https://github.com/spring-projects/spring-framework: Spring Context (Spring IO)
  • Juergen Hoeller 
/*
 * 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.jndi;

import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

import javax.naming.Context;
import javax.naming.NamingException;

import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;

import org.springframework.aop.framework.ProxyFactory;
import org.springframework.beans.SimpleTypeConverter;
import org.springframework.beans.TypeConverter;
import org.springframework.beans.TypeMismatchException;
import org.springframework.beans.factory.BeanClassLoaderAware;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;


FactoryBean that looks up a JNDI object. Exposes the object found in JNDI for bean references, e.g. for data access object's "dataSource" property in case of a DataSource. 
The typical usage will be to register this as singleton factory
(e.g. for a certain JNDI-bound DataSource) in an application context,
and give bean references to application services that need it.

The default behavior is to look up the JNDI object on startup and cache it. This can be customized through the "lookupOnStartup" and "cache" properties, using a JndiObjectTargetSource underneath. Note that you need to specify a "proxyInterface" in such a scenario, since the actual JNDI object type is not known in advance. 
Of course, bean classes in a Spring environment may lookup e.g. a DataSource
from JNDI themselves. This class simply enables central configuration of the
JNDI name, and easy switching to non-JNDI alternatives. The latter is
particularly convenient for test setups, reuse in standalone clients, etc.

Note that switching to e.g. DriverManagerDataSource is just a matter of configuration: Simply replace the definition of this FactoryBean with a DriverManagerDataSource definition! 
Author:Juergen Hoeller
See Also:
Since:22.05.2003
/**
 * {@link org.springframework.beans.factory.FactoryBean} that looks up a
 * JNDI object. Exposes the object found in JNDI for bean references,
 * e.g. for data access object's "dataSource" property in case of a
 * {@link javax.sql.DataSource}.
 *
 * <p>The typical usage will be to register this as singleton factory
 * (e.g. for a certain JNDI-bound DataSource) in an application context,
 * and give bean references to application services that need it.
 *
 * <p>The default behavior is to look up the JNDI object on startup and cache it.
 * This can be customized through the "lookupOnStartup" and "cache" properties,
 * using a {@link JndiObjectTargetSource} underneath. Note that you need to specify
 * a "proxyInterface" in such a scenario, since the actual JNDI object type is not
 * known in advance.
 *
 * <p>Of course, bean classes in a Spring environment may lookup e.g. a DataSource
 * from JNDI themselves. This class simply enables central configuration of the
 * JNDI name, and easy switching to non-JNDI alternatives. The latter is
 * particularly convenient for test setups, reuse in standalone clients, etc.
 *
 * <p>Note that switching to e.g. DriverManagerDataSource is just a matter of
 * configuration: Simply replace the definition of this FactoryBean with a
 * {@link org.springframework.jdbc.datasource.DriverManagerDataSource} definition!
 *
 * @author Juergen Hoeller
 * @since 22.05.2003
 * @see #setProxyInterface
 * @see #setLookupOnStartup
 * @see #setCache
 * @see JndiObjectTargetSource
 */
public class JndiObjectFactoryBean extends JndiObjectLocator
		implements FactoryBean<Object>, BeanFactoryAware, BeanClassLoaderAware {

	@Nullable
	private Class<?>[] proxyInterfaces;

	private boolean lookupOnStartup = true;

	private boolean cache = true;

	private boolean exposeAccessContext = false;

	@Nullable
	private Object defaultObject;

	@Nullable
	private ConfigurableBeanFactory beanFactory;

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

	@Nullable
	private Object jndiObject;


	
Specify the proxy interface to use for the JNDI object.

Typically used in conjunction with "lookupOnStartup"=false and/or "cache"=false.
Needs to be specified because the actual JNDI object type is not known
in advance in case of a lazy lookup.

See Also:
/**
	 * Specify the proxy interface to use for the JNDI object.
	 * <p>Typically used in conjunction with "lookupOnStartup"=false and/or "cache"=false.
	 * Needs to be specified because the actual JNDI object type is not known
	 * in advance in case of a lazy lookup.
	 * @see #setProxyInterfaces
	 * @see #setLookupOnStartup
	 * @see #setCache
	 */
	public void setProxyInterface(Class<?> proxyInterface) {
		this.proxyInterfaces = new Class<?>[] {proxyInterface};
	}

	
Specify multiple proxy interfaces to use for the JNDI object.

