/*
 * Copyright 2002-2018 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.jndi;

import javax.naming.NamingException;

import org.springframework.beans.factory.InitializingBean;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;

Convenient superclass for JNDI-based service locators,
providing configurable lookup of a specific JNDI resource.
Exposes a "jndiName" property. This may or may not include the "java:comp/env/" prefix expected by Java EE applications when accessing a locally mapped (Environmental Naming Context) resource. If it doesn't, the "java:comp/env/" prefix will be prepended if the "resourceRef" property is true (the default is false) and no other scheme
(e.g. "java:") is given.
Subclasses may invoke the lookup() method whenever it is appropriate. Some classes might do this on initialization, while others might do it on demand. The latter strategy is more flexible in that it allows for initialization of the locator before the JNDI object is available. 
Author:
Juergen Hoeller
See Also:
setJndiName
JndiAccessor.setJndiTemplate
JndiAccessor.setJndiEnvironment
JndiLocatorSupport.setResourceRef
lookup()
Since:
1.1/**
 * Convenient superclass for JNDI-based service locators,
 * providing configurable lookup of a specific JNDI resource.
 *
 * <p>Exposes a {@link #setJndiName "jndiName"} property. This may or may not
 * include the "java:comp/env/" prefix expected by Java EE applications when
 * accessing a locally mapped (Environmental Naming Context) resource. If it
 * doesn't, the "java:comp/env/" prefix will be prepended if the "resourceRef"
 * property is true (the default is <strong>false</strong>) and no other scheme
 * (e.g. "java:") is given.
 *
 * <p>Subclasses may invoke the {@link #lookup()} method whenever it is appropriate.
 * Some classes might do this on initialization, while others might do it
 * on demand. The latter strategy is more flexible in that it allows for
 * initialization of the locator before the JNDI object is available.
 *
 * @author Juergen Hoeller
 * @since 1.1
 * @see #setJndiName
 * @see #setJndiTemplate
 * @see #setJndiEnvironment
 * @see #setResourceRef
 * @see #lookup()
 */
public abstract class JndiObjectLocator extends JndiLocatorSupport implements InitializingBean {

	@Nullable
	private String jndiName;

	@Nullable
	private Class<?> expectedType;


	
Specify the JNDI name to look up. If it doesn't begin with "java:comp/env/"
this prefix is added automatically if "resourceRef" is set to "true".
Params:
jndiName – the JNDI name to look up
See Also:
JndiLocatorSupport.setResourceRef/**
	 * Specify the JNDI name to look up. If it doesn't begin with "java:comp/env/"
	 * this prefix is added automatically if "resourceRef" is set to "true".
	 * @param jndiName the JNDI name to look up
	 * @see #setResourceRef
	 */
	public void setJndiName(@Nullable String jndiName) {
		this.jndiName = jndiName;
	}

	
Return the JNDI name to look up.
/**
	 * Return the JNDI name to look up.
	 */
	@Nullable
	public String getJndiName() {
		return this.jndiName;
	}

	
Specify the type that the located JNDI object is supposed
to be assignable to, if any.
/**
	 * Specify the type that the located JNDI object is supposed
	 * to be assignable to, if any.
	 */
	public void setExpectedType(@Nullable Class<?> expectedType) {
		this.expectedType = expectedType;
	}

	
Return the type that the located JNDI object is supposed
to be assignable to, if any.
/**
	 * Return the type that the located JNDI object is supposed
	 * to be assignable to, if any.
	 */
	@Nullable
	public Class<?> getExpectedType() {
		return this.expectedType;
	}

	@Override
	public void afterPropertiesSet() throws IllegalArgumentException, NamingException {
		if (!StringUtils.hasLength(getJndiName())) {
			throw new IllegalArgumentException("Property 'jndiName' is required");
		}
	}


	
Perform the actual JNDI lookup for this locator's target resource.
Throws:
NamingException – if the JNDI lookup failed or if the
located JNDI object is not assignable to the expected type
See Also:
setJndiName
setExpectedType
JndiLocatorSupport.lookup(String, Class<Object>)
Returns:
the located target object/**
	 * Perform the actual JNDI lookup for this locator's target resource.
	 * @return the located target object
	 * @throws NamingException if the JNDI lookup failed or if the
	 * located JNDI object is not assignable to the expected type
	 * @see #setJndiName
	 * @see #setExpectedType
	 * @see #lookup(String, Class)
	 */
	protected Object lookup() throws NamingException {
		String jndiName = getJndiName();
		Assert.state(jndiName != null, "No JNDI name specified");
		return lookup(jndiName, getExpectedType());
	}

}