/*
 * Copyright 2002-2020 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
 *
 *      https://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.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.Map;
import java.util.Properties;

import org.springframework.beans.factory.BeanClassLoaderAware;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.lang.Nullable;
import org.springframework.util.ClassUtils;
import org.springframework.util.CollectionUtils;
import org.springframework.util.StringUtils;

Subclass of AbstractReflectiveMBeanInfoAssembler that allows for the management interface of a bean to be defined using arbitrary interfaces. Any methods or properties that are defined in those interfaces are exposed as MBean operations and attributes. 
By default, this class votes on the inclusion of each operation or attribute based on the interfaces implemented by the bean class. However, you can supply an array of interfaces via the managedInterfaces property that will be used instead. If you have multiple beans and you wish each bean to use a different set of interfaces, then you can map bean keys (that is the name used to pass the bean to the MBeanExporter) to a list of interface names using the interfaceMappings property. 
If you specify values for both interfaceMappings and managedInterfaces, Spring will attempt to find interfaces in the mappings first. If no interfaces for the bean are found, it will use the interfaces defined by managedInterfaces. 
Author:
Rob Harrop, Juergen Hoeller
See Also:
setManagedInterfaces
setInterfaceMappings
MethodNameBasedMBeanInfoAssembler
SimpleReflectiveMBeanInfoAssembler
MBeanExporter
Since:
1.2/**
 * Subclass of {@code AbstractReflectiveMBeanInfoAssembler} that allows for
 * the management interface of a bean to be defined using arbitrary interfaces.
 * Any methods or properties that are defined in those interfaces are exposed
 * as MBean operations and attributes.
 *
 * <p>By default, this class votes on the inclusion of each operation or attribute
 * based on the interfaces implemented by the bean class. However, you can supply an
 * array of interfaces via the {@code managedInterfaces} property that will be
 * used instead. If you have multiple beans and you wish each bean to use a different
 * set of interfaces, then you can map bean keys (that is the name used to pass the
 * bean to the {@code MBeanExporter}) to a list of interface names using the
 * {@code interfaceMappings} property.
 *
 * <p>If you specify values for both {@code interfaceMappings} and
 * {@code managedInterfaces}, Spring will attempt to find interfaces in the
 * mappings first. If no interfaces for the bean are found, it will use the
 * interfaces defined by {@code managedInterfaces}.
 *
 * @author Rob Harrop
 * @author Juergen Hoeller
 * @since 1.2
 * @see #setManagedInterfaces
 * @see #setInterfaceMappings
 * @see MethodNameBasedMBeanInfoAssembler
 * @see SimpleReflectiveMBeanInfoAssembler
 * @see org.springframework.jmx.export.MBeanExporter
 */
public class InterfaceBasedMBeanInfoAssembler extends AbstractConfigurableMBeanInfoAssembler
		implements BeanClassLoaderAware, InitializingBean {

	@Nullable
	private Class<?>[] managedInterfaces;

	
Mappings of bean keys to an array of classes. /** Mappings of bean keys to an array of classes. */
	@Nullable
	private Properties interfaceMappings;

	@Nullable
	private ClassLoader beanClassLoader = ClassUtils.getDefaultClassLoader();

	
Mappings of bean keys to an array of classes. /** Mappings of bean keys to an array of classes. */
	@Nullable
	private Map<String, Class<?>[]> resolvedInterfaceMappings;


	
Set the array of interfaces to use for creating the management info. These interfaces will be used for a bean if no entry corresponding to that bean is found in the interfaceMappings property. 
Params:
managedInterfaces – an array of classes indicating the interfaces to use.
Each entry MUST be an interface.
See Also:
setInterfaceMappings/**
	 * Set the array of interfaces to use for creating the management info.
	 * These interfaces will be used for a bean if no entry corresponding to
	 * that bean is found in the {@code interfaceMappings} property.
	 * @param managedInterfaces an array of classes indicating the interfaces to use.
	 * Each entry <strong>MUST</strong> be an interface.
	 * @see #setInterfaceMappings
	 */
	public void setManagedInterfaces(@Nullable Class<?>... managedInterfaces) {
		if (managedInterfaces != null) {
			for (Class<?> ifc : managedInterfaces) {
				if (!ifc.isInterface()) {
					throw new IllegalArgumentException(
							"Management interface [" + ifc.getName() + "] is not an interface");
				}
			}
		}
		this.managedInterfaces = managedInterfaces;
	}

	
Set the mappings of bean keys to a comma-separated list of interface names.
The property key should match the bean key and the property value should match
the list of interface names. When searching for interfaces for a bean, Spring
will check these mappings first.
Params:
mappings – the mappings of bean keys to interface names/**
	 * Set the mappings of bean keys to a comma-separated list of interface names.
	 * <p>The property key should match the bean key and the property value should match
	 * the list of interface names. When searching for interfaces for a bean, Spring
	 * will check these mappings first.
	 * @param mappings the mappings of bean keys to interface names
	 */
	public void setInterfaceMappings(@Nullable Properties mappings) {
		this.interfaceMappings = mappings;
	}

	@Override
	public void setBeanClassLoader(@Nullable ClassLoader beanClassLoader) {
		this.beanClassLoader = beanClassLoader;
	}


	@Override
	public void afterPropertiesSet() {
		if (this.interfaceMappings != null) {
			this.resolvedInterfaceMappings = resolveInterfaceMappings(this.interfaceMappings);
		}
	}

