content: /*
   * 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.cassandra.utils;
  
  import java.io.PrintStream;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  public interface OutputHandler
  {
      // called when an important info need to be displayed
      void output(String msg);
      default void output(String msg, Object ... args)
      {
          output(String.format(msg, args));
      }
  
      // called when a less important info need to be displayed
      void debug(String msg);
      default void debug(String msg, Object ... args)
      {
          debug(String.format(msg, args));
      }
  
      // called when the user needs to be warn
      void warn(String msg);
      void warn(Throwable th, String msg);
      default void warn(Throwable th)
      {
          warn(th, th.getMessage());
      }
      default void warn(Throwable th, String msg, Object... args)
      {
          warn(th, String.format(msg, args));
      }
      default void warn(String msg, Object ... args)
      {
          warn(String.format(msg, args));
      }
  
      class LogOutput implements OutputHandler
      {
          private static Logger logger = LoggerFactory.getLogger(LogOutput.class);
  
          public void output(String msg)
          {
              logger.info(msg);
          }
  
          public void debug(String msg)
          {
              logger.trace(msg);
          }
  
          public void warn(String msg)
          {
              logger.warn(msg);
          }
  
          public void warn(Throwable th, String msg)
          {
              logger.warn(msg, th);
          }
      }
  
      class SystemOutput implements OutputHandler
      {
          public final boolean debug;
          public final boolean printStack;
          public final PrintStream warnOut;
  
          public SystemOutput(boolean debug, boolean printStack)
          {
              this(debug, printStack, false);
          }
  
          public SystemOutput(boolean debug, boolean printStack, boolean logWarnToStdErr)
          {
              this.debug = debug;
              this.printStack = printStack;
              this.warnOut = logWarnToStdErr ? System.err : System.out;
          }
  
          public void output(String msg)
          {
              System.out.println(msg);
          }
  
          public void debug(String msg)
          {
              if (debug)
                  System.out.println(msg);
          }
  
          public void warn(String msg)
          {
              warn((Throwable) null, msg);
          }
  
          public void warn(Throwable th, String msg)
          {
              warnOut.println("WARNING: " + msg);
              if (printStack && th != null)
                  th.printStackTrace(warnOut);
          }
      }
  }