Splits the provided text into an array, separator specified, preserving all tokens, including empty tokens created by adjacent separators. : String split « Data Type « Java

1. Java
2. Data Type
3. String split

Splits the provided text into an array, separator specified, preserving all tokens, including empty tokens created by adjacent separators.

     
/*
 * 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.
 */
import java.util.ArrayList;
import java.util.List;

public class Main {

  /**
   * <p>Splits the provided text into an array, separator specified,
   * preserving all tokens, including empty tokens created by adjacent
   * separators. This is an alternative to using StringTokenizer.</p>
   *
   * <p>The separator is not included in the returned String array.
   * Adjacent separators are treated as separators for empty tokens.
   * For more control over the split use the StrTokenizer class.</p>
   *
   * <p>A <code>null</code> input String returns <code>null</code>.</p>
   *
   * <pre>
   * StringUtils.splitPreserveAllTokens(null, *)         = null
   * StringUtils.splitPreserveAllTokens("", *)           = []
   * StringUtils.splitPreserveAllTokens("a.b.c", '.')    = ["a", "b", "c"]
   * StringUtils.splitPreserveAllTokens("a..b.c", '.')   = ["a", "", "b", "c"]
   * StringUtils.splitPreserveAllTokens("a:b:c", '.')    = ["a:b:c"]
   * StringUtils.splitPreserveAllTokens("a\tb\nc", null) = ["a", "b", "c"]
   * StringUtils.splitPreserveAllTokens("a b c", ' ')    = ["a", "b", "c"]
   * StringUtils.splitPreserveAllTokens("a b c ", ' ')   = ["a", "b", "c", ""]
   * StringUtils.splitPreserveAllTokens("a b c  ", ' ')   = ["a", "b", "c", "", ""]
   * StringUtils.splitPreserveAllTokens(" a b c", ' ')   = ["", a", "b", "c"]
   * StringUtils.splitPreserveAllTokens("  a b c", ' ')  = ["", "", a", "b", "c"]
   * StringUtils.splitPreserveAllTokens(" a b c ", ' ')  = ["", a", "b", "c", ""]
   * </pre>
   *
   * @param str  the String to parse, may be <code>null</code>
   * @param separatorChar  the character used as the delimiter,
   *  <code>null</code> splits on whitespace
   * @return an array of parsed Strings, <code>null</code> if null String input
   * @since 2.1
   */
  public static String[] splitPreserveAllTokens(String str, char separatorChar) {
      return splitWorker(str, separatorChar, true);
  }

/**
 * Performs the logic for the <code>split</code> and 
 * <code>splitPreserveAllTokens</code> methods that do not return a
 * maximum array length.
 *
 * @param str  the String to parse, may be <code>null</code>
 * @param separatorChar the separate character
 * @param preserveAllTokens if <code>true</code>, adjacent separators are
 * treated as empty token separators; if <code>false</code>, adjacent
 * separators are treated as one separator.
 * @return an array of parsed Strings, <code>null</code> if null String input
 */
private static String[] splitWorker(String str, char separatorChar, boolean preserveAllTokens) {
    // Performance tuned for 2.0 (JDK1.4)

    if (str == null) {
        return null;
    }
    int len = str.length();
    if (len == 0) {
        return new String[0];
    }
    List list = new ArrayList();
    int i = 0, start = 0;
    boolean match = false;
    boolean lastMatch = false;
    while (i < len) {
        if (str.charAt(i) == separatorChar) {
            if (match || preserveAllTokens) {
                list.add(str.substring(start, i));
                match = false;
                lastMatch = true;
            }
            start = ++i;
            continue;
        }
        lastMatch = false;
        match = true;
        i++;
    }
    if (match || (preserveAllTokens && lastMatch)) {
        list.add(str.substring(start, i));
    }
    return (String[]) list.toArray(new String[list.size()]);
}

}

   
    
    
    
    
  

Related examples in the same category