Tomcat example source code file (ManagedBean.java)

This example Tomcat source code file (ManagedBean.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 - Tomcat tags/keywords

attributeinfo, attributenotfoundexception, basemodelmbean, cannot, cannot, management, mbeanexception, method, nosuchmethodexception, nosuchmethodexception, object, object, reflection, reflectionexception, string, string, util

The Tomcat ManagedBean.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.tomcat.util.modeler;


import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;

import javax.management.AttributeNotFoundException;
import javax.management.DynamicMBean;
import javax.management.InstanceNotFoundException;
import javax.management.MBeanAttributeInfo;
import javax.management.MBeanConstructorInfo;
import javax.management.MBeanException;
import javax.management.MBeanInfo;
import javax.management.MBeanNotificationInfo;
import javax.management.MBeanOperationInfo;
import javax.management.ReflectionException;
import javax.management.RuntimeOperationsException;
import javax.management.ServiceNotFoundException;
//import javax.management.modelmbean.InvalidTargetObjectTypeException;


/**
 * <p>Internal configuration information for a managed bean (MBean)
 * descriptor.</p>
 *
 * @author Craig R. McClanahan
 * @version $Revision: 610929 $ $Date: 2008-01-10 22:04:31 +0100 (jeu., 10 janv. 2008) $
 */

public class ManagedBean implements java.io.Serializable
{
    private static final String BASE_MBEAN = "org.apache.tomcat.util.modeler.BaseModelMBean";
    // ----------------------------------------------------- Instance Variables
    static final Object[] NO_ARGS_PARAM=new Object[0];
    static final Class[] NO_ARGS_PARAM_SIG=new Class[0];


    /**
     * The <code>ModelMBeanInfo object that corresponds
     * to this <code>ManagedBean instance.
     */
    transient MBeanInfo info = null;
    // Map<AttributeInfo>
    private Map attributes = new HashMap();
    //Map<OperationInfo>
    private Map operations = new HashMap();
    
    protected String className = BASE_MBEAN;
    //protected ConstructorInfo constructors[] = new ConstructorInfo[0];
    protected String description = null;
    protected String domain = null;
    protected String group = null;
    protected String name = null;

    //protected List fields = new ArrayList();
    protected NotificationInfo notifications[] = new NotificationInfo[0];
    protected String type = null;

    /** Constructor. Will add default attributes. 
     *  
     */ 
    public ManagedBean() {
        AttributeInfo ai=new AttributeInfo();
        ai.setName("modelerType");
        ai.setDescription("Type of the modeled resource. Can be set only once");
        ai.setType("java.lang.String");
        ai.setWriteable(false);
        addAttribute(ai);
    }
    
    // ------------------------------------------------------------- Properties


    /**
     * The collection of attributes for this MBean.
     */
    public AttributeInfo[] getAttributes() {
        AttributeInfo result[] = new AttributeInfo[attributes.size()];
        attributes.values().toArray(result);
        return result;
    }


    /**
     * The fully qualified name of the Java class of the MBean
     * described by this descriptor.  If not specified, the standard JMX
     * class (<code>javax.management.modelmbean.RequiredModeLMBean)
     * will be utilized.
     */
    public String getClassName() {
        return (this.className);
    }

    public void setClassName(String className) {
        this.className = className;
        this.info = null;
    }


//    /**
//     * The collection of constructors for this MBean.
//     */
//    public ConstructorInfo[] getConstructors() {
//        return (this.constructors);
//    }


    /**
     * The human-readable description of this MBean.
     */
    public String getDescription() {
        return (this.description);
    }

    public void setDescription(String description) {
        this.description = description;
        this.info = null;
    }


    /**
     * The (optional) <code>ObjectName domain in which this MBean
     * should be registered in the MBeanServer.
     */
    public String getDomain() {
        return (this.domain);
    }

    public void setDomain(String domain) {
        this.domain = domain;
    }


    /**
     * <p>Return a List of the {@link FieldInfo} objects for
     * the name/value pairs that should be
     * added to the Descriptor created from this metadata.</p>
     */
//    public List getFields() {
//        return (this.fields);
//    }
//

    /**
     * The (optional) group to which this MBean belongs.
     */
    public String getGroup() {
        return (this.group);
    }

    public void setGroup(String group) {
        this.group = group;
    }


    /**
     * The name of this managed bean, which must be unique among all
     * MBeans managed by a particular MBeans server.
     */
    public String getName() {
        return (this.name);
    }

    public void setName(String name) {
        this.name = name;
        this.info = null;
    }


    /**
     * The collection of notifications for this MBean.
     */
    public NotificationInfo[] getNotifications() {
        return (this.notifications);
    }


    /**
     * The collection of operations for this MBean.
     */
    public OperationInfo[] getOperations() {
        OperationInfo[] result = new OperationInfo[operations.size()];
        operations.values().toArray(result);
        return result;
    }


    /**
     * The fully qualified name of the Java class of the resource
     * implementation class described by the managed bean described
     * by this descriptor.
     */
    public String getType() {
        return (this.type);
    }

    public void setType(String type) {
        this.type = type;
        this.info = null;
    }


