JMX--Dynamic MBean


直接或间接实现DynamicMBean接口的类就是Dynamic MBean，动态MBean中的属性和操作只在运行时暴露出来，所以动态MBean适合于管理非静态的信息。

优势：
1．不用定义你自己的接口
2．属性和操作只在运行期暴露，可被动态控制
3．可以提供对MBean和他的属性和操作的描述

DynamicMBean interface定义了如下6个方法：
getMBeanInfo
getAttribute
setAttribute
getAttributes
setAttributes
invoke

getMBeanInfo方法返回一个MBeanInfo 对象，其中包括了可以获得的信息 attributes operations constructors notification，管理信息通过MBeanInfo获得，这是强于Standard MBeans的优势之一，Standard MBeans中管理信息通过Standard MBeans内省方式得到，所以实现类必须遵循方法的标准命名规范，动态MBean就没有这个限制，如果实现类中定义了一个printName()方法，他没有遵循命名规范，但他仍可以成为某属性的getter or setter 方法。

getAttribute and setAttribute 取得/设置某属性。
getAttributes and setAttributes 取得/设置某些属性。

Invoke 可以触发某方法。

下面创建一个简单的动态mbean，然后用agent调用它。

//实现动态MBean接口
//

package jmx.test;

import java.lang.reflect.Constructor;
import java.util.Iterator;

import javax.management.Attribute;
import javax.management.AttributeList;
import javax.management.
    AttributeNotFoundException;
import javax.management.DynamicMBean;
import javax.management.
    InvalidAttributeValueException;
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.MBeanParameterInfo;
import javax.management.ReflectionException;
import javax.management.
    RuntimeOperationsException;

public class MyDynamic implements DynamicMBean{
//-----------------dynamic mbean part
private String className = 
    this.getClass().getName();
private String description = 
    "Simple implementation of a dynamic MBean.";
private MBeanInfo mBeanInfo = null;
private MBeanConstructorInfo[] constructorInfo=
    null;
private MBeanAttributeInfo[] attributeInfo = 
    null;
private MBeanOperationInfo[] operationInfo = 
    null;

public MyDynamic(){
	buildDynamicMBeanInfo();
}

public Object getAttribute(String attribute_name) 
	throws AttributeNotFoundException,
	       MBeanException,
	       ReflectionException {
	
    //attribute_name == null
    if(attribute_name == null){
	throw new RuntimeOperationsException(
	    new IllegalArgumentException(
	        "Attribute name cannot be null"), 
		"Cannot invoke a getter of " + 
		className + 
		" with null attribute name");
    }
    //attribute_name为"state"
    if(attribute_name.equals("state")){
	return getState();
    }
    //attribute_name为"num"
    else if(attribute_name.equals("num")){
	return new Integer(getNum());
    }
    //attribute_name不存在
    throw(new AttributeNotFoundException(
        "Cannot find " + attribute_name + 
	" attribute in " + className));
}

public void setAttribute(Attribute attribute) 
	throws AttributeNotFoundException,
	       InvalidAttributeValueException,
	       MBeanException, 
	       ReflectionException {
	
    //attribute == null
    if(attribute == null){
	throw new RuntimeOperationsException(
	    new IllegalArgumentException(
	        "Attribute cannot be null"), 
		"Cannot invoke a setter of " + 
		className + 
		" with null attribute");
    }
	
    String name = attribute.getName();
    Object value = attribute.getValue();

    //attribute.name = state
    if(name.equals("state")){
	//value == null
	if(value == null){
		setState(null);
	}
	//比较value与state的类型
	else{
	    try{
		if((value.getClass())
		    .isAssignableFrom(
		    Class.forName(
		        "java.lang.String"))){
		
		    setState((String)value);
		}else{
		  throw(new 
		  InvalidAttributeValueException(
		      "Cannot set attribute "+ 
		      name +" to a " + 
		      value.getClass().getName() 
		      + " object, " + 
		          "String expected"));
		}
	    }catch(Exception e){
		e.printStackTrace();
	    }
	}
    }
    //attribute.name = num
    else if(name.equals("num")){
      //value == null
      if(value == null){
	setNum(0);
      }
      //比较value与num的类型
      else{
	try{
	  if(value.getClass().isAssignableFrom(
	      Class.forName(
	      "java.lang.Integer"))){

	    setNum(((Integer)value).intValue());
	  }else{
	    throw(new 
	    InvalidAttributeValueException(
	    "Cannot set attribute "+ name +
	    " to a " + value.getClass().getName()
	    + " object, Integer expected"));
	}
	}catch(Exception e){
	  e.printStackTrace();
	}
      }
    }
//attribute.name不存在
else{
    throw(new AttributeNotFoundException(
    "Attribute " + name + " not found in " 
    + this.getClass().getName()));
}
}

public AttributeList getAttributes(
    String[] attributeNames) {
	
    //attributeNames == null
    if(attributeNames == null){
	throw new RuntimeOperationsException(
	  new IllegalArgumentException(
	  "attributeNames[] cannot be null"),
	  "Cannot invoke a getter of " 
	  + className);
    }

