org.crosswire.common.diff
Class Diff

java.lang.Object
  org.crosswire.common.diff.Diff

public class Diff
extends Object

Computes the difference between two texts to create a list of differences. Based on the LGPL Diff_Match_Patch v1.5 javascript of Neil Fraser, Copyright (C) 2006
http://neil.fraser.name/software/diff_match_patch/

Author:

DM Smith

See Also:

The GNU Lesser General Public License for details.

Field Summary

private boolean	checkLines Whether a slightly faster less optimal diff should be run.
private String	source The baseline text.
private String	target The changed text.

Constructor Summary

Diff(String source, String target)
Construct an object that can find the differences between two texts.

Diff(String source, String target, boolean checkLines)
Construct an object that can find the differences between two texts.

Method Summary

List<Difference>	compare() Find the differences between two texts.
private List<Difference>	compute() Find the differences between two texts.
String	prettyHtml(List<Difference> diffs) Convert a Difference list into a pretty HTML report.
int	xIndex(List<Difference> diffs, int loc) loc is a location in source, compute and return the equivalent location in target.

Methods inherited from class java.lang.Object

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

Field Detail

source

private String source

The baseline text.

target

private String target

The changed text.

checkLines

private boolean checkLines

Whether a slightly faster less optimal diff should be run.

Constructor Detail

Diff

public Diff(String source,
            String target)

Construct an object that can find the differences between two texts. Run a faster slightly less optimal diff. This constructor allows the 'checkLines' to be optional. Most of the time checkLines is wanted, so default to true.

Parameters:

source - Old string to be diffed

target - New string to be diffed

Diff

public Diff(String source,
            String target,
            boolean checkLines)

Construct an object that can find the differences between two texts.

Parameters:

source - Old string to be diffed

target - New string to be diffed

checkLines - Speedup flag. If false, then don't run a line-level diff first to identify the changed areas. If true, then run a faster slightly less optimal diff

Method Detail

compare

public List<Difference> compare()

Find the differences between two texts. Simplifies the problem by stripping any common prefix or suffix off the texts before diffing.

Returns:

List of Difference objects

compute

private List<Difference> compute()

Find the differences between two texts.

Returns:

List of Difference objects

xIndex

public int xIndex(List<Difference> diffs,
                  int loc)

loc is a location in source, compute and return the equivalent location in target. e.g. "The cat" vs "The big cat", 1->1, 5->8

Parameters:

diffs - List of Difference objects

loc - Location within source

Returns:

Location within target

prettyHtml

public String prettyHtml(List<Difference> diffs)

Convert a Difference list into a pretty HTML report.

Parameters:

diffs - List of Difference objects

Returns:

HTML representation