	
Resolve the given interface mappings, turning class names into Class objects.
Params:
mappings – the specified interface mappings
Returns:
the resolved interface mappings (with Class objects as values)/**
	 * Resolve the given interface mappings, turning class names into Class objects.
	 * @param mappings the specified interface mappings
	 * @return the resolved interface mappings (with Class objects as values)
	 */
	private Map<String, Class<?>[]> resolveInterfaceMappings(Properties mappings) {
		Map<String, Class<?>[]> resolvedMappings = CollectionUtils.newHashMap(mappings.size());
		for (Enumeration<?> en = mappings.propertyNames(); en.hasMoreElements();) {
			String beanKey = (String) en.nextElement();
			String[] classNames = StringUtils.commaDelimitedListToStringArray(mappings.getProperty(beanKey));
			Class<?>[] classes = resolveClassNames(classNames, beanKey);
			resolvedMappings.put(beanKey, classes);
		}
		return resolvedMappings;
	}

	
Resolve the given class names into Class objects.
Params:
classNames – the class names to resolve
beanKey – the bean key that the class names are associated with
Returns:
the resolved Class/**
	 * Resolve the given class names into Class objects.
	 * @param classNames the class names to resolve
	 * @param beanKey the bean key that the class names are associated with
	 * @return the resolved Class
	 */
	private Class<?>[] resolveClassNames(String[] classNames, String beanKey) {
		Class<?>[] classes = new Class<?>[classNames.length];
		for (int x = 0; x < classes.length; x++) {
			Class<?> cls = ClassUtils.resolveClassName(classNames[x].trim(), this.beanClassLoader);
			if (!cls.isInterface()) {
				throw new IllegalArgumentException(
						"Class [" + classNames[x] + "] mapped to bean key [" + beanKey + "] is no interface");
			}
			classes[x] = cls;
		}
		return classes;
	}


	
Check to see if the Method is declared in one of the configured interfaces and that it is public. 
Params:
method – the accessor Method.
beanKey – the key associated with the MBean in the beans Map.
Returns:
true if the Method is declared in one of the configured interfaces, otherwise false./**
	 * Check to see if the {@code Method} is declared in
	 * one of the configured interfaces and that it is public.
	 * @param method the accessor {@code Method}.
	 * @param beanKey the key associated with the MBean in the
	 * {@code beans} {@code Map}.
	 * @return {@code true} if the {@code Method} is declared in one of the
	 * configured interfaces, otherwise {@code false}.
	 */
	@Override
	protected boolean includeReadAttribute(Method method, String beanKey) {
		return isPublicInInterface(method, beanKey);
	}

	
Check to see if the Method is declared in one of the configured interfaces and that it is public. 
Params:
method – the mutator Method.
beanKey – the key associated with the MBean in the beans Map.
Returns:
true if the Method is declared in one of the configured interfaces, otherwise false./**
	 * Check to see if the {@code Method} is declared in
	 * one of the configured interfaces and that it is public.
	 * @param method the mutator {@code Method}.
	 * @param beanKey the key associated with the MBean in the
	 * {@code beans} {@code Map}.
	 * @return {@code true} if the {@code Method} is declared in one of the
	 * configured interfaces, otherwise {@code false}.
	 */
	@Override
	protected boolean includeWriteAttribute(Method method, String beanKey) {
		return isPublicInInterface(method, beanKey);
	}

	
Check to see if the Method is declared in one of the configured interfaces and that it is public. 
Params:
method – the operation Method.
beanKey – the key associated with the MBean in the beans Map.
Returns:
true if the Method is declared in one of the configured interfaces, otherwise false./**
	 * Check to see if the {@code Method} is declared in
	 * one of the configured interfaces and that it is public.
	 * @param method the operation {@code Method}.
	 * @param beanKey the key associated with the MBean in the
	 * {@code beans} {@code Map}.
	 * @return {@code true} if the {@code Method} is declared in one of the
	 * configured interfaces, otherwise {@code false}.
	 */
	@Override
	protected boolean includeOperation(Method method, String beanKey) {
		return isPublicInInterface(method, beanKey);
	}

	
Check to see if the Method is both public and declared in one of the configured interfaces. 
Params:
method – the Method to check.
beanKey – the key associated with the MBean in the beans map
Returns:
true if the Method is declared in one of the configured interfaces and is public, otherwise false./**
	 * Check to see if the {@code Method} is both public and declared in
	 * one of the configured interfaces.
	 * @param method the {@code Method} to check.
	 * @param beanKey the key associated with the MBean in the beans map
	 * @return {@code true} if the {@code Method} is declared in one of the
	 * configured interfaces and is public, otherwise {@code false}.
	 */
	private boolean isPublicInInterface(Method method, String beanKey) {
		return Modifier.isPublic(method.getModifiers()) && isDeclaredInInterface(method, beanKey);
	}

	
Checks to see if the given method is declared in a managed
interface for the given bean.
/**
	 * Checks to see if the given method is declared in a managed
	 * interface for the given bean.
	 */
	private boolean isDeclaredInInterface(Method method, String beanKey) {
		Class<?>[] ifaces = null;

		if (this.resolvedInterfaceMappings != null) {
			ifaces = this.resolvedInterfaceMappings.get(beanKey);
		}

		if (ifaces == null) {
			ifaces = this.managedInterfaces;
			if (ifaces == null) {
				ifaces = ClassUtils.getAllInterfacesForClass(method.getDeclaringClass());
			}
		}

		for (Class<?> ifc : ifaces) {
			for (Method ifcMethod : ifc.getMethods()) {
				if (ifcMethod.getName().equals(method.getName()) &&
						ifcMethod.getParameterCount() == method.getParameterCount() &&
						Arrays.equals(ifcMethod.getParameterTypes(), method.getParameterTypes())) {
					return true;
				}
			}
		}

		return false;
	}

}