package org.jgroups.demo.tankwar.jmx;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
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.MBeanException;
import javax.management.MBeanInfo;
import javax.management.MBeanOperationInfo;
import javax.management.ReflectionException;
import org.apache.log4j.Logger;
import org.jgroups.demo.tankwar.jmx.annotations.MBean;
import org.jgroups.demo.tankwar.jmx.annotations.ManagedAttribute;
import org.jgroups.demo.tankwar.jmx.annotations.ManagedOperation;
import org.jgroups.demo.tankwar.jmx.annotations.Property;
public class ResourceMBean implements DynamicMBean{
private static final Logger log = Logger.getLogger(ResourceMBean.class);
private static final Class<?>[] primitives= { int.class,
byte.class,
short.class,
long.class,
float.class,
double.class,
boolean.class,
char.class };
private static final String MBEAN_DESCRITION = "Dynamic MBean Description";
private static Pattern ATTR_NAME_TO_METHOD_NAME_PATTERN=Pattern.compile("_.");
private final Object obj;
private String description = "";
private final MBeanAttributeInfo[] attrInfo;
private final MBeanOperationInfo[] opInfo;
private final HashMap<String, AttributeEntry> atts = new HashMap<String, AttributeEntry>();
private final List<MBeanOperationInfo> ops = new ArrayList<MBeanOperationInfo>();
public ResourceMBean(Object instance) {
if(instance == null){
throw new NullPointerException("Cannot make an MBean wrapper for null instance");
}
this.obj = instance;
findDescription();
findFields();
findMethods();
attrInfo = new MBeanAttributeInfo[atts.size()];
int i = 0;
MBeanAttributeInfo info = null;
for (AttributeEntry entry : atts.values()) {
info = entry.getInfo();
attrInfo[i++] = info;
}
opInfo = new MBeanOperationInfo[ops.size()];
ops.toArray(opInfo);
}
Object getObject() {
return obj;
}
private void findDescription() {
MBean mbean=getObject().getClass().getAnnotation(MBean.class);
if(mbean != null && mbean.description() != null && mbean.description().trim().length() > 0) {
description=mbean.description();
MBeanAttributeInfo info=new MBeanAttributeInfo(ResourceMBean.MBEAN_DESCRITION,
"java.lang.String",
"MBean description",
true,
false,
false);
try {
atts.put(ResourceMBean.MBEAN_DESCRITION,
new FieldAttributeEntry(info,getClass().getDeclaredField("description")));
}
catch(NoSuchFieldException e) {
//this should not happen unless somebody removes description field
log.warn("Could not reflect field description of this class. Was it removed?");
}
}
}
private void findFields() {
//traverse class hierarchy and find all annotated fields
for(Class<?> clazz=getObject().getClass();clazz != null; clazz=clazz.getSuperclass()) {
Field[] fields=clazz.getDeclaredFields();
for(Field field:fields) {
ManagedAttribute attr=field.getAnnotation(ManagedAttribute.class);
Property prop=field.getAnnotation(Property.class);
boolean expose_prop=prop != null && prop.exposeAsManagedAttribute();
boolean expose=attr != null || expose_prop;
if(expose) {
String fieldName = attributeNameToMethodName(field.getName());
String descr=attr != null? attr.description() : prop.description();
boolean writable=attr != null? attr.writable() : prop.writable();
MBeanAttributeInfo info=new MBeanAttributeInfo(fieldName,
field.getType().getCanonicalName(),
descr,
true,
!Modifier.isFinal(field.getModifiers()) && writable,
false);
atts.put(fieldName, new FieldAttributeEntry(info, field));
}
}
}
}
public static String attributeNameToMethodName(String attr_name) {
if(attr_name.contains("_")) {
// Pattern p=Pattern.compile("_.");
Matcher m=ATTR_NAME_TO_METHOD_NAME_PATTERN.matcher(attr_name);
StringBuffer sb=new StringBuffer();
while(m.find()) {
m.appendReplacement(sb, attr_name.substring(m.end() - 1, m.end()).toUpperCase());
}
m.appendTail(sb);
char first=sb.charAt(0);
if(Character.isLowerCase(first)) {
sb.setCharAt(0, Character.toUpperCase(first));
}
return sb.toString();
} else {
if(Character.isLowerCase(attr_name.charAt(0))) {
return attr_name.substring(0, 1).toUpperCase() + attr_name.substring(1);
}
else {
return attr_name;
}
}
}
private void findMethods() {
//find all methods but don't include methods from Object class
List<Method> methods = new ArrayList<Method>(Arrays.asList(getObject().getClass().getMethods()));
List<Method> objectMethods = new ArrayList<Method>(Arrays.asList(Object.class.getMethods()));
methods.removeAll(objectMethods);
for (Method method : methods) {
//does method have @ManagedAttribute annotation?
