if( log.isDebugEnabled() ) log.debug("addNotificationListener " + listener);

        if (generalBroadcaster == null)
            generalBroadcaster = new BaseNotificationBroadcaster();
        generalBroadcaster.addNotificationListener
            (listener, filter, handback);

        // We'll send the attribute change notifications to all listeners ( who care )
        // The normal filtering can be used.
        // The problem is that there is no other way to add attribute change listeners
        // to a model mbean ( AFAIK ). I suppose the spec should be fixed.
        if (attributeBroadcaster == null)
            attributeBroadcaster = new BaseNotificationBroadcaster();

        if( log.isDebugEnabled() )
            log.debug("addAttributeNotificationListener " + listener);

        attributeBroadcaster.addNotificationListener
                (listener, filter, handback);
    }


    /**
     * Return an <code>MBeanNotificationInfo object describing the
     * notifications sent by this MBean.
     */
    public MBeanNotificationInfo[] getNotificationInfo() {

        // Acquire the set of application notifications
        MBeanNotificationInfo current[] = info.getNotifications();
        if (current == null)
            current = new MBeanNotificationInfo[0];
        MBeanNotificationInfo response[] =
            new MBeanNotificationInfo[current.length + 2];
        Descriptor descriptor = null;

        // Fill in entry for general notifications
        descriptor = new DescriptorSupport
            (new String[] { "name=GENERIC",
                            "descriptorType=notification",
                            "log=T",
                            "severity=5",
                            "displayName=jmx.modelmbean.generic" });
        response[0] = new ModelMBeanNotificationInfo
            (new String[] { "jmx.modelmbean.generic" },
             "GENERIC",
             "Text message notification from the managed resource",
             descriptor);

        // Fill in entry for attribute change notifications
        descriptor = new DescriptorSupport
            (new String[] { "name=ATTRIBUTE_CHANGE",
                            "descriptorType=notification",
                            "log=T",
                            "severity=5",
                            "displayName=jmx.attribute.change" });
        response[1] = new ModelMBeanNotificationInfo
            (new String[] { "jmx.attribute.change" },
             "ATTRIBUTE_CHANGE",
             "Observed MBean attribute value has changed",
             descriptor);

        // Copy remaining notifications as reported by the application
        System.arraycopy(current, 0, response, 2, current.length);
        return (response);

    }


    /**
     * Remove a notification event listener from this MBean.
     *
     * @param listener The listener to be removed (any and all registrations
     *  for this listener will be eliminated)
     *
     * @exception ListenerNotFoundException if this listener is not
     *  registered in the MBean
     */
    public void removeNotificationListener(NotificationListener listener)
        throws ListenerNotFoundException {

        if (listener == null)
            throw new IllegalArgumentException("Listener is null");
        if (generalBroadcaster == null)
            generalBroadcaster = new BaseNotificationBroadcaster();
        generalBroadcaster.removeNotificationListener(listener);


    }


    /**
     * Remove a notification event listener from this MBean.
     *
     * @param listener The listener to be removed (any and all registrations
     *  for this listener will be eliminated)
     * @param handback Handback object to be sent along with event
     *  notifications
     *
     * @exception ListenerNotFoundException if this listener is not
     *  registered in the MBean
     */
    public void removeNotificationListener(NotificationListener listener,
                                           Object handback)
        throws ListenerNotFoundException {

        removeNotificationListener(listener);

    }


    /**
     * Remove a notification event listener from this MBean.
     *
     * @param listener The listener to be removed (any and all registrations
     *  for this listener will be eliminated)
     * @param filter Filter object used to filter event notifications
     *  actually delivered, or <code>null for no filtering
     * @param handback Handback object to be sent along with event
     *  notifications
     *
     * @exception ListenerNotFoundException if this listener is not
     *  registered in the MBean
     */
    public void removeNotificationListener(NotificationListener listener,
                                           NotificationFilter filter,
                                           Object handback)
        throws ListenerNotFoundException {

        removeNotificationListener(listener);

    }


    // ------------------------------------------------ PersistentMBean Methods


    /**
     * Instantiates this MBean instance from data found in the persistent
     * store.  The data loaded could include attribute and operation values.
     * This method should be called during construction or initialization
     * of the instance, and before the MBean is registered with the
     * <code>MBeanServer.
     *
     * <p>IMPLEMENTATION NOTE - This implementation does
     * not support persistence.</p>
     *
     * @exception InstanceNotFoundException if the managed resource object
     *  cannot be found
     * @exception MBeanException if the initializer of the object throws
     *  an exception
     * @exception RuntimeOperationsException if an exception is reported
     *  by the persistence mechanism
     */
    public void load() throws InstanceNotFoundException,
        MBeanException, RuntimeOperationsException {
        // XXX If a context was set, use it to load the data
        throw new MBeanException
            (new IllegalStateException("Persistence is not supported"),
             "Persistence is not supported");

    }


    /**
     * Capture the current state of this MBean instance and write it out
     * to the persistent store.  The state stored could include attribute
     * and operation values.  If one of these methods of persistence is not
     * supported, a "service not found" exception will be thrown.
     *
     * <p>IMPLEMENTATION NOTE - This implementation does
     * not support persistence.</p>
     *
     * @exception InstanceNotFoundException if the managed resource object
     *  cannot be found
     * @exception MBeanException if the initializer of the object throws
     *  an exception, or persistence is not supported
     * @exception RuntimeOperationsException if an exception is reported
     *  by the persistence mechanism
     */
    public void store() throws InstanceNotFoundException,
        MBeanException, RuntimeOperationsException {

