Spring Framework example source code file (AbstractReflectiveMBeanInfoAssembler.java)

This example Spring Framework source code file (AbstractReflectiveMBeanInfoAssembler.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 - Spring Framework tags/keywords

arraylist, bean, descriptor, integer, integer, javabean, list, management, mbeanparameterinfo, method, method, modelmbeanattributeinfo, modelmbeanoperationinfo, modelmbeanoperationinfo, propertydescriptor, reflection, string, string, util

The Spring Framework AbstractReflectiveMBeanInfoAssembler.java source code

/*
 * Copyright 2002-2006 the original author or authors.
 *
 * Licensed 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.springframework.jmx.export.assembler;

import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;

import javax.management.Descriptor;
import javax.management.JMException;
import javax.management.MBeanOperationInfo;
import javax.management.MBeanParameterInfo;
import javax.management.modelmbean.ModelMBeanAttributeInfo;
import javax.management.modelmbean.ModelMBeanOperationInfo;

import org.springframework.aop.framework.AopProxyUtils;
import org.springframework.aop.support.AopUtils;
import org.springframework.beans.BeanUtils;
import org.springframework.core.JdkVersion;
import org.springframework.jmx.support.JmxUtils;

/**
 * Builds on the {@link AbstractMBeanInfoAssembler} superclass to
 * add a basic algorithm for building metadata based on the
 * reflective metadata of the MBean class.
 *
 * <p>The logic for creating MBean metadata from the reflective metadata
 * is contained in this class, but this class makes no decisions as to
 * which methods and properties are to be exposed. Instead it gives
 * subclasses a chance to 'vote' on each property or method through
 * the <code>includeXXX methods.
 *
 * <p>Subclasses are also given the opportunity to populate attribute
 * and operation metadata with additional descriptors once the metadata
 * is assembled through the <code>populateXXXDescriptor methods.
 *
 * @author Rob Harrop
 * @author Juergen Hoeller
 * @since 1.2
 * @see #includeOperation
 * @see #includeReadAttribute
 * @see #includeWriteAttribute
 * @see #populateAttributeDescriptor
 * @see #populateOperationDescriptor
 */
public abstract class AbstractReflectiveMBeanInfoAssembler extends AbstractMBeanInfoAssembler {

	/**
	 * Identifies a getter method in a JMX {@link Descriptor}.
	 */
	protected static final String FIELD_GET_METHOD = "getMethod";

	/**
	 * Identifies a setter method in a JMX {@link Descriptor}.
	 */
	protected static final String FIELD_SET_METHOD = "setMethod";

	/**
	 * Constant identifier for the role field in a JMX {@link Descriptor}.
	 */
	protected static final String FIELD_ROLE = "role";

	/**
	 * Constant identifier for the getter role field value in a JMX {@link Descriptor}.
	 */
	protected static final String ROLE_GETTER = "getter";

	/**
	 * Constant identifier for the setter role field value in a JMX {@link Descriptor}.
	 */
	protected static final String ROLE_SETTER = "setter";

	/**
	 * Identifies an operation (method) in a JMX {@link Descriptor}.
	 */
	protected static final String ROLE_OPERATION = "operation";

	/**
	 * Constant identifier for the visibility field in a JMX {@link Descriptor}.
	 */
	protected static final String FIELD_VISIBILITY = "visibility";

	/**
	 * Lowest visibility, used for operations that correspond to
	 * accessors or mutators for attributes.
	 * @see #FIELD_VISIBILITY
	 */
	protected static final Integer ATTRIBUTE_OPERATION_VISIBILITY = new Integer(4);

	/**
	 * Constant identifier for the class field in a JMX {@link Descriptor}.
	 */
	protected static final String FIELD_CLASS = "class";
	/**
	 * Constant identifier for the log field in a JMX {@link Descriptor}.
	 */
	protected static final String FIELD_LOG = "log";
	
	/**
	 * Constant identifier for the logfile field in a JMX {@link Descriptor}.
	 */
	protected static final String FIELD_LOG_FILE = "logFile";
	
	/**
	 * Constant identifier for the currency time limit field in a JMX {@link Descriptor}.
	 */
	protected static final String FIELD_CURRENCY_TIME_LIMIT = "currencyTimeLimit";

	/**
	 * Constant identifier for the default field in a JMX {@link Descriptor}.
	 */
	protected static final String FIELD_DEFAULT = "default";

	/**
	 * Constant identifier for the persistPolicy field in a JMX {@link Descriptor}.
	 */
	protected static final String FIELD_PERSIST_POLICY = "persistPolicy";