    // --------------------------------------------------------- Public Methods


    /**
     * Add a new attribute to the set of attributes for this MBean.
     *
     * @param attribute The new attribute descriptor
     */
    public void addAttribute(AttributeInfo attribute) {
        attributes.put(attribute.getName(), attribute);
    }


    /**
     * Add a new constructor to the set of constructors for this MBean.
     *
     * @param constructor The new constructor descriptor
     */
//    public void addConstructor(ConstructorInfo constructor) {
//
//        synchronized (constructors) {
//            ConstructorInfo results[] =
//                new ConstructorInfo[constructors.length + 1];
//            System.arraycopy(constructors, 0, results, 0, constructors.length);
//            results[constructors.length] = constructor;
//            constructors = results;
//            this.info = null;
//        }
//
//    }


    /**
     * <p>Add a new field to the fields associated with the
     * Descriptor that will be created from this metadata.</p>
     *
     * @param field The field to be added
     */
//    public void addField(FieldInfo field) {
//        fields.add(field);
//    }


    /**
     * Add a new notification to the set of notifications for this MBean.
     *
     * @param notification The new notification descriptor
     */
    public void addNotification(NotificationInfo notification) {

        synchronized (notifications) {
            NotificationInfo results[] =
                new NotificationInfo[notifications.length + 1];
            System.arraycopy(notifications, 0, results, 0,
                             notifications.length);
            results[notifications.length] = notification;
            notifications = results;
            this.info = null;
        }

    }


    /**
     * Add a new operation to the set of operations for this MBean.
     *
     * @param operation The new operation descriptor
     */
    public void addOperation(OperationInfo operation) {
        operations.put(operation.getName(), operation);
    }


    /**
     * Create and return a <code>ModelMBean that has been
     * preconfigured with the <code>ModelMBeanInfo information
     * for this managed bean, but is not associated with any particular
     * managed resource.  The returned <code>ModelMBean will
     * <strong>NOT have been registered with our
     * <code>MBeanServer.
     *
     * @exception InstanceNotFoundException if the managed resource
     *  object cannot be found
     * @exception InvalidTargetObjectTypeException if our MBean cannot
     *  handle object references (should never happen)
     * @exception MBeanException if a problem occurs instantiating the
     *  <code>ModelMBean instance
     * @exception RuntimeOperationsException if a JMX runtime error occurs
     */
    public DynamicMBean createMBean()
        throws InstanceNotFoundException,
        MBeanException, RuntimeOperationsException {

        return (createMBean(null));

    }


    /**
     * Create and return a <code>ModelMBean that has been
     * preconfigured with the <code>ModelMBeanInfo information
     * for this managed bean, and is associated with the specified
     * managed object instance.  The returned <code>ModelMBean
     * will <strong>NOT have been registered with our
     * <code>MBeanServer.
     *
     * @param instance Instanced of the managed object, or <code>null
     *  for no associated instance
     *
     * @exception InstanceNotFoundException if the managed resource
     *  object cannot be found
     * @exception InvalidTargetObjectTypeException if our MBean cannot
     *  handle object references (should never happen)
     * @exception MBeanException if a problem occurs instantiating the
     *  <code>ModelMBean instance
     * @exception RuntimeOperationsException if a JMX runtime error occurs
     */
    public DynamicMBean createMBean(Object instance)
        throws InstanceNotFoundException,
        MBeanException, RuntimeOperationsException {

        BaseModelMBean mbean = null;

        // Load the ModelMBean implementation class
        if(getClassName().equals(BASE_MBEAN)) {
            // Skip introspection
            mbean = new BaseModelMBean();
        } else {
            Class clazz = null;
            Exception ex = null;
            try {
                clazz = Class.forName(getClassName());
            } catch (Exception e) {
            }
          
            if( clazz==null ) {  
                try {
                    ClassLoader cl= Thread.currentThread().getContextClassLoader();
                    if ( cl != null)
                        clazz= cl.loadClass(getClassName());
                } catch (Exception e) {
                    ex=e;
                }
            }
    
            if( clazz==null) { 
                throw new MBeanException
                    (ex, "Cannot load ModelMBean class " + getClassName());
            }
            try {
                // Stupid - this will set the default minfo first....
                mbean = (BaseModelMBean) clazz.newInstance();
            } catch (RuntimeOperationsException e) {
                throw e;
            } catch (Exception e) {
                throw new MBeanException
                    (e, "Cannot instantiate ModelMBean of class " +
                     getClassName());
            }
        }
        
        mbean.setManagedBean(this);
        
        // Set the managed resource (if any)
        try {
            if (instance != null)
                mbean.setManagedResource(instance, "ObjectReference");
        } catch (InstanceNotFoundException e) {
            throw e;
        }
        return (mbean);

    }


    /**
     * Create and return a <code>ModelMBeanInfo object that
     * describes this entire managed bean.
     */
    MBeanInfo getMBeanInfo() {

        // Return our cached information (if any)
        if (info != null)
            return (info);

