/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.jmeter.protocol.java.sampler;

import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

import org.apache.jmeter.config.Arguments;
import org.apache.jmeter.engine.event.LoopIterationEvent;
import org.apache.jmeter.samplers.AbstractSampler;
import org.apache.jmeter.samplers.Entry;
import org.apache.jmeter.samplers.SampleResult;
import org.apache.jmeter.testelement.TestElement;
import org.apache.jmeter.testelement.TestListener;
import org.apache.jmeter.testelement.property.TestElementProperty;
import org.apache.jorphan.logging.LoggingManager;
import org.apache.log.Logger;

/**
 * A sampler for executing custom Java code in each sample. See
 * {@link JavaSamplerClient} and {@link AbstractJavaSamplerClient} for
 * information on writing Java code to be executed by this sampler.
 *
 */
public class JavaSampler extends AbstractSampler implements TestListener {

	private static final Logger log = LoggingManager.getLoggerForClass();

	private static final long serialVersionUID = 232L; // Remember to change this when the class changes ...

	/**
	 * Property key representing the classname of the JavaSamplerClient to user.
	 */
	public static final String CLASSNAME = "classname";

	/**
	 * Property key representing the arguments for the JavaSamplerClient.
	 */
	public static final String ARGUMENTS = "arguments";

	/**
	 * The JavaSamplerClient instance used by this sampler to actually perform
	 * the sample.
	 */
	private transient JavaSamplerClient javaClient = null;

	/**
	 * The JavaSamplerContext instance used by this sampler to hold information
	 * related to the test run, such as the parameters specified for the sampler
	 * client.
	 */
	private transient JavaSamplerContext context = null;

	/**
	 * Set used to register all active JavaSamplers. This is used so that the
	 * samplers can be notified when the test ends.
	 */
	private static final Set allSamplers = new HashSet();

	/**
	 * Create a JavaSampler.
	 */
	public JavaSampler() {
		setArguments(new Arguments());
		synchronized (allSamplers) {
			allSamplers.add(this);
		}
	}

	/**
	 * Set the arguments (parameters) for the JavaSamplerClient to be executed
	 * with.
	 * 
	 * @param args
	 *            the new arguments. These replace any existing arguments.
	 */
	public void setArguments(Arguments args) {
		setProperty(new TestElementProperty(ARGUMENTS, args));
	}

	/**
	 * Get the arguments (parameters) for the JavaSamplerClient to be executed
	 * with.
	 * 
	 * @return the arguments
	 */
	public Arguments getArguments() {
		return (Arguments) getProperty(ARGUMENTS).getObjectValue();
	}

	/**
	 * Releases Java Client.
	 */
	private void releaseJavaClient() {
		if (javaClient != null) {
			javaClient.teardownTest(context);
		}
		javaClient = null;
		context = null;
	}

	/**
	 * Sets the Classname attribute of the JavaConfig object
	 * 
	 * @param classname
	 *            the new Classname value
	 */
	public void setClassname(String classname) {
		setProperty(CLASSNAME, classname);
	}

	/**
	 * Gets the Classname attribute of the JavaConfig object
	 * 
	 * @return the Classname value
	 */
	public String getClassname() {
		return getPropertyAsString(CLASSNAME);
	}

	/**
	 * Performs a test sample.
	 * 
	 * The <code>sample()</code> method retrieves the reference to the Java
	 * client and calls its <code>runTest()</code> method.
	 * 
	 * @see JavaSamplerClient#runTest(JavaSamplerContext)
	 * 
	 * @param entry
	 *            the Entry for this sample
	 * @return test SampleResult
	 */
	public SampleResult sample(Entry entry) {
		Arguments args = getArguments();
		args.addArgument(TestElement.NAME, getName()); // Allow Sampler access
														// to test element name
		context = new JavaSamplerContext(args);
		if (javaClient == null) {
			log.debug(whoAmI() + "Creating Java Client");
			createJavaClient();
			javaClient.setupTest(context);
		}
        
        SampleResult result = createJavaClient().runTest(context);
        