	/**
	 * Constant identifier for the persistPeriod field in a JMX {@link Descriptor}.
	 */
	protected static final String FIELD_PERSIST_PERIOD = "persistPeriod";

	/**
	 * Constant identifier for the persistLocation field in a JMX {@link Descriptor}.
	 */
	protected static final String FIELD_PERSIST_LOCATION = "persistLocation";

	/**
	 * Constant identifier for the persistName field in a JMX {@link Descriptor}.
	 */
	protected static final String FIELD_PERSIST_NAME = "persistName";


	/**
	 * Default value for the JMX field "currencyTimeLimit".
	 */
	private Integer defaultCurrencyTimeLimit;

	/**
	 * Indicates whether or not strict casing is being used for attributes.
	 */
	private boolean useStrictCasing = true;

	private boolean exposeClassDescriptor = false;


	/**
	 * Set the default for the JMX field "currencyTimeLimit".
	 * The default will usually indicate to never cache attribute values.
	 * <p>Default is none, not explicitly setting that field, as recommended by the
	 * JMX 1.2 specification. This should result in "never cache" behavior, always
	 * reading attribute values freshly (which corresponds to a "currencyTimeLimit"
	 * of <code>-1 in JMX 1.2).
	 * <p>However, some JMX implementations (that do not follow the JMX 1.2 spec
	 * in that respect) might require an explicit value to be set here to get
	 * "never cache" behavior: for example, JBoss 3.2.x.
	 * <p>Note that the "currencyTimeLimit" value can also be specified on a
	 * managed attribute or operation. The default value will apply if not
	 * overridden with a "currencyTimeLimit" value <code>>= 0 there:
	 * a metadata "currencyTimeLimit" value of <code>-1 indicates
	 * to use the default; a value of <code>0 indicates to "always cache"
	 * and will be translated to <code>Integer.MAX_VALUE; a positive
	 * value indicates the number of cache seconds.
	 * @see org.springframework.jmx.export.metadata.AbstractJmxAttribute#setCurrencyTimeLimit
	 * @see #applyCurrencyTimeLimit(javax.management.Descriptor, int)
	 */
	public void setDefaultCurrencyTimeLimit(Integer defaultCurrencyTimeLimit) {
		this.defaultCurrencyTimeLimit = defaultCurrencyTimeLimit;
	}

	/**
	 * Return default value for the JMX field "currencyTimeLimit", if any.
	 */
	protected Integer getDefaultCurrencyTimeLimit() {
		return this.defaultCurrencyTimeLimit;
	}

	/**
	 * Set whether to use strict casing for attributes. Enabled by default.
	 * <p>When using strict casing, a JavaBean property with a getter such as
	 * <code>getFoo() translates to an attribute called Foo.
	 * With strict casing disabled, <code>getFoo() would translate to just
	 * <code>foo.
	 */
	public void setUseStrictCasing(boolean useStrictCasing) {
		this.useStrictCasing = useStrictCasing;
	}

	/**
	 * Return whether strict casing for attributes is enabled.
	 */
	protected boolean isUseStrictCasing() {
		return useStrictCasing;
	}

	/**
	 * Set whether to expose the JMX descriptor field "class" for managed operations.
	 * Default is "false", letting the JMX implementation determine the actual class
	 * through reflection.
	 * <p>Set this property to true for JMX implementations that
	 * require the "class" field to be specified, for example WebLogic's.
	 * In that case, Spring will expose the target class name there, in case of
	 * a plain bean instance or a CGLIB proxy. When encountering a JDK dynamic
	 * proxy, the <b>first interface implemented by the proxy will be specified.
	 * <p>WARNING: Review your proxy definitions when exposing a JDK dynamic
	 * proxy through JMX, in particular with this property turned to <code>true:
	 * the specified interface list should start with your management interface in
	 * this case, with all other interfaces following. In general, consider exposing
	 * your target bean directly or a CGLIB proxy for it instead.
	 * @see #getClassForDescriptor(Object)
	 */
	public void setExposeClassDescriptor(boolean exposeClassDescriptor) {
		this.exposeClassDescriptor = exposeClassDescriptor;
	}

	/**
	 * Return whether to expose the JMX descriptor field "class" for managed operations.
	 */
	protected boolean isExposeClassDescriptor() {
		return exposeClassDescriptor;
	}


