Truncate text on a whitespace boundary (near a specified length) : String Strip « Data Type « Java






  1. Java
  2. Data Type
  3. String Strip

Truncate text on a whitespace boundary (near a specified length)

    
/**********************************************************************************
 *
 * Copyright (c) 2003, 2004 The Regents of the University of Michigan, Trustees of Indiana University,
 *                  Board of Trustees of the Leland Stanford, Jr., University, and The MIT Corporation
 *
 * Licensed under the Educational Community License Version 1.0 (the "License");
 * By obtaining, using and/or copying this Original Work, you agree that you have read,
 * understand, and will comply with the terms and conditions of the Educational Community License.
 * You may obtain a copy of the License at:
 *
 *      http://cvs.sakaiproject.org/licenses/license_1_0.html
 *
 * 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.
 *
 **********************************************************************************/

public class Utils {
  private static final int MINIMUM_SUPPORTED_LENGTH = 4;
  
  /**
   * Truncate text on a whitespace boundary (near a specified length). The
   * length of the resultant string will be in the range:<br>
   * <code>   (requested-length * .25) ~ (requested-length * 1.5) </code>
   * 
   * @param text
   *          Text to truncate
   * @param length
   *          Target length
   * @return Truncated text
   */
  public static String truncateAtWhitespace(String text, int length) {
    int desired, lowerBound, upperBound;
    /*
     * Make sure we have a reasonable length to work with
     */
    if (length < MINIMUM_SUPPORTED_LENGTH) {
      throw new IllegalArgumentException("Requested length too short (must be "
          + MINIMUM_SUPPORTED_LENGTH + " or greated)");
    }
    /*
     * No need to truncate - the original string "fits"
     */
    if (text.length() <= length) {
      return text;
    }
    /*
     * Try to find whitespace befor the requested maximum
     */
    lowerBound = length / 4;
    upperBound = length + (length / 2);

    for (int i = length - 1; i > lowerBound; i--) {
      if (Character.isWhitespace(text.charAt(i))) {
        return text.substring(0, i);
      }
    }
    /*
     * No whitespace - look beyond the desired maximum
     */
    for (int i = (length); i < upperBound; i++) {
      if (Character.isWhitespace(text.charAt(i))) {
        return text.substring(0, i);
      }
    }
    /*
     * No whitespace, just truncate the text at the requested length
     */
    return text.substring(0, length);
  }
}








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