    AttributeList attributeList = 
        new AttributeList();
    //attributeNames.length = 0
    if(attributeNames.length == 0){
	return attributeList;
    }
    //遍历数组，进行设置
    for(int i=0; i<attributeNames.length; i++){
	try{
	  Object value = 
	    getAttribute(attributeNames<i>);
	  attributeList.add(new Attribute(
	    attributeNames<i>, value));
	}catch(Exception e){
		e.printStackTrace();
	}
    }
    return attributeList;
}

public AttributeList setAttributes(
    AttributeList attributes) {

    //attributes == null
    if(attributes == null){
      throw new RuntimeOperationsException(
      new IllegalArgumentException(
      "AttributeList attributes cannot be null"),
      "Cannot invoke a setter of " + className);
    }

    AttributeList attributeList = 
        new AttributeList();

    //attributes is empty
    if(attributes.isEmpty()){
	return attributeList;
    }

    //遍历，设置
    Iterator it = attributes.iterator();
    while(it.hasNext()){
	Attribute attribute = 
	    (Attribute)it.next();
	try{
	  setAttribute(attribute);
	  String name = attribute.getName();
	  Object value = attribute.getValue();
	  attributeList.add(
	      new Attribute(name, value));
	}catch(Exception e){
	  e.printStackTrace();
	}
    }

    return attributeList;
}

public Object invoke(String operationName, 
    Object params[], String signature[])
	throws MBeanException,
	       ReflectionException {
	
    //operationName == null
    if(operationName == null){
	throw new RuntimeOperationsException(
	new IllegalArgumentException(
	    "Operation name cannot be null"), 
	"Cannot invoke a null operation in " + 
	className);
    }
    //operationNam is "reset"
    if(operationName.equals("reset")){
	reset();
	return null;
    }
    //operationNam不存在
    else{
	throw new ReflectionException(
	new NoSuchMethodException(operationName), 
	  "Cannot find the operation " + 
	  operationName + " in " + className);
    }
}

public MBeanInfo getMBeanInfo() {
	return mBeanInfo;
}

private void buildDynamicMBeanInfo() {
    constructorInfo = new MBeanConstructorInfo[1];
    Constructor[] constructors = 
      this.getClass().getConstructors();
    constructorInfo[0] = 
      new MBeanConstructorInfo(
      "MyDynamic():Constructs a dynamic object",
      constructors[0]);

    //Attributes
    attributeInfo = new MBeanAttributeInfo[2];
    attributeInfo[0] = new MBeanAttributeInfo(
		"state",
		"java.lang.String",
		"state: state string",
		true,
		true,
		false);

    attributeInfo[1] = new MBeanAttributeInfo(
		"num",
		"java.lang.Integer",
		"num: number",
		true,
		true,
		false);

    //Operations
    operationInfo = new MBeanOperationInfo[1];
    MBeanParameterInfo[] params = null; 
    operationInfo[0] = new MBeanOperationInfo(
		"reset",
		"reset state and num",
		params,
		"void",
		MBeanOperationInfo.ACTION);

    mBeanInfo = new MBeanInfo(
		className,
		description,
		attributeInfo,
		constructorInfo,
		operationInfo,
		new MBeanNotificationInfo[0]);
}

//-------------------------------------self part
private String state = "initial state";
private int num = 0;

public int getNum() {
	return num;
}

public void setNum(int num) {
	this.num = num;
}

public String getState() {
	return state;
}

public void setState(String state) {
	this.state = state;
}

public void reset(){
	state = "initial state";
	num = 0;
}
}

//动态代理
//
//

package jmx.test;

import javax.management.Attribute;
import javax.management.MBeanAttributeInfo;
import javax.management.MBeanConstructorInfo;
import javax.management.MBeanInfo;
import javax.management.MBeanOperationInfo;
import javax.management.MBeanParameterInfo;
import javax.management.MBeanServer;
import javax.management.MBeanServerFactory;
import javax.management.
    MalformedObjectNameException;
import javax.management.ObjectName;

public class DynamicAgent {
private MBeanServer server = null;

public DynamicAgent(){
	server = MBeanServerFactory.
	    createMBeanServer();
}

public static void main(String[] args){
	
	DynamicAgent agent = new DynamicAgent();
	
