org.apache.catalina.util
Class StringParser

java.lang.Object
  org.apache.catalina.util.StringParser

public final class StringParser
extends Object

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.

Version:

$Id: StringParser.java 939305 2010-04-29 13:43:39Z kkolinko $

Author:

Craig R. McClanahan

Constructor Summary

StringParser()
Construct a string parser with no preset string to be parsed.

StringParser(String string)
Construct a string parser that is initialized to parse the specified string.

Method Summary

void	advance() Advance the current parsing position by one, if we are not already past the end of the string.
String	extract(int start) Extract and return a substring that starts at the specified position, and extends to the end of the string being parsed.
String	extract(int start, int end) Extract and return a substring that starts at the specified position, and ends at the character before the specified position.
int	findChar(char ch) 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.
int	findText() 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.
int	findWhite() 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.
int	getIndex() Return the zero-relative index of our current parsing position within the string being parsed.
int	getLength() Return the length of the string we are parsing.
String	getString() Return the String we are currently parsing.
protected boolean	isWhite(char ch) Is the specified character considered to be whitespace?
void	reset() Reset the current state of the parser to the beginning of the current string being parsed.
void	setString(String string) Set the String we are currently parsing.
int	skipChar(char ch) Advance the current parsing position while it is pointing at the specified character, or until it moves past the end of the string.
int	skipText() Advance the current parsing position while it is pointing at a non-whitespace character, or until it moves past the end of the string.
int	skipWhite() Advance the current parsing position while it is pointing at a whitespace character, or until it moves past the end of the string.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

StringParser

public StringParser()

Construct a string parser with no preset string to be parsed.

StringParser

public StringParser(String string)

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

Parameters:

string - The string to be parsed

Method Detail

getIndex

public int getIndex()

Return the zero-relative index of our current parsing position within the string being parsed.

getLength

public int getLength()

Return the length of the string we are parsing.

getString

public String getString()

Return the String we are currently parsing.

setString

public void setString(String string)

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.

advance

public void advance()

Advance the current parsing position by one, if we are not already past the end of the string.

extract

public String extract(int start)

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

extract

public String extract(int start,
                      int end)

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

findChar

public int findChar(char ch)

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

findText

public int findText()

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.

findWhite

public int findWhite()

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.

reset

public void reset()

Reset the current state of the parser to the beginning of the current string being parsed.

skipChar

public int skipChar(char ch)

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

skipText

public int skipText()

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.

skipWhite

public int skipWhite()

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.

isWhite

protected boolean isWhite(char ch)

Is the specified character considered to be whitespace?

Parameters:

ch - Character to be checked