	/**
	 * Iterate through all properties on the MBean class and gives subclasses
	 * the chance to vote on the inclusion of both the accessor and mutator.
	 * If a particular accessor or mutator is voted for inclusion, the appropriate
	 * metadata is assembled and passed to the subclass for descriptor population.
	 * @param managedBean the bean instance (might be an AOP proxy)
	 * @param beanKey the key associated with the MBean in the beans map
	 * of the <code>MBeanExporter
	 * @return the attribute metadata
	 * @throws JMException in case of errors
	 * @see #populateAttributeDescriptor
	 */
	protected ModelMBeanAttributeInfo[] getAttributeInfo(Object managedBean, String beanKey) throws JMException {
		PropertyDescriptor[] props = BeanUtils.getPropertyDescriptors(getClassToExpose(managedBean));
		List infos = new ArrayList();

		for (int i = 0; i < props.length; i++) {
			Method getter = props[i].getReadMethod();
			if (getter != null && getter.getDeclaringClass() == Object.class) {
				continue;
			}
			if (getter != null && !includeReadAttribute(getter, beanKey)) {
				getter = null;
			}

			Method setter = props[i].getWriteMethod();
			if (setter != null && !includeWriteAttribute(setter, beanKey)) {
				setter = null;
			}

			if (getter != null || setter != null) {
				// If both getter and setter are null, then this does not need exposing.
				String attrName = JmxUtils.getAttributeName(props[i], isUseStrictCasing());
				String description = getAttributeDescription(props[i], beanKey);
				ModelMBeanAttributeInfo info = new ModelMBeanAttributeInfo(attrName, description, getter, setter);

				Descriptor desc = info.getDescriptor();
				if (getter != null) {
					desc.setField(FIELD_GET_METHOD, getter.getName());
				}
				if (setter != null) {
					desc.setField(FIELD_SET_METHOD, setter.getName());
				}

				populateAttributeDescriptor(desc, getter, setter, beanKey);
				info.setDescriptor(desc);
				infos.add(info);
			}
		}

		return (ModelMBeanAttributeInfo[]) infos.toArray(new ModelMBeanAttributeInfo[infos.size()]);
	}

	/**
	 * Iterate through all methods on the MBean class and gives subclasses the chance
	 * to vote on their inclusion. If a particular method corresponds to the accessor
	 * or mutator of an attribute that is inclued in the managment interface, then
	 * the corresponding operation is exposed with the "role" descriptor
	 * field set to the appropriate value.
	 * @param managedBean the bean instance (might be an AOP proxy)
	 * @param beanKey the key associated with the MBean in the beans map
	 * of the <code>MBeanExporter
	 * @return the operation metadata
	 * @see #populateOperationDescriptor
	 */
	protected ModelMBeanOperationInfo[] getOperationInfo(Object managedBean, String beanKey) {
		Method[] methods = getClassToExpose(managedBean).getMethods();
		List infos = new ArrayList();

		for (int i = 0; i < methods.length; i++) {
			Method method = methods[i];
			if (JdkVersion.isAtLeastJava15() && method.isSynthetic()) {
				continue;
			}
			if (method.getDeclaringClass().equals(Object.class)) {
				continue;
			}

			ModelMBeanOperationInfo info = null;
			PropertyDescriptor pd = BeanUtils.findPropertyForMethod(method);
			if (pd != null) {
				if ((method.equals(pd.getReadMethod()) && includeReadAttribute(method, beanKey)) ||
						(method.equals(pd.getWriteMethod()) && includeWriteAttribute(method, beanKey))) {
					// Attributes need to have their methods exposed as
					// operations to the JMX server as well.
					info = createModelMBeanOperationInfo(method, pd.getName(), beanKey);
					Descriptor desc = info.getDescriptor();
					if (method.equals(pd.getReadMethod())) {
						desc.setField(FIELD_ROLE, ROLE_GETTER);
					}
					else {
						desc.setField(FIELD_ROLE, ROLE_SETTER);
					}
					desc.setField(FIELD_VISIBILITY, ATTRIBUTE_OPERATION_VISIBILITY);
					if (isExposeClassDescriptor()) {
						desc.setField(FIELD_CLASS, getClassForDescriptor(managedBean).getName());
					}
					info.setDescriptor(desc);
				}
			}
			else if (includeOperation(method, beanKey)) {
				info = createModelMBeanOperationInfo(method, method.getName(), beanKey);
				Descriptor desc = info.getDescriptor();
				desc.setField(FIELD_ROLE, ROLE_OPERATION);
				if (isExposeClassDescriptor()) {
					desc.setField(FIELD_CLASS, getClassForDescriptor(managedBean).getName());
				}
				populateOperationDescriptor(desc, method, beanKey);
				info.setDescriptor(desc);
			}

			if (info != null) {
				infos.add(info);
			}
		}

		return (ModelMBeanOperationInfo[]) infos.toArray(new ModelMBeanOperationInfo[infos.size()]);
	}