        // Only set the default label if it has not been set
        if (result != null && result.getSampleLabel().length() == 0) {
            result.setSampleLabel(getName());
        }

        return result;
    }

	/**
	 * Returns reference to <code>JavaSamplerClient</code>.
	 * 
	 * The <code>createJavaClient()</code> method uses reflection to create an
	 * instance of the specified Java protocol client. If the class can not be
	 * found, the method returns a reference to <code>this</code> object.
	 * 
	 * @return JavaSamplerClient reference.
	 */
	private JavaSamplerClient createJavaClient() {
		if (javaClient == null) {
			try {
				Class javaClass = Class.forName(getClassname().trim(), false, Thread.currentThread()
						.getContextClassLoader());
				javaClient = (JavaSamplerClient) javaClass.newInstance();
				context = new JavaSamplerContext(getArguments());

				if (log.isDebugEnabled()) {
					log.debug(whoAmI() + "\tCreated:\t" + getClassname() + "@"
							+ Integer.toHexString(javaClient.hashCode()));
				}
			} catch (Exception e) {
				log.error(whoAmI() + "\tException creating: " + getClassname(), e);
				javaClient = new ErrorSamplerClient();
			}
		}
		return javaClient;
	}

	/**
	 * Retrieves reference to JavaSamplerClient.
	 * 
	 * Convience method used to check for null reference without actually
	 * creating a JavaSamplerClient
	 * 
	 * @return reference to JavaSamplerClient NOTUSED private JavaSamplerClient
	 *         retrieveJavaClient() { return javaClient; }
	 */

	/**
	 * Generate a String identifier of this instance for debugging purposes.
	 * 
	 * @return a String identifier for this sampler instance
	 */
	private String whoAmI() {
		StringBuffer sb = new StringBuffer();
		sb.append(Thread.currentThread().getName());
		sb.append("@");
		sb.append(Integer.toHexString(hashCode()));
		sb.append("-");
		sb.append(getName());
		return sb.toString();
	}

	// TestListener implementation
	/* Implements TestListener.testStarted() */
	public void testStarted() {
		log.debug(whoAmI() + "\ttestStarted");
	}

	/* Implements TestListener.testStarted(String) */
	public void testStarted(String host) {
		log.debug(whoAmI() + "\ttestStarted(" + host + ")");
	}

	/**
	 * Method called at the end of the test. This is called only on one instance
	 * of JavaSampler. This method will loop through all of the other
	 * JavaSamplers which have been registered (automatically in the
	 * constructor) and notify them that the test has ended, allowing the
	 * JavaSamplerClients to cleanup.
	 */
	public void testEnded() {
		log.debug(whoAmI() + "\ttestEnded");
		synchronized (allSamplers) {
			Iterator i = allSamplers.iterator();
			while (i.hasNext()) {
				JavaSampler sampler = (JavaSampler) i.next();
				sampler.releaseJavaClient();
				i.remove();
			}
		}
	}

	/* Implements TestListener.testEnded(String) */
	public void testEnded(String host) {
		testEnded();
	}

	/* Implements TestListener.testIterationStart(LoopIterationEvent) */
	public void testIterationStart(LoopIterationEvent event) {
	}

	/**
	 * A {@link JavaSamplerClient} implementation used for error handling. If an
	 * error occurs while creating the real JavaSamplerClient object, it is
	 * replaced with an instance of this class. Each time a sample occurs with
	 * this class, the result is marked as a failure so the user can see that
	 * the test failed.
	 */
	class ErrorSamplerClient extends AbstractJavaSamplerClient {
		/**
		 * Return SampleResult with data on error.
		 * 
		 * @see JavaSamplerClient#runTest(JavaSamplerContext)
		 */
		public SampleResult runTest(JavaSamplerContext p_context) {
			log.debug(whoAmI() + "\trunTest");
			Thread.yield();
			SampleResult results = new SampleResult();
			results.setSuccessful(false);
			results.setResponseData(("Class not found: " + getClassname()).getBytes());
			results.setSampleLabel("ERROR: " + getClassname());
			return results;
		}
	}
}