        // Create subordinate information descriptors as required
        AttributeInfo attrs[] = getAttributes();
        MBeanAttributeInfo attributes[] =
            new MBeanAttributeInfo[attrs.length];
        for (int i = 0; i < attrs.length; i++)
            attributes[i] = attrs[i].createAttributeInfo();

        OperationInfo opers[] = getOperations();
        MBeanOperationInfo operations[] =
            new MBeanOperationInfo[opers.length];
        for (int i = 0; i < opers.length; i++)
            operations[i] = opers[i].createOperationInfo();


//        ConstructorInfo consts[] = getConstructors();
//        ModelMBeanConstructorInfo constructors[] =
//            new ModelMBeanConstructorInfo[consts.length];
//        for (int i = 0; i < consts.length; i++)
//            constructors[i] = consts[i].createConstructorInfo();
        
        NotificationInfo notifs[] = getNotifications();
        MBeanNotificationInfo notifications[] =
            new MBeanNotificationInfo[notifs.length];
        for (int i = 0; i < notifs.length; i++)
            notifications[i] = notifs[i].createNotificationInfo();

        
        // Construct and return a new ModelMBeanInfo object
        info = new MBeanInfo(getClassName(), 
                             getDescription(),
                             attributes, 
                             new MBeanConstructorInfo[] {}, 
                             operations, 
                             notifications);
//        try {
//            Descriptor descriptor = info.getMBeanDescriptor();
//            Iterator fields = getFields().iterator();
//            while (fields.hasNext()) {
//                FieldInfo field = (FieldInfo) fields.next();
//                descriptor.setField(field.getName(), field.getValue());
//            }
//            info.setMBeanDescriptor(descriptor);
//        } catch (MBeanException e) {
//            ;
//        }

        return (info);

    }


    /**
     * Return a string representation of this managed bean.
     */
    public String toString() {

        StringBuffer sb = new StringBuffer("ManagedBean[");
        sb.append("name=");
        sb.append(name);
        sb.append(", className=");
        sb.append(className);
        sb.append(", description=");
        sb.append(description);
        if (group != null) {
            sb.append(", group=");
            sb.append(group);
        }
        sb.append(", type=");
        sb.append(type);
        sb.append("]");
        return (sb.toString());

    }

    Method getGetter(String aname, BaseModelMBean mbean, Object resource) 
            throws AttributeNotFoundException, MBeanException, ReflectionException {
        // TODO: do we need caching ? JMX is for management, it's not supposed to require lots of performance.
        Method m=null; // (Method)getAttMap.get( name );

        if( m==null ) {
            AttributeInfo attrInfo = (AttributeInfo)attributes.get(aname);
            // Look up the actual operation to be used
            if (attrInfo == null)
                throw new AttributeNotFoundException(" Cannot find attribute " + aname + " for " + resource);
            
            String getMethod = attrInfo.getGetMethod();
            if (getMethod == null)
                throw new AttributeNotFoundException("Cannot find attribute " + aname + " get method name");

            Object object = null;
            NoSuchMethodException exception = null;
            try {
                object = mbean;
                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 );
        }

        return m;
    }

    public Method getSetter(String aname, BaseModelMBean bean, Object resource) 
            throws AttributeNotFoundException, MBeanException, ReflectionException {
        // Cache may be needed for getters, but it is a really bad idea for setters, this is far 
        // less frequent.
        Method m=null;//(Method)setAttMap.get( name );

        if( m==null ) {
            AttributeInfo attrInfo = (AttributeInfo)attributes.get(aname);
            if (attrInfo == null)
                throw new AttributeNotFoundException(" Cannot find attribute " + aname);

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

            String argType=attrInfo.getType();

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

            Object object = null;
            NoSuchMethodException exception = null;
            try {
                object = bean;
                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) {
                    exception = e;
                }
            }
            if( exception != null )
                throw new ReflectionException(exception,
                                              "Cannot find setter method " + setMethod +
                        " " + resource);
            //setAttMap.put( name, m );
        }

        return m;
    }

    public Method getInvoke(String aname, Object[] params, String[] signature, BaseModelMBean bean, Object resource) 
            throws MBeanException, ReflectionException {
        Method method = null;
        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
            OperationInfo opInfo = (OperationInfo)operations.get(aname);
            if (opInfo == null)
                throw new MBeanException(new ServiceNotFoundException(
                        "Cannot find operation " + aname),
                        "Cannot find operation " + aname);

            // 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] = BaseModelMBean.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 = bean;
                method = object.getClass().getMethod(aname, types);
            } catch (NoSuchMethodException e) {
                exception = e;
                ;
            }
            try {
                if ((method == null) && (resource != null)) {
                    object = resource;
                    method = object.getClass().getMethod(aname, types);
                }
            } catch (NoSuchMethodException e) {
                exception = e;
            }
            if (method == null) {
                throw new ReflectionException(exception, "Cannot find method "
                        + aname + " with this signature");
            }
            // invokeAttMap.put(mkey, method);
        }
        return method;
    }


}