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/*
 * Copyright 2013 Brian Thomas Matthews
 *
 * 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 com.btmatthews.junit.rules;

import org.junit.rules.TestRule;
import org.junit.runner.Description;
import org.junit.runners.model.Statement;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.text.MessageFormat;
import java.util.ResourceBundle;

/**
 * This JUnit rule generates log messages to delineate the start and finish of a JUnit test case and also to note any exceptions
 * that are thrown.
 *
 * @author Brian Matthews
 * @version 1.0.0
 */
public class LoggingRule implements TestRule {
    /**
     * The key for the message used to log the start of the test case.
     */
    private static final String START = "com.btmatthews.junit.rules.logging.START";
    /**
     * The key for the message used to log any exception thrown by the test case.
     */
    private static final String EXCEPTION = "com.btmatthews.junit.rules.logging.EXCEPTION";
    /**
     * The key for the message used to log the finish of the test case.
     */
    private static final String FINISH = "com.btmatthews.junit.rules.logging.FINISH";
    /**
     * The resource bundle from which the log messages are loaded.
     */
    private static final ResourceBundle messages = ResourceBundle.getBundle("com.btmatthews.junit.rules.messages");

    /**
     * Apply the test rule by building a wrapper {@link Statement} that logs a messages before and after evaluating
     * statement and if
     * @param statement The statement to be modified.
     * @param description A description of the test implemented in statement.
     * @return The modified statement.
     */
    public Statement apply(final Statement statement, final Description description) {
        return new Statement() {
            @Override
            public void evaluate() throws Throwable {
                final Logger logger = LoggerFactory.getLogger(description.getTestClass());
                logger.info(MessageFormat.format(messages.getString(START), description.getDisplayName()));
                try {
                    statement.evaluate();
                } catch (final Throwable e) {
                    logger.info(MessageFormat.format(messages.getString(EXCEPTION), description.getDisplayName()), e);
                    throw e;
                } finally {
                    logger.info(MessageFormat.format(messages.getString(FINISH), description.getDisplayName()));
                }
            }
        };
    }
}