/*
 * 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
 *
 *      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 javax.naming.InitialContext;
import javax.naming.NamingException;

import org.springframework.core.SpringProperties;
import org.springframework.lang.Nullable;

JndiLocatorSupport subclass with public lookup methods, for convenient use as a delegate. 
Author:
Juergen Hoeller
Since:
3.0.1/**
 * {@link JndiLocatorSupport} subclass with public lookup methods,
 * for convenient use as a delegate.
 *
 * @author Juergen Hoeller
 * @since 3.0.1
 */
public class JndiLocatorDelegate extends JndiLocatorSupport {

	
System property that instructs Spring to ignore a default JNDI environment, i.e. to always return false from isDefaultJndiEnvironmentAvailable(). 
The default is "false", allowing for regular default JNDI access e.g. in JndiPropertySource. Switching this flag to true is an optimization for scenarios where nothing is ever to be found for such JNDI fallback searches to begin with, avoiding the repeated JNDI lookup overhead. 
Note that this flag just affects JNDI fallback searches, not explicitly configured JNDI lookups such as for a DataSource or some other environment resource. The flag literally just affects code which attempts JNDI searches based on the JndiLocatorDelegate.isDefaultJndiEnvironmentAvailable() check: in particular, StandardServletEnvironment and StandardPortletEnvironment. 
See Also:
isDefaultJndiEnvironmentAvailable()
JndiPropertySource
Since:
4.3/**
	 * System property that instructs Spring to ignore a default JNDI environment, i.e.
	 * to always return {@code false} from {@link #isDefaultJndiEnvironmentAvailable()}.
	 * <p>The default is "false", allowing for regular default JNDI access e.g. in
	 * {@link JndiPropertySource}. Switching this flag to {@code true} is an optimization
	 * for scenarios where nothing is ever to be found for such JNDI fallback searches
	 * to begin with, avoiding the repeated JNDI lookup overhead.
	 * <p>Note that this flag just affects JNDI fallback searches, not explicitly configured
	 * JNDI lookups such as for a {@code DataSource} or some other environment resource.
	 * The flag literally just affects code which attempts JNDI searches based on the
	 * {@code JndiLocatorDelegate.isDefaultJndiEnvironmentAvailable()} check: in particular,
	 * {@code StandardServletEnvironment} and {@code StandardPortletEnvironment}.
	 * @since 4.3
	 * @see #isDefaultJndiEnvironmentAvailable()
	 * @see JndiPropertySource
	 */
	public static final String IGNORE_JNDI_PROPERTY_NAME = "spring.jndi.ignore";


	private static final boolean shouldIgnoreDefaultJndiEnvironment =
			SpringProperties.getFlag(IGNORE_JNDI_PROPERTY_NAME);


	@Override
	public Object lookup(String jndiName) throws NamingException {
		return super.lookup(jndiName);
	}

	@Override
	public <T> T lookup(String jndiName, @Nullable Class<T> requiredType) throws NamingException {
		return super.lookup(jndiName, requiredType);
	}


	
Configure a JndiLocatorDelegate with its "resourceRef" property set to true, meaning that all names will be prefixed with "java:comp/env/". 
See Also:
JndiLocatorSupport.setResourceRef/**
	 * Configure a {@code JndiLocatorDelegate} with its "resourceRef" property set to
	 * {@code true}, meaning that all names will be prefixed with "java:comp/env/".
	 * @see #setResourceRef
	 */
	public static JndiLocatorDelegate createDefaultResourceRefLocator() {
		JndiLocatorDelegate jndiLocator = new JndiLocatorDelegate();
		jndiLocator.setResourceRef(true);
		return jndiLocator;
	}

	
Check whether a default JNDI environment, as in a Java EE environment,
is available on this JVM.
Returns:
true if a default InitialContext can be used, false if not/**
	 * Check whether a default JNDI environment, as in a Java EE environment,
	 * is available on this JVM.
	 * @return {@code true} if a default InitialContext can be used,
	 * {@code false} if not
	 */
	public static boolean isDefaultJndiEnvironmentAvailable() {
		if (shouldIgnoreDefaultJndiEnvironment) {
			return false;
		}
		try {
			new InitialContext().getEnvironment();
			return true;
		}
		catch (Throwable ex) {
			return false;
		}
	}

}