/apache-log4j-1.2.17/src/main/java/org/apache/log4j/pattern/FormattingInfo.java

  1/*
  2 * Licensed to the Apache Software Foundation (ASF) under one or more
  3 * contributor license agreements.  See the NOTICE file distributed with
  4 * this work for additional information regarding copyright ownership.
  5 * The ASF licenses this file to You under the Apache License, Version 2.0
  6 * (the "License"); you may not use this file except in compliance with
  7 * the License.  You may obtain a copy of the License at
  8 *
  9 *      http://www.apache.org/licenses/LICENSE-2.0
 10 *
 11 * Unless required by applicable law or agreed to in writing, software
 12 * distributed under the License is distributed on an "AS IS" BASIS,
 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 14 * See the License for the specific language governing permissions and
 15 * limitations under the License.
 16 */
 17
 18package org.apache.log4j.pattern;
 19
 20
 21/**
 22 * Modifies the output of a pattern converter for a specified minimum
 23 * and maximum width and alignment.
 24 *
 25 *
 26 *  @author <a href=mailto:jim_cakalic@na.biomerieux.com>Jim Cakalic</a>
 27 *  @author Ceki G&uuml;lc&uuml;
 28 *  @author Curt Arnold
 29 *
 30 */
 31public final class FormattingInfo {
 32  /**
 33   *  Array of spaces.
 34   */
 35  private static final char[] SPACES =
 36    new char[] { ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ' };
 37
 38  /**
 39   * Default instance.
 40   */
 41  private static final FormattingInfo DEFAULT =
 42    new FormattingInfo(false, 0, Integer.MAX_VALUE);
 43
 44  /**
 45   * Minimum length.
 46   */
 47  private final int minLength;
 48
 49  /**
 50   * Maximum length.
 51   */
 52  private final int maxLength;
 53
 54  /**
 55   * Alignment.
 56   */
 57  private final boolean leftAlign;
 58
 59  /**
 60   * Creates new instance.
 61   * @param leftAlign left align if true.
 62   * @param minLength minimum length.
 63   * @param maxLength maximum length.
 64   */
 65  public FormattingInfo(
 66    final boolean leftAlign, final int minLength, final int maxLength) {
 67    this.leftAlign = leftAlign;
 68    this.minLength = minLength;
 69    this.maxLength = maxLength;
 70  }
 71
 72  /**
 73   * Gets default instance.
 74   * @return default instance.
 75   */
 76  public static FormattingInfo getDefault() {
 77    return DEFAULT;
 78  }
 79
 80  /**
 81   * Determine if left aligned.
 82   * @return true if left aligned.
 83   */
 84  public boolean isLeftAligned() {
 85    return leftAlign;
 86  }
 87
 88  /**
 89   * Get minimum length.
 90   * @return minimum length.
 91   */
 92  public int getMinLength() {
 93    return minLength;
 94  }
 95
 96  /**
 97   * Get maximum length.
 98   * @return maximum length.
 99   */
100  public int getMaxLength() {
101    return maxLength;
102  }
103
104  /**
105   * Adjust the content of the buffer based on the specified lengths and alignment.
106   *
107   * @param fieldStart start of field in buffer.
108   * @param buffer buffer to be modified.
109   */
110  public void format(final int fieldStart, final StringBuffer buffer) {
111    final int rawLength = buffer.length() - fieldStart;
112
113    if (rawLength > maxLength) {
114      buffer.delete(fieldStart, buffer.length() - maxLength);
115    } else if (rawLength < minLength) {
116      if (leftAlign) {
117        final int fieldEnd = buffer.length();
118        buffer.setLength(fieldStart + minLength);
119
120        for (int i = fieldEnd; i < buffer.length(); i++) {
121          buffer.setCharAt(i, ' ');
122        }
123      } else {
124        int padLength = minLength - rawLength;
125
126        for (; padLength > 8; padLength -= 8) {
127          buffer.insert(fieldStart, SPACES);
128        }
129
130        buffer.insert(fieldStart, SPACES, 0, padLength);
131      }
132    }
133  }
134}