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Spring Framework example source code file (MetadataMBeanInfoAssembler.java)

This example Spring Framework source code file (MetadataMBeanInfoAssembler.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

bean, illegalargumentexception, javabean, jmxattributesource, managedattribute, managedattribute, managedresource, management, mbeanparameterinfo, metadatambeaninfoassembler, method, method, object, object, propertydescriptor, reflection, string, string

The Spring Framework MetadataMBeanInfoAssembler.java source code

/*
 * Copyright 2002-2007 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 javax.management.Descriptor;
import javax.management.MBeanParameterInfo;
import javax.management.modelmbean.ModelMBeanNotificationInfo;

import org.springframework.aop.support.AopUtils;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.jmx.export.metadata.InvalidMetadataException;
import org.springframework.jmx.export.metadata.JmxAttributeSource;
import org.springframework.jmx.export.metadata.JmxMetadataUtils;
import org.springframework.jmx.export.metadata.ManagedAttribute;
import org.springframework.jmx.export.metadata.ManagedNotification;
import org.springframework.jmx.export.metadata.ManagedOperation;
import org.springframework.jmx.export.metadata.ManagedOperationParameter;
import org.springframework.jmx.export.metadata.ManagedResource;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;

/**
 * Implementation of the {@link org.springframework.jmx.export.assembler.MBeanInfoAssembler}
 * interface that reads the management interface information from source level metadata.
 *
 * <p>Uses the {@link JmxAttributeSource} strategy interface, so that
 * metadata can be read using any supported implementation. Out of the box,
 * two strategies are included:
 * <ul>
 * <li>AttributesJmxAttributeSource, for Commons Attributes
 * <li>AnnotationJmxAttributeSource, for JDK 1.5+ annotations
 * </ul>
 *
 * @author Rob Harrop
 * @author Juergen Hoeller
 * @since 1.2
 * @see #setAttributeSource
 * @see org.springframework.jmx.export.metadata.AttributesJmxAttributeSource
 * @see org.springframework.jmx.export.annotation.AnnotationJmxAttributeSource
 */
public class MetadataMBeanInfoAssembler extends AbstractReflectiveMBeanInfoAssembler
		implements AutodetectCapableMBeanInfoAssembler, InitializingBean {

	private JmxAttributeSource attributeSource;


	/**
	 * Create a new <code>MetadataMBeanInfoAssembler which needs to be
	 * configured through the {@link #setAttributeSource} method.
	 */
	public MetadataMBeanInfoAssembler() {
	}

	/**
	 * Create a new <code>MetadataMBeanInfoAssembler for the given
	 * <code>JmxAttributeSource.
	 * @param attributeSource the JmxAttributeSource to use
	 */
	public MetadataMBeanInfoAssembler(JmxAttributeSource attributeSource) {
		Assert.notNull(attributeSource, "JmxAttributeSource must not be null");
		this.attributeSource = attributeSource;
	}


	/**
	 * Set the <code>JmxAttributeSource implementation to use for
	 * reading the metadata from the bean class.
	 * @see org.springframework.jmx.export.metadata.AttributesJmxAttributeSource
	 * @see org.springframework.jmx.export.annotation.AnnotationJmxAttributeSource
	 */
	public void setAttributeSource(JmxAttributeSource attributeSource) {
		Assert.notNull(attributeSource, "JmxAttributeSource must not be null");
		this.attributeSource = attributeSource;
	}

	public void afterPropertiesSet() {
		if (this.attributeSource == null) {
			throw new IllegalArgumentException("Property 'attributeSource' is required");
		}
	}


	/**
	 * Throws an IllegalArgumentException if it encounters a JDK dynamic proxy.
	 * Metadata can only be read from target classes and CGLIB proxies!
	 */
	protected void checkManagedBean(Object managedBean) throws IllegalArgumentException {
		if (AopUtils.isJdkDynamicProxy(managedBean)) {
			throw new IllegalArgumentException(
					"MetadataMBeanInfoAssembler does not support JDK dynamic proxies - " +
					"export the target beans directly or use CGLIB proxies instead");
		}
	}

	/**
	 * Used for autodetection of beans. Checks to see if the bean's class has a
	 * <code>ManagedResource attribute. If so it will add it list of included beans.
	 * @param beanClass the class of the bean
	 * @param beanName the name of the bean in the bean factory
	 */
	public boolean includeBean(Class beanClass, String beanName) {
		return (this.attributeSource.getManagedResource(getClassToExpose(beanClass)) != null);
	}

	/**
	 * Vote on the inclusion of an attribute accessor.
	 * @param method the accessor method
	 * @param beanKey the key associated with the MBean in the beans map
	 * @return whether the method has the appropriate metadata
	 */
	protected boolean includeReadAttribute(Method method, String beanKey) {
		return hasManagedAttribute(method);
	}

	/**
	 * Votes on the inclusion of an attribute mutator.
	 * @param method the mutator method
	 * @param beanKey the key associated with the MBean in the beans map
	 * @return whether the method has the appropriate metadata
	 */
	protected boolean includeWriteAttribute(Method method, String beanKey) {
		return hasManagedAttribute(method);
	}

