/* * 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.log4j.helpers;import org.apache.log4j.spi.LoggingEvent;/**   <p>PatternConverter is an abtract class that provides the   formatting functionality that derived classes need.   <p>Conversion specifiers in a conversion patterns are parsed to   individual PatternConverters. Each of which is responsible for   converting a logging event in a converter specific manner.   @author <a href="mailto:cakalijp@Maritz.com">James P. Cakalic</a>   @author Ceki G&uuml;lc&uuml;   @since 0.8.2 */public abstract class PatternConverter {  public PatternConverter next;  int min = -1;  int max = 0x7FFFFFFF;  boolean leftAlign = false;  protected  PatternConverter() {  }    protected  PatternConverter(FormattingInfo fi) {    min = fi.min;    max = fi.max;    leftAlign = fi.leftAlign;  }  /**     Derived pattern converters must override this method in order to     convert conversion specifiers in the correct way.  */  abstract  protected  String convert(LoggingEvent event);  /**     A template method for formatting in a converter specific way.   */  public  void format(StringBuffer sbuf, LoggingEvent e) {    String s = convert(e);    if(s == null) {      if(0 < min)	spacePad(sbuf, min);      return;    }    int len = s.length();    if(len > max)      sbuf.append(s.substring(len-max));    else if(len < min) {      if(leftAlign) {		sbuf.append(s);	spacePad(sbuf, min-len);      }      else {	spacePad(sbuf, min-len);	sbuf.append(s);      }    }    else      sbuf.append(s);  }	  static String[] SPACES = {" ", "  ", "    ", "        ", //1,2,4,8 spaces			    "                ", // 16 spaces			    "                                " }; // 32 spaces  /**     Fast space padding method.  */  public  void spacePad(StringBuffer sbuf, int length) {    while(length >= 32) {      sbuf.append(SPACES[5]);      length -= 32;    }        for(int i = 4; i >= 0; i--) {	      if((length & (1<<i)) != 0) {	sbuf.append(SPACES[i]);      }    }  }}