/*
* Copyright 2002-2016 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.context.support;
import java.lang.management.ManagementFactory;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.Set;
import javax.management.MBeanServer;
import javax.management.ObjectName;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ApplicationContextException;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;
/**
* Adapter for live beans view exposure, building a snapshot of current beans
* and their dependencies from either a local {@code ApplicationContext} (with a
* local {@code LiveBeansView} bean definition) or all registered ApplicationContexts
* (driven by the {@value #MBEAN_DOMAIN_PROPERTY_NAME} environment property).
*
* <p>Note: This feature is still in beta and primarily designed for use with
* Spring Tool Suite 3.1 and higher.
*
* @author Juergen Hoeller
* @author Stephane Nicoll
* @since 3.2
* @see #getSnapshotAsJson()
* @see org.springframework.web.context.support.LiveBeansViewServlet
*/
public class LiveBeansView implements LiveBeansViewMBean, ApplicationContextAware {
public static final String MBEAN_DOMAIN_PROPERTY_NAME = "spring.liveBeansView.mbeanDomain";
public static final String MBEAN_APPLICATION_KEY = "application";
private static final Set<ConfigurableApplicationContext> applicationContexts =
new LinkedHashSet<>();
private static String applicationName;
static void registerApplicationContext(ConfigurableApplicationContext applicationContext) {
String mbeanDomain = applicationContext.getEnvironment().getProperty(MBEAN_DOMAIN_PROPERTY_NAME);
if (mbeanDomain != null) {
synchronized (applicationContexts) {
if (applicationContexts.isEmpty()) {
try {
MBeanServer server = ManagementFactory.getPlatformMBeanServer();
applicationName = applicationContext.getApplicationName();
server.registerMBean(new LiveBeansView(),
new ObjectName(mbeanDomain, MBEAN_APPLICATION_KEY, applicationName));
}
catch (Throwable ex) {
throw new ApplicationContextException("Failed to register LiveBeansView MBean", ex);
}
}
applicationContexts.add(applicationContext);
}
}
}
static void unregisterApplicationContext(ConfigurableApplicationContext applicationContext) {
synchronized (applicationContexts) {
if (applicationContexts.remove(applicationContext) && applicationContexts.isEmpty()) {
try {
MBeanServer server = ManagementFactory.getPlatformMBeanServer();
String mbeanDomain = applicationContext.getEnvironment().getProperty(MBEAN_DOMAIN_PROPERTY_NAME);
server.unregisterMBean(new ObjectName(mbeanDomain, MBEAN_APPLICATION_KEY, applicationName));
}
catch (Throwable ex) {
throw new ApplicationContextException("Failed to unregister LiveBeansView MBean", ex);
}
finally {
applicationName = null;
}
}
}
}
private ConfigurableApplicationContext applicationContext;
@Override
public void setApplicationContext(ApplicationContext applicationContext) {
Assert.isTrue(applicationContext instanceof ConfigurableApplicationContext,
"ApplicationContext does not implement ConfigurableApplicationContext");
this.applicationContext = (ConfigurableApplicationContext) applicationContext;
}
/**
* Generate a JSON snapshot of current beans and their dependencies,
* finding all active ApplicationContexts through {@link #findApplicationContexts()},
* then delegating to {@link #generateJson(java.util.Set)}.
*/
@Override
public String getSnapshotAsJson() {
Set<ConfigurableApplicationContext> contexts;
if (this.applicationContext != null) {
contexts = Collections.singleton(this.applicationContext);
}
else {
contexts = findApplicationContexts();
}
return generateJson(contexts);
}
/**
* Find all applicable ApplicationContexts for the current application.
* <p>Called if no specific ApplicationContext has been set for this LiveBeansView.
* @return the set of ApplicationContexts
*/
protected Set<ConfigurableApplicationContext> findApplicationContexts() {
synchronized (applicationContexts) {
return new LinkedHashSet<>(applicationContexts);
}
}
/**
* Actually generate a JSON snapshot of the beans in the given ApplicationContexts.