Typically used in conjunction with "lookupOnStartup"=false and/or "cache"=false.
Note that proxy interfaces will be autodetected from a specified "expectedType",
if necessary.

See Also:
/**
	 * Specify multiple proxy interfaces to use for the JNDI object.
	 * <p>Typically used in conjunction with "lookupOnStartup"=false and/or "cache"=false.
	 * Note that proxy interfaces will be autodetected from a specified "expectedType",
	 * if necessary.
	 * @see #setExpectedType
	 * @see #setLookupOnStartup
	 * @see #setCache
	 */
	public void setProxyInterfaces(Class<?>... proxyInterfaces) {
		this.proxyInterfaces = proxyInterfaces;
	}

	
Set whether to look up the JNDI object on startup. Default is "true".

Can be turned off to allow for late availability of the JNDI object.
In this case, the JNDI object will be fetched on first access.

For a lazy lookup, a proxy interface needs to be specified.

See Also:
/**
	 * Set whether to look up the JNDI object on startup. Default is "true".
	 * <p>Can be turned off to allow for late availability of the JNDI object.
	 * In this case, the JNDI object will be fetched on first access.
	 * <p>For a lazy lookup, a proxy interface needs to be specified.
	 * @see #setProxyInterface
	 * @see #setCache
	 */
	public void setLookupOnStartup(boolean lookupOnStartup) {
		this.lookupOnStartup = lookupOnStartup;
	}

	
Set whether to cache the JNDI object once it has been located.
Default is "true".

Can be turned off to allow for hot redeployment of JNDI objects.
In this case, the JNDI object will be fetched for each invocation.

For hot redeployment, a proxy interface needs to be specified.

See Also:
/**
	 * Set whether to cache the JNDI object once it has been located.
	 * Default is "true".
	 * <p>Can be turned off to allow for hot redeployment of JNDI objects.
	 * In this case, the JNDI object will be fetched for each invocation.
	 * <p>For hot redeployment, a proxy interface needs to be specified.
	 * @see #setProxyInterface
	 * @see #setLookupOnStartup
	 */
	public void setCache(boolean cache) {
		this.cache = cache;
	}

	
Set whether to expose the JNDI environment context for all access to the target
object, i.e. for all method invocations on the exposed object reference.

Default is "false", i.e. to only expose the JNDI context for object lookup.
Switch this flag to "true" in order to expose the JNDI environment (including
the authorization context) for each method invocation, as needed by WebLogic
for JNDI-obtained factories (e.g. JDBC DataSource, JMS ConnectionFactory)
with authorization requirements.

/**
	 * Set whether to expose the JNDI environment context for all access to the target
	 * object, i.e. for all method invocations on the exposed object reference.
	 * <p>Default is "false", i.e. to only expose the JNDI context for object lookup.
	 * Switch this flag to "true" in order to expose the JNDI environment (including
	 * the authorization context) for each method invocation, as needed by WebLogic
	 * for JNDI-obtained factories (e.g. JDBC DataSource, JMS ConnectionFactory)
	 * with authorization requirements.
	 */
	public void setExposeAccessContext(boolean exposeAccessContext) {
		this.exposeAccessContext = exposeAccessContext;
	}

	
Specify a default object to fall back to if the JNDI lookup fails.
Default is none.

This can be an arbitrary bean reference or literal value.
It is typically used for literal values in scenarios where the JNDI environment
might define specific config settings but those are not required to be present.