if(method.isAnnotationPresent(ManagedAttribute.class) || method.isAnnotationPresent(Property.class)) {
exposeManagedAttribute(method);
}
//or @ManagedOperation
else if (method.isAnnotationPresent(ManagedOperation.class) || isMBeanAnnotationPresentWithExposeAll()){
exposeManagedOperation(method);
}
}
}
private boolean isMBeanAnnotationPresentWithExposeAll(){
Class<? extends Object> c=getObject().getClass();
return c.isAnnotationPresent(MBean.class) && c.getAnnotation(MBean.class).exposeAll();
}
private void exposeManagedOperation(Method method) {
ManagedOperation op = method.getAnnotation(ManagedOperation.class);
String attName=method.getName();
if(isSetMethod(method) || isGetMethod(method)) {
attName=attName.substring(3);
}
else if(isIsMethod(method)) {
attName=attName.substring(2);
}
//expose unless we already exposed matching attribute field
boolean isAlreadyExposed=atts.containsKey(attName);
if(!isAlreadyExposed) {
ops.add(new MBeanOperationInfo(op != null? op.description() : "", method));
}
}
private void exposeManagedAttribute(Method method){
String methodName=method.getName();
if(!methodName.startsWith("get") && !methodName.startsWith("set") && !methodName.startsWith("is")) {
log.warn("method name " + methodName + " doesn't start with \"get\", \"set\", or \"is\"" + ", but is annotated with @ManagedAttribute: will be ignored");
return;
}
ManagedAttribute attr = method.getAnnotation(ManagedAttribute.class);
Property prop=method.getAnnotation(Property.class);
boolean expose_prop=prop != null && prop.exposeAsManagedAttribute();
boolean expose=attr != null || expose_prop;
if(!expose){
return;
}
// Is name field of @ManagedAttributed used?
String attributeName=attr != null? attr.name() : null;
if(attributeName != null && attributeName.trim().length() > 0){
attributeName=attributeName.trim();
} else {
attributeName=null;
}
String descr=attr != null ? attr.description() : prop != null? prop.description() : null;
boolean writeAttribute=false;
MBeanAttributeInfo info=null;
if(isSetMethod(method)) { // setter
attributeName=(attributeName==null)?methodName.substring(3):attributeName;
info=new MBeanAttributeInfo(attributeName,
method.getParameterTypes()[0].getCanonicalName(),
descr,
true,
true,
false);
writeAttribute=true;
}
else { // getter
if(method.getParameterTypes().length == 0 && method.getReturnType() != java.lang.Void.TYPE) {
boolean hasSetter=atts.containsKey(attributeName);
//we found is method
if(methodName.startsWith("is")) {
attributeName=(attributeName==null)?methodName.substring(2):attributeName;
info=new MBeanAttributeInfo(attributeName,
method.getReturnType().getCanonicalName(),
descr,
true,
hasSetter,
true);
}
else {
// this has to be get
attributeName=(attributeName==null)?methodName.substring(3):attributeName;
info=new MBeanAttributeInfo(attributeName,
method.getReturnType().getCanonicalName(),
descr,
true,
hasSetter,
false);
}
} else {
log.warn("Method " + method.getName() + " must have a valid return type and zero parameters");
//silently skip this method
return;
}
}
AttributeEntry ae=atts.get(attributeName);
//is it a read method?