* <p>This implementation doesn't use any JSON parsing libraries in order to avoid
* third-party library dependencies. It produces an array of context description
* objects, each containing a context and parent attribute as well as a beans
* attribute with nested bean description objects. Each bean object contains a
* bean, scope, type and resource attribute, as well as a dependencies attribute
* with a nested array of bean names that the present bean depends on.
* @param contexts the set of ApplicationContexts
* @return the JSON document
*/
protected String generateJson(Set<ConfigurableApplicationContext> contexts) {
StringBuilder result = new StringBuilder("[\n");
for (Iterator<ConfigurableApplicationContext> it = contexts.iterator(); it.hasNext();) {
ConfigurableApplicationContext context = it.next();
result.append("{\n\"context\": \"").append(context.getId()).append("\",\n");
if (context.getParent() != null) {
result.append("\"parent\": \"").append(context.getParent().getId()).append("\",\n");
}
else {
result.append("\"parent\": null,\n");
}
result.append("\"beans\": [\n");
ConfigurableListableBeanFactory bf = context.getBeanFactory();
String[] beanNames = bf.getBeanDefinitionNames();
boolean elementAppended = false;
for (String beanName : beanNames) {
BeanDefinition bd = bf.getBeanDefinition(beanName);
if (isBeanEligible(beanName, bd, bf)) {
if (elementAppended) {
result.append(",\n");
}
result.append("{\n\"bean\": \"").append(beanName).append("\",\n");
result.append("\"aliases\": ");
appendArray(result, bf.getAliases(beanName));
result.append(",\n");
String scope = bd.getScope();
if (!StringUtils.hasText(scope)) {
scope = BeanDefinition.SCOPE_SINGLETON;
}
result.append("\"scope\": \"").append(scope).append("\",\n");
Class<?> beanType = bf.getType(beanName);
if (beanType != null) {
result.append("\"type\": \"").append(beanType.getName()).append("\",\n");
}
else {
result.append("\"type\": null,\n");
}
result.append("\"resource\": \"").append(getEscapedResourceDescription(bd)).append("\",\n");
result.append("\"dependencies\": ");
appendArray(result, bf.getDependenciesForBean(beanName));
result.append("\n}");
elementAppended = true;
}
}
result.append("]\n");
result.append("}");
if (it.hasNext()) {
result.append(",\n");
}
}
result.append("]");
return result.toString();
}
/**
* Determine whether the specified bean is eligible for inclusion in the
* LiveBeansView JSON snapshot.
* @param beanName the name of the bean
* @param bd the corresponding bean definition
* @param bf the containing bean factory
* @return {@code true} if the bean is to be included; {@code false} otherwise
*/
protected boolean isBeanEligible(String beanName, BeanDefinition bd, ConfigurableBeanFactory bf) {
return (bd.getRole() != BeanDefinition.ROLE_INFRASTRUCTURE &&
(!bd.isLazyInit() || bf.containsSingleton(beanName)));
}
/**
* Determine a resource description for the given bean definition and
* apply basic JSON escaping (backslashes, double quotes) to it.
* @param bd the bean definition to build the resource description for
* @return the JSON-escaped resource description
*/
protected String getEscapedResourceDescription(BeanDefinition bd) {
String resourceDescription = bd.getResourceDescription();
if (resourceDescription == null) {
return null;
}
StringBuilder result = new StringBuilder(resourceDescription.length() + 16);
for (int i = 0; i < resourceDescription.length(); i++) {
char character = resourceDescription.charAt(i);
if (character == '\\') {
result.append('/');
}
else if (character == '"') {
result.append("\\").append('"');
}
else {
result.append(character);
}
}
return result.toString();
}
private void appendArray(StringBuilder result, String[] arr) {
result.append('[');
if (arr.length > 0) {
result.append('\"');
}
result.append(StringUtils.arrayToDelimitedString(arr, "\", \""));
if (arr.length > 0) {
result.append('\"');
}
result.append(']');
}
}