	/**
	 * Creates an instance of <code>ModelMBeanOperationInfo for the
	 * given method. Populates the parameter info for the operation.
	 * @param method the <code>Method to create a ModelMBeanOperationInfo for
	 * @param name the name for the operation info
	 * @param beanKey the key associated with the MBean in the beans map
	 * of the <code>MBeanExporter
	 * @return the <code>ModelMBeanOperationInfo
	 */
	protected ModelMBeanOperationInfo createModelMBeanOperationInfo(Method method, String name, String beanKey) {
		MBeanParameterInfo[] params = getOperationParameters(method, beanKey);
		if (params.length == 0) {
			return new ModelMBeanOperationInfo(getOperationDescription(method, beanKey), method);
		}
		else {
			return new ModelMBeanOperationInfo(name,
				getOperationDescription(method, beanKey),
				getOperationParameters(method, beanKey),
				method.getReturnType().getName(),
				MBeanOperationInfo.UNKNOWN);
		}
	}

	/**
	 * Return the class to be used for the JMX descriptor field "class".
	 * Only applied when the "exposeClassDescriptor" property is "true".
	 * <p>Default implementation returns the first implemented interface
	 * for a JDK proxy, and the target class else.
	 * @param managedBean the bean instance (might be an AOP proxy)
	 * @return the class to expose in the descriptor field "class"
	 * @see #setExposeClassDescriptor
	 * @see #getClassToExpose(Class)
	 * @see org.springframework.aop.framework.AopProxyUtils#proxiedUserInterfaces(Object)
	 */
	protected Class getClassForDescriptor(Object managedBean) {
		if (AopUtils.isJdkDynamicProxy(managedBean)) {
			return AopProxyUtils.proxiedUserInterfaces(managedBean)[0];
		}
		return getClassToExpose(managedBean);
	}


	/**
	 * Allows subclasses to vote on the inclusion of a particular attribute accessor.
	 * @param method the accessor <code>Method
	 * @param beanKey the key associated with the MBean in the beans map
	 * of the <code>MBeanExporter
	 * @return <code>true if the accessor should be included in the management interface,
	 * otherwise <code>false
	 */
	protected abstract boolean includeReadAttribute(Method method, String beanKey);

	/**
	 * Allows subclasses to vote on the inclusion of a particular attribute mutator.
	 * @param method the mutator <code>Method.
	 * @param beanKey the key associated with the MBean in the beans map
	 * of the <code>MBeanExporter
	 * @return <code>true if the mutator should be included in the management interface,
	 * otherwise <code>false
	 */
	protected abstract boolean includeWriteAttribute(Method method, String beanKey);

	/**
	 * Allows subclasses to vote on the inclusion of a particular operation.
	 * @param method the operation method
	 * @param beanKey the key associated with the MBean in the beans map
	 * of the <code>MBeanExporter
	 * @return whether the operation should be included in the management interface
	 */
	protected abstract boolean includeOperation(Method method, String beanKey);


	/**
	 * Get the description for a particular attribute.
	 * <p>Default implementation returns a description for the operation
	 * that is the name of corresponding <code>Method.
	 * @param propertyDescriptor the PropertyDescriptor for the attribute
	 * @param beanKey the key associated with the MBean in the beans map
	 * of the <code>MBeanExporter
	 * @return the description for the attribute
	 */
	protected String getAttributeDescription(PropertyDescriptor propertyDescriptor, String beanKey) {
		return propertyDescriptor.getDisplayName();
	}

	/**
	 * Get the description for a particular operation.
	 * <p>Default implementation returns a description for the operation
	 * that is the name of corresponding <code>Method.
	 * @param method the operation method
	 * @param beanKey the key associated with the MBean in the beans map
	 * of the <code>MBeanExporter
	 * @return the description for the operation
	 */
	protected String getOperationDescription(Method method, String beanKey) {
		return method.getName();
	}

	/**
	 * Create parameter info for the given method. Default implementation
	 * returns an empty arry of <code>MBeanParameterInfo.
	 * @param method the <code>Method to get the parameter information for
	 * @param beanKey the key associated with the MBean in the beans map
	 * of the <code>MBeanExporter
	 * @return the <code>MBeanParameterInfo array
	 */
	protected MBeanParameterInfo[] getOperationParameters(Method method, String beanKey) {
		return new MBeanParameterInfo[0];
	}