Note: This is only supported for lookup on startup. If specified together with JndiObjectLocator.setExpectedType, the specified value needs to be either of that type or convertible to it. 
See Also:
/**
	 * Specify a default object to fall back to if the JNDI lookup fails.
	 * Default is none.
	 * <p>This can be an arbitrary bean reference or literal value.
	 * It is typically used for literal values in scenarios where the JNDI environment
	 * might define specific config settings but those are not required to be present.
	 * <p>Note: This is only supported for lookup on startup.
	 * If specified together with {@link #setExpectedType}, the specified value
	 * needs to be either of that type or convertible to it.
	 * @see #setLookupOnStartup
	 * @see ConfigurableBeanFactory#getTypeConverter()
	 * @see SimpleTypeConverter
	 */
	public void setDefaultObject(Object defaultObject) {
		this.defaultObject = defaultObject;
	}

	@Override
	public void setBeanFactory(BeanFactory beanFactory) {
		if (beanFactory instanceof ConfigurableBeanFactory) {
			// Just optional - for getting a specifically configured TypeConverter if needed.
			// We'll simply fall back to a SimpleTypeConverter if no specific one available.
			this.beanFactory = (ConfigurableBeanFactory) beanFactory;
		}
	}

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


	
Look up the JNDI object and store it.

/**
	 * Look up the JNDI object and store it.
	 */
	@Override
	public void afterPropertiesSet() throws IllegalArgumentException, NamingException {
		super.afterPropertiesSet();

		if (this.proxyInterfaces != null || !this.lookupOnStartup || !this.cache || this.exposeAccessContext) {
			// We need to create a proxy for this...
			if (this.defaultObject != null) {
				throw new IllegalArgumentException(
						"'defaultObject' is not supported in combination with 'proxyInterface'");
			}
			// We need a proxy and a JndiObjectTargetSource.
			this.jndiObject = JndiObjectProxyFactory.createJndiObjectProxy(this);
		}
		else {
			if (this.defaultObject != null && getExpectedType() != null &&
					!getExpectedType().isInstance(this.defaultObject)) {
				TypeConverter converter = (this.beanFactory != null ?
						this.beanFactory.getTypeConverter() : new SimpleTypeConverter());
				try {
					this.defaultObject = converter.convertIfNecessary(this.defaultObject, getExpectedType());
				}
				catch (TypeMismatchException ex) {
					throw new IllegalArgumentException("Default object [" + this.defaultObject + "] of type [" +
							this.defaultObject.getClass().getName() + "] is not of expected type [" +
							getExpectedType().getName() + "] and cannot be converted either", ex);
				}
			}
			// Locate specified JNDI object.
			this.jndiObject = lookupWithFallback();
		}
	}

	
Lookup variant that returns the specified "defaultObject"
(if any) in case of lookup failure.

Throws:
See Also:
Returns:the located object, or the "defaultObject" as fallback
/**
	 * Lookup variant that returns the specified "defaultObject"
	 * (if any) in case of lookup failure.
	 * @return the located object, or the "defaultObject" as fallback
	 * @throws NamingException in case of lookup failure without fallback
	 * @see #setDefaultObject
	 */
	protected Object lookupWithFallback() throws NamingException {
		ClassLoader originalClassLoader = ClassUtils.overrideThreadContextClassLoader(this.beanClassLoader);
		try {
			return lookup();
		}
		catch (TypeMismatchNamingException ex) {
			// Always let TypeMismatchNamingException through -
			// we don't want to fall back to the defaultObject in this case.
			throw ex;
		}
		catch (NamingException ex) {
			if (this.defaultObject != null) {
				if (logger.isTraceEnabled()) {
					logger.trace("JNDI lookup failed - returning specified default object instead", ex);
				}
				else if (logger.isDebugEnabled()) {
					logger.debug("JNDI lookup failed - returning specified default object instead: " + ex);
				}
				return this.defaultObject;
			}
			throw ex;
		}
		finally {
			if (originalClassLoader != null) {
				Thread.currentThread().setContextClassLoader(originalClassLoader);
			}
		}
	}


	
Return the singleton JNDI object.

/**
	 * Return the singleton JNDI object.
	 */
	@Override
	@Nullable
	public Object getObject() {
		return this.jndiObject;
	}

	@Override
	public Class<?> getObjectType() {
		if (this.proxyInterfaces != null) {
			if (this.proxyInterfaces.length == 1) {
				return this.proxyInterfaces[0];
			}
			else if (this.proxyInterfaces.length > 1) {
				return createCompositeInterface(this.proxyInterfaces);
			}
		}
		if (this.jndiObject != null) {
			return this.jndiObject.getClass();
		}
		else {
			return getExpectedType();
		}
	}

	@Override
	public boolean isSingleton() {
		return true;
	}


	
Create a composite interface Class for the given interfaces,
implementing the given interfaces in one single Class.

