org.conqat.lib.commons.string

Class LineOffsetConverter

java.lang.Object

org.conqat.lib.commons.collections.ManagedIntArray

org.conqat.lib.commons.string.LineOffsetConverter

All Implemented Interfaces:

java.io.Serializable

public class LineOffsetConverter
extends ManagedIntArray

A class that helps to convert between line numbers and character offsets. The character offset is zero based while the line number is one based.

This class works for strings with arbitrary line terminators.

The implementation works by storing all character offsets of the newline characters. For multi-character line endings (i.e. CR+LF on windows) the last offset is stored. For space/performance reasons, these offsets are stored in a bare array, which is managed by the base class.

Note: This class extends ManagedIntArray although delegation would be more elegant. The problem, however, is, that ManagedIntArray does not support delegation. The idea of this class was to provide protected access to its internals, which only works via inheritance. Actually, this is not interface inheritance (ManagedIntArray has no public method, btw.) but implementation inheritance.

See Also:

Serialized Form

Field Summary

Fields inherited from class org.conqat.lib.commons.collections.ManagedIntArray

array, size

Constructor Summary

Constructors

Constructor and Description
LineOffsetConverter(java.lang.String s) Constructor

Method Summary

Modifier and Type	Method and Description
int	getLine(int offset) Returns the (one based) line for the character at the given (zero based) offset.
int	getLineCount() Returns the number of lines of the input string.
int	getOffset(int line) Returns the (zero based) offset of the first character of the given line (starting at 1).
boolean	isValidLine(int line) Returns whether the given line is valid for the converter.

Methods inherited from class org.conqat.lib.commons.collections.ManagedIntArray

addArrayElement, addArrayElements

Methods inherited from class java.lang.Object

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

Constructor Detail

LineOffsetConverter

public LineOffsetConverter(java.lang.String s)

Constructor

Method Detail

getLineCount

public int getLineCount()

Returns the number of lines of the input string.

getOffset

public int getOffset(int line)

Returns the (zero based) offset of the first character of the given line (starting at 1).

Throws:

java.lang.AssertionError - if the line is not valid for the string.

isValidLine

public boolean isValidLine(int line)

Returns whether the given line is valid for the converter.

getLine

public int getLine(int offset)

Returns the (one based) line for the character at the given (zero based) offset. The newline at the end of a line is counted as a part of the line (i.e. for the very first newline, we would return 1). If the offset is larger than the length of the string, the index of the last line is returned.