if(!writeAttribute) {
//we already have annotated field as read
if(ae instanceof FieldAttributeEntry && ae.getInfo().isReadable()) {
log.warn("not adding annotated method " + method + " since we already have read attribute");
}
//we already have annotated set method
else if(ae instanceof MethodAttributeEntry) {
MethodAttributeEntry mae=(MethodAttributeEntry)ae;
if(mae.hasSetMethod()) {
atts.put(attributeName,
new MethodAttributeEntry(mae.getInfo(), mae.getSetMethod(), method));
}
} //we don't have such entry
else {
atts.put(attributeName, new MethodAttributeEntry(info, findSetter(obj.getClass(), attributeName), method));
}
} //is it a set method?
else {
if(ae instanceof FieldAttributeEntry) {
//we already have annotated field as write
if(ae.getInfo().isWritable()) {
log.warn("Not adding annotated method " + methodName + " since we already have writable attribute");
}
else {
//we already have annotated field as read
//lets make the field writable
Field f = ((FieldAttributeEntry)ae).getField();
MBeanAttributeInfo i=new MBeanAttributeInfo(ae.getInfo().getName(),
f.getType().getCanonicalName(),
descr,
true,
!Modifier.isFinal(f.getModifiers()),
false);
atts.put(attributeName,new FieldAttributeEntry(i,f));
}
}
//we already have annotated getOrIs method
else if(ae instanceof MethodAttributeEntry) {
MethodAttributeEntry mae=(MethodAttributeEntry)ae;
if(mae.hasIsOrGetMethod()) {
atts.put(attributeName,
new MethodAttributeEntry(info,
method,
mae.getIsOrGetMethod()));
}
} // we don't have such entry
else {
atts.put(attributeName, new MethodAttributeEntry(info, method, findGetter(obj.getClass(), attributeName)));
}
}
}
private static boolean isSetMethod(Method method) {
return(method.getName().startsWith("set") && method.getParameterTypes().length == 1 && method.getReturnType() == java.lang.Void.TYPE);
}
private static boolean isGetMethod(Method method) {
return(method.getParameterTypes().length == 0 && method.getReturnType() != java.lang.Void.TYPE && method.getName().startsWith("get"));
}
private static boolean isIsMethod(Method method) {
return (method.getParameterTypes().length == 0 && (method.getReturnType() == boolean.class || method.getReturnType() == Boolean.class) && method.getName().startsWith("is"));
}
public static Method findGetter(Class clazz, String name) {
try {
return clazz.getMethod("get" + name);
} catch (NoSuchMethodException e) {
}
try {
return clazz.getMethod("is" + name);
} catch (NoSuchMethodException ex) {
}
return null;
}
public static Method findSetter(Class clazz, String name) {
try {
return clazz.getMethod("set" + name);
} catch (NoSuchMethodException e) {
}
return null;
}
public synchronized Object getAttribute(String name) throws AttributeNotFoundException, MBeanException, ReflectionException {
if(name == null || name.length() == 0){
throw new NullPointerException("Invalid attribute requested " + name);
}
Attribute attr = getNamedAttribute(name);
return attr.getValue();
}
public synchronized void setAttribute(Attribute attribute) throws AttributeNotFoundException, InvalidAttributeValueException, MBeanException, ReflectionException {
if(attribute == null || attribute.getName() == null){
throw new NullPointerException("Invalid attribute requested " + attribute);
}
setNamedAttribute(attribute);
}
public synchronized AttributeList getAttributes(String[] names) {
AttributeList al = new AttributeList();
for (String name : names) {
Attribute attr = getNamedAttribute(name);
if (attr != null) {
al.add(attr);
} else {
log.warn("Did not find attribute " + name);
}
}
return al;
}
public synchronized AttributeList setAttributes(AttributeList list) {
AttributeList results = new AttributeList();
for (int i = 0; i < list.size(); i++) {