The default implementation builds a JDK proxy class for the
given interfaces.

Params:
  • interfaces – the interfaces to merge
See Also:
Returns:the merged interface as Class
/**
	 * Create a composite interface Class for the given interfaces,
	 * implementing the given interfaces in one single Class.
	 * <p>The default implementation builds a JDK proxy class for the
	 * given interfaces.
	 * @param interfaces the interfaces to merge
	 * @return the merged interface as Class
	 * @see java.lang.reflect.Proxy#getProxyClass
	 */
	protected Class<?> createCompositeInterface(Class<?>[] interfaces) {
		return ClassUtils.createCompositeInterface(interfaces, this.beanClassLoader);
	}


	
Inner class to just introduce an AOP dependency when actually creating a proxy.

/**
	 * Inner class to just introduce an AOP dependency when actually creating a proxy.
	 */
	private static class JndiObjectProxyFactory {

		private static Object createJndiObjectProxy(JndiObjectFactoryBean jof) throws NamingException {
			// Create a JndiObjectTargetSource that mirrors the JndiObjectFactoryBean's configuration.
			JndiObjectTargetSource targetSource = new JndiObjectTargetSource();
			targetSource.setJndiTemplate(jof.getJndiTemplate());
			String jndiName = jof.getJndiName();
			Assert.state(jndiName != null, "No JNDI name specified");
			targetSource.setJndiName(jndiName);
			targetSource.setExpectedType(jof.getExpectedType());
			targetSource.setResourceRef(jof.isResourceRef());
			targetSource.setLookupOnStartup(jof.lookupOnStartup);
			targetSource.setCache(jof.cache);
			targetSource.afterPropertiesSet();

			// Create a proxy with JndiObjectFactoryBean's proxy interface and the JndiObjectTargetSource.
			ProxyFactory proxyFactory = new ProxyFactory();
			if (jof.proxyInterfaces != null) {
				proxyFactory.setInterfaces(jof.proxyInterfaces);
			}
			else {
				Class<?> targetClass = targetSource.getTargetClass();
				if (targetClass == null) {
					throw new IllegalStateException(
							"Cannot deactivate 'lookupOnStartup' without specifying a 'proxyInterface' or 'expectedType'");
				}
				Class<?>[] ifcs = ClassUtils.getAllInterfacesForClass(targetClass, jof.beanClassLoader);
				for (Class<?> ifc : ifcs) {
					if (Modifier.isPublic(ifc.getModifiers())) {
						proxyFactory.addInterface(ifc);
					}
				}
			}
			if (jof.exposeAccessContext) {
				proxyFactory.addAdvice(new JndiContextExposingInterceptor(jof.getJndiTemplate()));
			}
			proxyFactory.setTargetSource(targetSource);
			return proxyFactory.getProxy(jof.beanClassLoader);
		}
	}


	
Interceptor that exposes the JNDI context for all method invocations,
according to JndiObjectFactoryBean's "exposeAccessContext" flag.

/**
	 * Interceptor that exposes the JNDI context for all method invocations,
	 * according to JndiObjectFactoryBean's "exposeAccessContext" flag.
	 */
	private static class JndiContextExposingInterceptor implements MethodInterceptor {

		private final JndiTemplate jndiTemplate;

		public JndiContextExposingInterceptor(JndiTemplate jndiTemplate) {
			this.jndiTemplate = jndiTemplate;
		}

		@Override
		@Nullable
		public Object invoke(MethodInvocation invocation) throws Throwable {
			Context ctx = (isEligible(invocation.getMethod()) ? this.jndiTemplate.getContext() : null);
			try {
				return invocation.proceed();
			}
			finally {
				this.jndiTemplate.releaseContext(ctx);
			}
		}

		protected boolean isEligible(Method method) {
			return (Object.class != method.getDeclaringClass());
		}
	}

}