FileLoggerModule.java

/**
 * The MIT License Copyright (c) 2014 Ilkka Seppälä
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
 * associated documentation files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge, publish, distribute,
 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or
 * substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
 * NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
package com.iluwatar.module;

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintStream;

import org.apache.log4j.Logger;

/**
 * The FileLoggerModule is responsible for showing logs on File System
 * <p>
 * The below example demonstrates a File logger module, which can print simple and error messages in
 * two designated files
 */
public final class FileLoggerModule {

  private static final Logger LOGGER = Logger.getLogger(FileLoggerModule.class);

  private static FileLoggerModule singleton = null;

  private static final String OUTPUT_FILE = "output.txt";
  private static final String ERROR_FILE = "error.txt";

  public PrintStream output = null;
  public PrintStream error = null;

  private FileLoggerModule() {}

  /**
   * Static method to get single instance of class
   * 
   * @return singleton instance of FileLoggerModule
   */
  public static FileLoggerModule getSingleton() {

    if (FileLoggerModule.singleton == null) {
      FileLoggerModule.singleton = new FileLoggerModule();
    }

    return FileLoggerModule.singleton;
  }

  /**
   * Following method performs the initialization
   * 
   * @throws FileNotFoundException if program is not able to find log files (output.txt and
   *         error.txt)
   */
  public FileLoggerModule prepare() throws FileNotFoundException {

    LOGGER.debug("FileLoggerModule::prepare();");

    this.output = new PrintStream(new FileOutputStream(OUTPUT_FILE));
    this.error = new PrintStream(new FileOutputStream(ERROR_FILE));

    return this;
  }

  /**
   * Following method performs the finalization
   */
  public void unprepare() {

    if (this.output != null) {

      this.output.flush();
      this.output.close();
    }

    if (this.error != null) {

      this.error.flush();
      this.error.close();
    }

    LOGGER.debug("FileLoggerModule::unprepare();");
  }

  /**
   * Used to print a message
   * 
   * @param value will be printed in file
   */
  public void printString(final String value) {
    this.output.println(value);
  }

  /**
   * Used to print a error message
   * 
   * @param value will be printed on error file
   */
  public void printErrorString(final String value) {
    this.error.println(value);
  }
}