	/**
	 * Allows subclasses to add extra fields to the <code>Descriptor for an
	 * MBean. Default implementation sets the <code>currencyTimeLimit field to
	 * the specified "defaultCurrencyTimeLimit", if any (by default none).
	 * @param descriptor the <code>Descriptor for the MBean resource.
	 * @param managedBean the bean instance (might be an AOP proxy)
	 * @param beanKey the key associated with the MBean in the beans map
	 * of the <code>MBeanExporter
	 * @see #setDefaultCurrencyTimeLimit(Integer)
	 * @see #applyDefaultCurrencyTimeLimit(javax.management.Descriptor)
	 */
	protected void populateMBeanDescriptor(Descriptor descriptor, Object managedBean, String beanKey) {
		applyDefaultCurrencyTimeLimit(descriptor);
	}

	/**
	 * Allows subclasses to add extra fields to the <code>Descriptor for a particular
	 * attribute. Default implementation sets the <code>currencyTimeLimit field to
	 * the specified "defaultCurrencyTimeLimit", if any (by default none).
	 * @param desc the attribute descriptor
	 * @param getter the accessor method for the attribute
	 * @param setter the mutator method for the attribute
	 * @param beanKey the key associated with the MBean in the beans map
	 * of the <code>MBeanExporter
	 * @see #setDefaultCurrencyTimeLimit(Integer)
	 * @see #applyDefaultCurrencyTimeLimit(javax.management.Descriptor)
	 */
	protected void populateAttributeDescriptor(Descriptor desc, Method getter, Method setter, String beanKey) {
		applyDefaultCurrencyTimeLimit(desc);
	}

	/**
	 * Allows subclasses to add extra fields to the <code>Descriptor for a particular
	 * operation. Default implementation sets the <code>currencyTimeLimit field to
	 * the specified "defaultCurrencyTimeLimit", if any (by default none).
	 * @param desc the operation descriptor
	 * @param method the method corresponding to the operation
	 * @param beanKey the key associated with the MBean in the beans map
	 * of the <code>MBeanExporter
	 * @see #setDefaultCurrencyTimeLimit(Integer)
	 * @see #applyDefaultCurrencyTimeLimit(javax.management.Descriptor)
	 */
	protected void populateOperationDescriptor(Descriptor desc, Method method, String beanKey) {
		applyDefaultCurrencyTimeLimit(desc);
	}

	/**
	 * Set the <code>currencyTimeLimit field to the specified
	 * "defaultCurrencyTimeLimit", if any (by default none).
	 * @param desc the JMX attribute or operation descriptor
	 * @see #setDefaultCurrencyTimeLimit(Integer)
	 */
	protected final void applyDefaultCurrencyTimeLimit(Descriptor desc) {
		if (getDefaultCurrencyTimeLimit() != null) {
			desc.setField(FIELD_CURRENCY_TIME_LIMIT, getDefaultCurrencyTimeLimit().toString());
		}
	}

	/**
	 * Apply the given JMX "currencyTimeLimit" value to the given descriptor.
	 * <p>Default implementation sets a value >0 as-is (as number of cache seconds),
	 * turns a value of <code>0 into Integer.MAX_VALUE ("always cache")
	 * and sets the "defaultCurrencyTimeLimit" (if any, indicating "never cache") in case of
	 * a value <code><0. This follows the recommendation in the JMX 1.2 specification.
	 * @param desc the JMX attribute or operation descriptor
	 * @param currencyTimeLimit the "currencyTimeLimit" value to apply
	 * @see #setDefaultCurrencyTimeLimit(Integer)
	 * @see #applyDefaultCurrencyTimeLimit(javax.management.Descriptor)
	 */
	protected void applyCurrencyTimeLimit(Descriptor desc, int currencyTimeLimit) {
		if (currencyTimeLimit > 0) {
			// number of cache seconds
			desc.setField(FIELD_CURRENCY_TIME_LIMIT, Integer.toString(currencyTimeLimit));
		}
		else if (currencyTimeLimit == 0) {
			// "always cache"
			desc.setField(FIELD_CURRENCY_TIME_LIMIT, Integer.toString(Integer.MAX_VALUE));
		}
		else {
			// "never cache"
			applyDefaultCurrencyTimeLimit(desc);
		}
	}

}