	ObjectName mbeanObjectName = null;
	String mbeanName = 
	    "jmx.test.MyDynamic";
	String domain = agent.getServer().
	    getDefaultDomain();
	try {
	    mbeanObjectName = new ObjectName(
	        domain + ":type=" + mbeanName);
	} catch(MalformedObjectNameException e) {
	    e.printStackTrace();
	    System.exit(1);
	}
	agent.createSimpleBean(mbeanObjectName, 
	    mbeanName);
	agent.printMBeanInfo(mbeanObjectName, 
	    mbeanName);
	agent.manageSimpleBean(mbeanObjectName, 
	    mbeanName);
}
/**
 * 创建一个动态mbean
 * @param mbeanObjectName
 * @param mbeanName
 */
private void createSimpleBean(
  ObjectName mbeanObjectName, String mbeanName){

	String mbeanClassName = mbeanName;
	try {
	    server.createMBean(mbeanClassName,
	        mbeanObjectName);
	} catch(Exception e) {
	    e.printStackTrace();
	    System.exit(1);
	}
}
/**
 * 打印MBeanInfo信息
 * @param mbeanObjectName
 * @param mbeanName
 */
private void printMBeanInfo(
  ObjectName mbeanObjectName, String mbeanName) {
	MBeanInfo info = null;
	try {
	    info = server.getMBeanInfo(
	        mbeanObjectName);
	} catch (Exception e) {
	    e.printStackTrace();
	    return;
	}
	
	echo("----------------" + 
	    "Attribute info--------------");
	MBeanAttributeInfo[] attrInfo = 
	    info.getAttributes();
	if (attrInfo.length>0) {
	    for(int i=0; i<attrInfo.length; i++){
		echo("NAME: " + 
		attrInfo<i>.getName() +
		"\tTYPE: \t"+ 
		attrInfo<i>.getType() +
		"\tREAD: "+ 
		attrInfo<i>.isReadable() +
		"\tWRITE: "+ 
		attrInfo<i>.isWritable());
	    }
	}
	echo("----------------" + 
	    "Operation info--------------");
	MBeanOperationInfo[] operationInfo = 
	    info.getOperations();
	MBeanParameterInfo[] params = null;
	if(operationInfo.length>0){
		for(int i=0; 
		  i<operationInfo.length; i++){
			String param = "";
			
		params = 
		operationInfo<i>.getSignature();
		if(params.length>0){
		  for(int j=0; j<params.length;
		      j++){
		    param += 
		    params[j].getName() + "\t"; 
		  }
		}else{
			param = "NULL";
		}
		
		echo("NAME: " + 
		operationInfo<i>.getName() +
		"\t RETURN_TYPE: " + 
		operationInfo<i>.getReturnType()+
		"\t PARAMS: " + param);
		}
	}
	echo("----------------" + 
	    "Construtor info--------------");
	MBeanConstructorInfo[] constructorInfo =
	    info.getConstructors();
	if(constructorInfo.length>0){
	for(int i=0; 
	  i<constructorInfo.length; 
	  i++){
		
	    echo("NAME: " + 
	    constructorInfo<i>.getName());
	}
	}
}

private void manageSimpleBean(
    ObjectName mbeanObjectName,String mbeanName){
try{
    echo("---------------" + 
      "set state's value to 'new state'--");
    Attribute stateAttribute = 
        new Attribute("state","new state");
    server.setAttribute(mbeanObjectName, 
        stateAttribute);
    echo("state: "+server.getAttribute(
        mbeanObjectName,"state").toString());

    echo("---after invoke reset--");
    server.invoke(mbeanObjectName,
        "reset",null,null);
    echo("state: "+server.getAttribute(
        mbeanObjectName, "state").toString());
    echo("num: "+server.getAttribute(
        mbeanObjectName, "num").toString());
    }catch(Exception e){
        e.printStackTrace();
    }
}

public MBeanServer getServer() {
	return server;
}

public void setServer(MBeanServer server) {
	this.server = server;
}

private static void echo(String msg) {
System.out.println(msg);
}
}


irini   2007-05-14 22:54:15 评论:0   阅读:156   引用:0

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