        // XXX if a context was set, use it to store the data
        throw new MBeanException
            (new IllegalStateException("Persistence is not supported"),
             "Persistence is not supported");

    }

    // --------------------  BaseModelMBean methods --------------------

    /** Set the type of the mbean. This is used as a key to locate
     * the description in the Registry.
     *
     * @param type the type of classname of the modeled object
     */
    public void setModeledType( String type ) {
        initModelInfo(type);
        createResource();
    }
    /** Set the type of the mbean. This is used as a key to locate
     * the description in the Registry.
     *
     * @param type the type of classname of the modeled object
     */
    protected void initModelInfo( String type ) {
        try {
            if( log.isDebugEnabled())
                log.debug("setModeledType " + type);

            log.debug( "Set model Info " + type);
            if(type==null) {
                return;
            }
            resourceType=type;
            //Thread.currentThread().setContextClassLoader(BaseModelMBean.class.getClassLoader());
            Class c=null;
            try {
                c=Class.forName( type);
            } catch( Throwable t ) {
                log.debug( "Error creating class " + t);
            }

            // The class c doesn't need to exist
            ManagedBean descriptor=getRegistry().findManagedBean(c, type);
            if( descriptor==null ) 
                return;
            this.setModelMBeanInfo(descriptor.createMBeanInfo());
        } catch( Throwable ex) {
            log.error( "TCL: " + Thread.currentThread().getContextClassLoader(),
                    ex);
        }
    }

    /** Set the type of the mbean. This is used as a key to locate
     * the description in the Registry.
     */
    protected void createResource() {
        try {
            //Thread.currentThread().setContextClassLoader(BaseModelMBean.class.getClassLoader());
            Class c=null;
            try {
                c=Class.forName( resourceType );
                resource = c.newInstance();
            } catch( Throwable t ) {
                log.error( "Error creating class " + t);
            }
        } catch( Throwable ex) {
            log.error( "TCL: " + Thread.currentThread().getContextClassLoader(),
                    ex);
        }
    }


    public String getModelerType() {
        return resourceType;
    }

    public String getClassName() {
        return getModelerType();
    }

    public ObjectName getJmxName() {
        return oname;
    }

    public String getObjectName() {
        if (oname != null) {
            return oname.toString();
        } else {
            return null;
        }
    }

    public void setRegistry(Registry registry) {
        this.registry = registry;
    }

    public Registry getRegistry() {
        // XXX Need a better solution - to avoid the static
        if( registry == null )
            registry=Registry.getRegistry();

        return registry;
    }

    // ------------------------------------------------------ Protected Methods


    /**
     * Create and return a default <code>ModelMBeanInfo object.
     */
    protected ModelMBeanInfo createDefaultModelMBeanInfo() {

        return (new ModelMBeanInfoSupport(this.getClass().getName(),
                                          "Default ModelMBean",
                                          null, null, null, null));

    }

    /**
     * Is the specified <code>ModelMBeanInfo instance valid?
     *
     * <p>IMPLEMENTATION NOTE - This implementation
     * does not check anything, but this method can be overridden
     * as required.</p>
     *
     * @param info The <code>ModelMBeanInfo object to check
     */
    protected boolean isModelMBeanInfoValid(ModelMBeanInfo info) {
        return (true);
    }

    // -------------------- Registration  --------------------
    // XXX We can add some method patterns here- like setName() and
    // setDomain() for code that doesn't implement the Registration

    public ObjectName preRegister(MBeanServer server,
                                  ObjectName name)
            throws Exception
    {
        if( log.isDebugEnabled())
            log.debug("preRegister " + resource + " " + name );
        oname=name;
        if( resource instanceof MBeanRegistration ) {
            oname = ((MBeanRegistration)resource).preRegister(server, name );
        }
        return oname;
    }

    public void postRegister(Boolean registrationDone) {
        if( resource instanceof MBeanRegistration ) {
            ((MBeanRegistration)resource).postRegister(registrationDone);
        }
    }

    public void preDeregister() throws Exception {
        if( resource instanceof MBeanRegistration ) {
            ((MBeanRegistration)resource).preDeregister();
        }
    }

    public void postDeregister() {
        if( resource instanceof MBeanRegistration ) {
            ((MBeanRegistration)resource).postDeregister();
        }
    }

    static class MethodKey {
	private String name;
	private String[] signature;

	MethodKey(String name, String[] signature) {
	    this.name = name;
	    if(signature == null) {
		signature = new String[0];
	    }
	    this.signature = signature;
	}

	public boolean equals(Object other) {
	    if(!(other instanceof MethodKey)) {
		return false;
	    }
	    MethodKey omk = (MethodKey)other;
	    if(!name.equals(omk.name)) {
		return false;
	    }
	    if(signature.length != omk.signature.length) {
		return false;
	    }
	    for(int i=0; i < signature.length; i++) {
		if(!signature[i].equals(omk.signature[i])) {
		    return false;
		}
	    }
	    return true;
	}

	public int hashCode() {
	    return name.hashCode();
	}
    }
}

Other Commons Modeler examples (source code examples)

Here is a short list of links related to this Commons Modeler BaseModelMBean.java source code file:

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