package org.apache.log4j;
 
import java.io.File;
import java.io.Writer;
import java.io.FileWriter;
import java.io.BufferedWriter;
import org.apache.log4j.spi.LoggingEvent;
import org.apache.log4j.helpers.OptionConverter;
import org.apache.log4j.spi.ErrorHandler;

/**
   TempFileAppender creates new unique file for each logging statement.
 
   @author Leos Literak
   @author Ceki Gülcü
 
*/
public class TempFileAppender extends AppenderSkeleton {
 
  /**
     A string constant used in naming the option for setting the
     directory where the log files will be created. Current value 
     of this string constant is Path. java.io.tmpdir directory
     will be used, if ommited.
   */
  static final public String PATH_OPTION = "Path";
  
  /**
     The default path is actual directory.
  */
  protected String path = null;
 
  /**
     A string constant used in naming the option for setting the
     prefix of the log files. It has to have at least 3 characters!
     Current value of this string constant is Prefix.
   */
  static final public String PREFIX_OPTION = "Prefix";
  
  /**
     The default path is actual directory.
  */
  protected String prefix = "l4j_";
 
  /**
     A string constant used in naming the option for setting the
     suffix of the log files. Current value of this string constant 
     is Suffix.
   */
  static final public String SUFFIX_OPTION = "Suffix";
  
  /**
     The default path is actual directory.
  */
  protected String suffix = ".tmp";
  
  /**
     Default dir
  */
  
  protected File dir = null;




  /**
     The default constructor simply calls its parent's constructor. 
  */
  public TempFileAppender() {
      super();
  }
 
  /**
     Retuns the option names for this component
  */
  public String[] getOptionStrings() {
      return OptionConverter.concatanateArrays(super.getOptionStrings(),
                 new String[] {PATH_OPTION,PREFIX_OPTION,SUFFIX_OPTION});
  }  

  /**
     Set TempFileAppender specific options.
 
     The recognized options are Path, Prefix and Suffix,
     i.e. the values of the string constants {@link #PATH_OPTION}, 
     {@link #PREFIX_OPTION} and respectively {@link #SUFFIX_OPTION}. 
     The options of the super class {@link AppenderSkeleton} are also 
     recognized.
  */
  
  public void setOption(String key, String value) {
      super.setOption(key, value);
      if(key.equalsIgnoreCase(PATH_OPTION)) {
	  path = value;
	  if(path==null) {
              errorHandler.error("Path cannot be empty!",null,0);
	  }

	  dir = new File(path);
	  if(!(dir.exists() && dir.isDirectory() && dir.canWrite())) {
              errorHandler.error("Cannot write to directory " + path + "!",null,0);
	  }
      }
      else if(key.equalsIgnoreCase(PREFIX_OPTION)) {
          if(value!=null && value.length()>=3) {
	      prefix = value;
	  } else {
              errorHandler.error("Prefix cannot be shorter than 3 characters!",
	                         null,0);
	  }
      }
      else if(key.equalsIgnoreCase(SUFFIX_OPTION)) {
          if(value!=null && value.length()>=1) {
	      suffix = value;
	  } else {
              errorHandler.error("Suffix cannot be empty!",null,0);
	  }
      }
  }

  /**
     This method is called by {@link AppenderSkeleton#doAppend}
     method.
 
     
Whenever this method is called, new unique file is created
     with specified prefix and suffix. The file is closed afterwards.
 
     
The format of the output will depend on this appender's
     layout.
 
  */ 
  public void append(LoggingEvent event) { 
      if(!checkEntryConditions()) {
          return;
      }
      subAppend(event);
  }
 
  /**
     This method determines if there is a sense in attempting to append.
  */
  protected boolean checkEntryConditions() {
      return true;
  }   

  /**
     This method does actual writing
  */
  protected void subAppend(LoggingEvent event) {
      try {
          File tmp = File.createTempFile(prefix,suffix,dir);
	  Writer out = new BufferedWriter(new FileWriter(tmp));
	  out.write(event.message);
	  out.close();
 /* this Appender is not supposed to be used for logging of Exceptions */
      } catch (Exception e) {
          errorHandler.error("Error during creation of temporary File!",e,1);
      }
  }
  
  public boolean requiresLayout() {
      return false;
  }
  
  public void close() {
  /* nothing to do */
  }
} 
/*
 * @author $Author: ceki $
 * @version $Revision: 1.1 $
 * @since $Date: 2001/04/20 17:38:31 $
 *
 * $Log: TempFileAppender.java,v $
 * Revision 1.1  2001/04/20 17:38:31  ceki
 *
 * Added LeosLiterak's TempFileAppender.java
 *
*/