Attribute attr = (Attribute) list.get(i);
if (setNamedAttribute(attr)) {
results.add(attr);
} else {
log.warn("Failed to update attribute name " + attr.getName() + " with value " + attr.getValue());
}
}
return results;
}
public Object invoke(String name, Object[] args, String[] sig) throws MBeanException, ReflectionException {
try {
Class<?>[] classes = new Class[sig.length];
for (int i = 0; i < classes.length; i++) {
classes[i] = getClassForName(sig[i]);
}
Method method = getObject().getClass().getMethod(name, classes);
return method.invoke(getObject(), args);
} catch (Exception e) {
throw new MBeanException(e);
}
}
public synchronized MBeanInfo getMBeanInfo() {
return new MBeanInfo(getObject().getClass().getCanonicalName(),
description,
attrInfo,
null,
opInfo,
null);
}
public static Class<?> getClassForName(String name) throws ClassNotFoundException {
try {
return Class.forName(name);
} catch (ClassNotFoundException cnfe) {
//Could be a primitive - let's check
for(int i=0;i < primitives.length;i++) {
if(name.equals(primitives[i].getName())) {
return primitives[i];
}
}
}
throw new ClassNotFoundException("Class " + name + " cannot be found");
}
private boolean setNamedAttribute(Attribute attribute) {
boolean result = false;
AttributeEntry entry = atts.get(attribute.getName());
if (entry != null) {
try {
entry.invoke(attribute);
result = true;
} catch (Exception e) {
log.warn("Exception while writing value for attribute " + attribute.getName(), e);
}
} else {
log.warn("Could not invoke set on attribute " + attribute.getName() + " with value " + attribute.getValue());
}
return result;
}
private Attribute getNamedAttribute(String name) {
Attribute result = null;
if (name.equals(ResourceMBean.MBEAN_DESCRITION)) {
result = new Attribute(ResourceMBean.MBEAN_DESCRITION, this.description);
} else {
AttributeEntry entry = atts.get(name);
if (entry != null) {
try {
result = new Attribute(name, entry.invoke(null));
} catch (Exception e) {
log.warn("Exception while reading value of attribute " + name, e);
}
} else {
log.warn("Did not find queried attribute with name " + name);
}
}
return result;
}
private interface AttributeEntry {
public Object invoke(Attribute a) throws Exception;
public MBeanAttributeInfo getInfo();
}
private class FieldAttributeEntry implements AttributeEntry {
private final MBeanAttributeInfo info;
private final Field field;
public FieldAttributeEntry(final MBeanAttributeInfo info,final Field field) {
super();
this.info=info;
this.field=field;
if(!field.isAccessible()) {
field.setAccessible(true);
}
}
public Field getField(){
return field;
}
public Object invoke(Attribute a) throws Exception {
if(a == null) {
return field.get(getObject());
}
else {
field.set(getObject(), a.getValue());
return null;
}
}
public MBeanAttributeInfo getInfo() {
return info;
}
}
private class MethodAttributeEntry implements AttributeEntry {
final MBeanAttributeInfo info;
final Method isOrGetmethod;
final Method setMethod;
public MethodAttributeEntry(final MBeanAttributeInfo info,
final Method setMethod,
final Method isOrGetMethod) {
super();
this.info=info;
this.setMethod=setMethod;
this.isOrGetmethod=isOrGetMethod;
}
public Object invoke(Attribute a) throws Exception {
if(a == null && isOrGetmethod != null)
return isOrGetmethod.invoke(getObject());
else if(a != null && setMethod != null)
return setMethod.invoke(getObject(), a.getValue());
else
return null;
}
public MBeanAttributeInfo getInfo() {
return info;
}
public boolean hasIsOrGetMethod() {
return isOrGetmethod != null;
}
public boolean hasSetMethod() {
return setMethod != null;
}
public Method getIsOrGetMethod() {
return isOrGetmethod;
}
public Method getSetMethod() {
return setMethod;
}
}
}