精通spring源代码精通spring源代码

package chapter19.jmx.dynamic; 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; /** * 简单动态MBean * - "State"属性:可读可写 * - "NbChanges"属性:只读 * - "reset()" :方法 * 注意:动态MBean必须定义一个public的构造函数,且必须通过MBeanInfo来管理 */ public class SimpleDynamic implements DynamicMBean { private String state = "initial state"; private int nbChanges = 0; private int nbResets = 0; private String dClassName = this.getClass().getName(); private String dDescription = "Simple implementation of a dynamic MBean."; public String getState() { return state; } public void setState(String s) { state = s; nbChanges++; } public Integer getNbChanges() { return new Integer(nbChanges); } public void reset() { state = "initial state"; nbChanges = 0; nbResets++; } public Integer getNbResets() { return new Integer(nbResets); } private MBeanAttributeInfo[] dAttributes = new MBeanAttributeInfo[2]; private MBeanConstructorInfo[] dConstructors = new MBeanConstructorInfo[1]; private MBeanOperationInfo[] dOperations = new MBeanOperationInfo[1]; private MBeanInfo dMBeanInfo = null; public SimpleDynamic() { //建立辅助信息 buildDynamicMBeanInfo(); } public Object getAttribute(String attribute_name) throws AttributeNotFoundException, MBeanException, ReflectionException { // 检查已知属性,调用已知方法 if (attribute_name.equals("State")) { return getState(); } if (attribute_name.equals("NbChanges")) { return getNbChanges(); } // 如果属性不可识别,抛出异常 throw (new AttributeNotFoundException("Cannot find " + attribute_name + " attribute in " + dClassName)); } public void setAttribute(Attribute attribute) throws AttributeNotFoundException, InvalidAttributeValueException, MBeanException, ReflectionException { String name = attribute.getName(); Object value = attribute.getValue(); if (name.equals("State")) { try { if ((Class.forName("java.lang.String")).isAssignableFrom(value .getClass())) { setState((String) value); } } catch (ClassNotFoundException e) { e.printStackTrace(); } } else if (name.equals("NbChanges")) { //由于"NbChanges" 属性是只读的,所以抛出异常 throw (new AttributeNotFoundException("Cannot set attribute " + name + " because it is read-only")); } } public AttributeList getAttributes(String[] attributeNames) { AttributeList resultList = new AttributeList(); if (attributeNames.length == 0) return resultList; for (int i = 0; i < attributeNames.length; i++) { try { Object value = getAttribute((String) attributeNames[i]); resultList.add(new Attribute(attributeNames[i], value)); } catch (Exception e) { e.printStackTrace(); } } return (resultList); } public AttributeList setAttributes(AttributeList attributes) { AttributeList resultList = new AttributeList(); if (attributes.isEmpty()) return resultList; for (Iterator i = attributes.iterator(); i.hasNext();) { Attribute attr = (Attribute) i.next(); try { setAttribute(attr); String name = attr.getName(); Object value = getAttribute(name); resultList.add(new Attribute(name, value)); } catch (Exception e) { e.printStackTrace(); } } return resultList; } /** * 调用操作 */ public Object invoke(String operationName, Object params[], String signature[]) throws MBeanException, ReflectionException { if (operationName.equals("reset")) { reset(); } return null; } public MBeanInfo getMBeanInfo() { return (dMBeanInfo); } /** * 构造辅助信息,这里用了很多辅助类 */ private void buildDynamicMBeanInfo() { //Bean属性信息 dAttributes[0] = new MBeanAttributeInfo("State", "java.lang.String", "State: state string.", true, true, false); dAttributes[1] = new MBeanAttributeInfo("NbChanges", "java.lang.Integer", "NbChanges: number of times the State string " + "has been changed.", true, false, false); //Bean构造函数信息... Constructor[] constructors = this.getClass().getConstructors(); dConstructors[0] = new MBeanConstructorInfo( "SimpleDynamic(): Constructs a SimpleDynamic object", constructors[0]); //Bean操作和方法参数... MBeanParameterInfo[] params = null; dOperations[0] = new MBeanOperationInfo( "reset", "reset(): reset State and NbChanges attributes to their initial values", params, "void", MBeanOperationInfo.ACTION); dMBeanInfo = new MBeanInfo(dClassName, dDescription, dAttributes, dConstructors, dOperations, new MBeanNotificationInfo[0]); } }