	/**
	 * Votes on the inclusion of an operation.
	 * @param method the operation method
	 * @param beanKey the key associated with the MBean in the beans map
	 * @return whether the method has the appropriate metadata
	 */
	protected boolean includeOperation(Method method, String beanKey) {
		PropertyDescriptor pd = BeanUtils.findPropertyForMethod(method);
		if (pd != null) {
			return hasManagedAttribute(method);
		}
		else {
			return hasManagedOperation(method);
		}
	}

	/**
	 * Checks to see if the given Method has the <code>ManagedAttribute attribute.
	 */
	private boolean hasManagedAttribute(Method method) {
		return (this.attributeSource.getManagedAttribute(method) != null);
	}

	/**
	 * Checks to see if the given Method has the <code>ManagedOperation attribute.
	 * @param method the method to check
	 */
	private boolean hasManagedOperation(Method method) {
		return (this.attributeSource.getManagedOperation(method) != null);
	}


	/**
	 * Reads managed resource description from the source level metadata.
	 * Returns an empty <code>String if no description can be found.
	 */
	protected String getDescription(Object managedBean, String beanKey) {
		ManagedResource mr = this.attributeSource.getManagedResource(getClassToExpose(managedBean));
		return (mr != null ? mr.getDescription() : "");
	}

	/**
	 * Creates a description for the attribute corresponding to this property
	 * descriptor. Attempts to create the description using metadata from either
	 * the getter or setter attributes, otherwise uses the property name.
	 */
	protected String getAttributeDescription(PropertyDescriptor propertyDescriptor, String beanKey) {
		Method readMethod = propertyDescriptor.getReadMethod();
		Method writeMethod = propertyDescriptor.getWriteMethod();

		ManagedAttribute getter =
				(readMethod != null) ? this.attributeSource.getManagedAttribute(readMethod) : null;
		ManagedAttribute setter =
				(writeMethod != null) ? this.attributeSource.getManagedAttribute(writeMethod) : null;

		if (getter != null && StringUtils.hasText(getter.getDescription())) {
			return getter.getDescription();
		}
		else if (setter != null && StringUtils.hasText(setter.getDescription())) {
			return setter.getDescription();
		}
		return propertyDescriptor.getDisplayName();
	}

	/**
	 * Retrieves the description for the supplied <code>Method from the
	 * metadata. Uses the method name is no description is present in the metadata.
	 */
	protected String getOperationDescription(Method method, String beanKey) {
		PropertyDescriptor pd = BeanUtils.findPropertyForMethod(method);
		if (pd != null) {
			ManagedAttribute ma = this.attributeSource.getManagedAttribute(method);
			if (ma != null && StringUtils.hasText(ma.getDescription())) {
				return ma.getDescription();
			}
			return method.getName();
		}
		else {
			ManagedOperation mo = this.attributeSource.getManagedOperation(method);
			if (mo != null && StringUtils.hasText(mo.getDescription())) {
				return mo.getDescription();
			}
			return method.getName();
		}
	}

	/**
	 * Reads <code>MBeanParameterInfo from the ManagedOperationParameter
	 * attributes attached to a method. Returns an empty array of <code>MBeanParameterInfo
	 * if no attributes are found.
	 */
	protected MBeanParameterInfo[] getOperationParameters(Method method, String beanKey) {
		ManagedOperationParameter[] params = this.attributeSource.getManagedOperationParameters(method);
		if (params == null || params.length == 0) {
			return new MBeanParameterInfo[0];
		}

		MBeanParameterInfo[] parameterInfo = new MBeanParameterInfo[params.length];
		Class[] methodParameters = method.getParameterTypes();

		for (int i = 0; i < params.length; i++) {
			ManagedOperationParameter param = params[i];
			parameterInfo[i] =
					new MBeanParameterInfo(param.getName(), methodParameters[i].getName(), param.getDescription());
		}

		return parameterInfo;
	}

	/**
	 * Reads the {@link ManagedNotification} metadata from the <code>Class of the managed resource
	 * and generates and returns the corresponding {@link ModelMBeanNotificationInfo} metadata.
	 */
	protected ModelMBeanNotificationInfo[] getNotificationInfo(Object managedBean, String beanKey) {
		ManagedNotification[] notificationAttributes =
				this.attributeSource.getManagedNotifications(getClassToExpose(managedBean));
		ModelMBeanNotificationInfo[] notificationInfos =
				new ModelMBeanNotificationInfo[notificationAttributes.length];

		for (int i = 0; i < notificationAttributes.length; i++) {
			ManagedNotification attribute = notificationAttributes[i];
			notificationInfos[i] = JmxMetadataUtils.convertToModelMBeanNotificationInfo(attribute);
		}

