Start line:  
End line:  

Snippet Preview

Snippet HTML Code

Stack Overflow Questions
  /*
   * 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.catalina.util;


Utility class for string parsing that is higher performance than StringParser for simple delimited text cases. Parsing is performed by setting the string, and then using the findXxxx() and skipXxxx() families of methods to remember significant offsets. To retrieve the parsed substrings, call the extract() method with the appropriate saved offset values.

Author(s):
Craig R. McClanahan
Version:
$Revision: 515 $ $Date: 2008-03-17 22:02:23 +0100 (Mon, 17 Mar 2008) $
 
 
 public final class StringParser {
 
 
     // ----------------------------------------------------------- Constructors
 

    
Construct a string parser with no preset string to be parsed.
 
     public StringParser() {
 
         this(null);
 
     }


    
Construct a string parser that is initialized to parse the specified string.

Parameters:
string The string to be parsed
 
     public StringParser(String string) {
 
         super();
         setString(string);
 
     }
 
 
     // ----------------------------------------------------- Instance Variables
 

    
The characters of the current string, as a character array. Stored when the string is first specified to speed up access to characters being compared during parsing.
 
     private char chars[] = null;


    
The zero-relative index of the current point at which we are positioned within the string being parsed. NOTE: the value of this index can be one larger than the index of the last character of the string (i.e. equal to the string length) if you parse off the end of the string. This value is useful for extracting substrings that include the end of the string.
 
     private int index = 0;


    
The length of the String we are currently parsing. Stored when the string is first specified to avoid repeated recalculations.
 
     private int length = 0;


    
The String we are currently parsing.
 
     private String string = null;
 
 
     // ------------------------------------------------------------- Properties


    
Return the zero-relative index of our current parsing position within the string being parsed.
    public int getIndex() {
        return (this.);
    }


    
Return the length of the string we are parsing.
    public int getLength() {
        return (this.);
    }


    
Return the String we are currently parsing.
    public String getString() {
        return (this.);
    }


    
Set the String we are currently parsing. The parser state is also reset to begin at the start of this string.

Parameters:
string The string to be parsed.
    public void setString(String string) {
        this. = string;
        if (string != null) {
            this. = string.length();
             = this..toCharArray();
        } else {
            this. = 0;
             = new char[0];
        }
        reset();
    }
    // --------------------------------------------------------- Public Methods


    
Advance the current parsing position by one, if we are not already past the end of the string.
    public void advance() {
        if ( < )
            ++;
    }


    
Extract and return a substring that starts at the specified position, and extends to the end of the string being parsed. If this is not possible, a zero-length string is returned.

Parameters:
start Starting index, zero relative, inclusive
    public String extract(int start) {
        if ((start < 0) || (start >= ))
            return ("");
        else
            return (.substring(start));
    }


    
Extract and return a substring that starts at the specified position, and ends at the character before the specified position. If this is not possible, a zero-length string is returned.

Parameters:
start Starting index, zero relative, inclusive
end Ending index, zero relative, exclusive
    public String extract(int startint end) {
        if ((start < 0) || (start >= end) || (end > ))
            return ("");
        else
            return (.substring(startend));
    }


    
Return the index of the next occurrence of the specified character, or the index of the character after the last position of the string if no more occurrences of this character are found. The current parsing position is updated to the returned value.

Parameters:
ch Character to be found
    public int findChar(char ch) {
        while (( < ) && (ch != []))
            ++;
        return ();
    }


    
Return the index of the next occurrence of a non-whitespace character, or the index of the character after the last position of the string if no more non-whitespace characters are found. The current parsing position is updated to the returned value.
    public int findText() {
        while (( < ) && isWhite([]))
            ++;
        return ();
    }


    
Return the index of the next occurrence of a whitespace character, or the index of the character after the last position of the string if no more whitespace characters are found. The current parsing position is updated to the returned value.
    public int findWhite() {
        while (( < ) && !isWhite([]))
            ++;
        return ();
    }


    
Reset the current state of the parser to the beginning of the current string being parsed.
    public void reset() {
         = 0;
    }


    
Advance the current parsing position while it is pointing at the specified character, or until it moves past the end of the string. Return the final value.

Parameters:
ch Character to be skipped
    public int skipChar(char ch) {
        while (( < ) && (ch == []))
            ++;
        return ();
    }


    
Advance the current parsing position while it is pointing at a non-whitespace character, or until it moves past the end of the string. Return the final value.
    public int skipText() {
        while (( < ) && !isWhite([]))
            ++;
        return ();
    }


    
Advance the current parsing position while it is pointing at a whitespace character, or until it moves past the end of the string. Return the final value.
    public int skipWhite() {
        while (( < ) && isWhite([]))
            ++;
        return ();
    }
    // ------------------------------------------------------ Protected Methods


    
Is the specified character considered to be whitespace?

Parameters:
ch Character to be checked
    protected boolean isWhite(char ch) {
        if ((ch == ' ') || (ch == '\t') || (ch == '\r') || (ch == '\n'))
            return (true);
        else
            return (false);
    }
New to GrepCode? Check out our FAQ X