ExceptionLogHandler.java

/**
 * Copyright 2010 Google Inc.
 *
 * 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.waveprotocol.box.server.util.testing;

import java.util.logging.Handler;
import java.util.logging.Level;
import java.util.logging.LogRecord;

/**
 * A log handler which throws a runtime exception at and above a set log level.
 * Useful for catching erroneous conditions during testing, which are only
 * reported to the logs.
 *
 * @author mk.mateng@gmail.com (Michael Kuntzman)
 */
public class ExceptionLogHandler extends Handler {
  /** The integer value of the minimum fatal log level. */
  private final int fatalLevel;

  /**
   * Constructs an ExceptionLogHandler that throws a runtime exception at and above the specified
   * log level.
   *
   * @param fatalLevel the minimum log level for which to throw an exception.
   */
  public ExceptionLogHandler(Level fatalLevel) {
    this.fatalLevel = fatalLevel.intValue();
  }

  /**
   * @throws RuntimeException if the log record is at or above the fatal log level.
   */
  @Override
  public void publish(LogRecord record) {
    if (record.getLevel().intValue() >= fatalLevel) {
      throw new RuntimeException(record.getLevel() + ": " + record.getMessage(),
          record.getThrown());
    }
  }

  @Override
  public void flush() {
  }

  @Override
  public void close() {
  }
}