		return notificationInfos;
	}

	/**
	 * Adds descriptor fields from the <code>ManagedResource attribute
	 * to the MBean descriptor. Specifically, adds the <code>currencyTimeLimit,
	 * <code>persistPolicy, persistPeriod, persistLocation
	 * and <code>persistName descriptor fields if they are present in the metadata.
	 */
	protected void populateMBeanDescriptor(Descriptor desc, Object managedBean, String beanKey) {
		ManagedResource mr = this.attributeSource.getManagedResource(getClassToExpose(managedBean));
		if (mr == null) {
			throw new InvalidMetadataException(
					"No ManagedResource attribute found for class: " + getClassToExpose(managedBean));
		}

		applyCurrencyTimeLimit(desc, mr.getCurrencyTimeLimit());

		if (mr.isLog()) {
			desc.setField(FIELD_LOG, "true");
		}
		if (StringUtils.hasLength(mr.getLogFile())) {
			desc.setField(FIELD_LOG_FILE, mr.getLogFile());
		}

		if (StringUtils.hasLength(mr.getPersistPolicy())) {
			desc.setField(FIELD_PERSIST_POLICY, mr.getPersistPolicy());
		}
		if (mr.getPersistPeriod() >= 0) {
			desc.setField(FIELD_PERSIST_PERIOD, Integer.toString(mr.getPersistPeriod()));
		}
		if (StringUtils.hasLength(mr.getPersistName())) {
			desc.setField(FIELD_PERSIST_NAME, mr.getPersistName());
		}
		if (StringUtils.hasLength(mr.getPersistLocation())) {
			desc.setField(FIELD_PERSIST_LOCATION, mr.getPersistLocation());
		}
	}

	/**
	 * Adds descriptor fields from the <code>ManagedAttribute attribute
	 * to the attribute descriptor. Specifically, adds the <code>currencyTimeLimit,
	 * <code>default, persistPolicy and persistPeriod
	 * descriptor fields if they are present in the metadata.
	 */
	protected void populateAttributeDescriptor(Descriptor desc, Method getter, Method setter, String beanKey) {
		ManagedAttribute gma =
				(getter == null) ? ManagedAttribute.EMPTY : this.attributeSource.getManagedAttribute(getter);
		ManagedAttribute sma =
				(setter == null) ? ManagedAttribute.EMPTY : this.attributeSource.getManagedAttribute(setter);

		applyCurrencyTimeLimit(desc, resolveIntDescriptor(gma.getCurrencyTimeLimit(), sma.getCurrencyTimeLimit()));

		Object defaultValue = resolveObjectDescriptor(gma.getDefaultValue(), sma.getDefaultValue());
		desc.setField(FIELD_DEFAULT, defaultValue);

		String persistPolicy = resolveStringDescriptor(gma.getPersistPolicy(), sma.getPersistPolicy());
		if (StringUtils.hasLength(persistPolicy)) {
			desc.setField(FIELD_PERSIST_POLICY, persistPolicy);
		}
		int persistPeriod = resolveIntDescriptor(gma.getPersistPeriod(), sma.getPersistPeriod());
		if (persistPeriod >= 0) {
			desc.setField(FIELD_PERSIST_PERIOD, Integer.toString(persistPeriod));
		}
	}

	/**
	 * Adds descriptor fields from the <code>ManagedAttribute attribute
	 * to the attribute descriptor. Specifically, adds the <code>currencyTimeLimit
	 * descriptor field if it is present in the metadata.
	 */
	protected void populateOperationDescriptor(Descriptor desc, Method method, String beanKey) {
		ManagedOperation mo = this.attributeSource.getManagedOperation(method);
		if (mo != null) {
			applyCurrencyTimeLimit(desc, mo.getCurrencyTimeLimit());
		}
	}

	/**
	 * Determines which of two <code>int values should be used as the value
	 * for an attribute descriptor. In general, only the getter or the setter will
	 * be have a non-negative value so we use that value. In the event that both values
	 * are non-negative, we use the greater of the two. This method can be used to
	 * resolve any <code>int valued descriptor where there are two possible values.
	 * @param getter the int value associated with the getter for this attribute
	 * @param setter the int associated with the setter for this attribute
	 */
	private int resolveIntDescriptor(int getter, int setter) {
		return (getter >= setter ? getter : setter);
	}

	/**
	 * Locates the value of a descriptor based on values attached
	 * to both the getter and setter methods. If both have values
	 * supplied then the value attached to the getter is preferred.
	 * @param getter the Object value associated with the get method
	 * @param setter the Object value associated with the set method
	 * @return the appropriate Object to use as the value for the descriptor
	 */
	private Object resolveObjectDescriptor(Object getter, Object setter) {
		return (getter != null ? getter : setter);
	}

	/**
	 * Locates the value of a descriptor based on values attached
	 * to both the getter and setter methods. If both have values
	 * supplied then the value attached to the getter is preferred.
	 * The supplied default value is used to check to see if the value
	 * associated with the getter has changed from the default.
	 * @param getter the String value associated with the get method
	 * @param setter the String value associated with the set method
	 * @return the appropriate String to use as the value for the descriptor
	 */
	private String resolveStringDescriptor(String getter, String setter) {
		return (StringUtils.hasLength(getter) ? getter : setter);
	}

}

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