org.crosswire.common.diff
Class DifferenceEngine

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

public class DifferenceEngine
extends Object

Builds a map of a baseline/source text and a changed/target text, navigating it to determine 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 String	source Made final because we now rely on caching the string lengths (they could be cached at method level if require non-final in future) The baseline text.
private int	sourceLength
private String	target The changed text.
private int	targetLength
private static float	timeout
private static float	TIMEOUT Number of seconds to map a diff before giving up.

Constructor Summary

DifferenceEngine()
Empty Difference Engine, which won't find anything.

DifferenceEngine(String source, String target)
Find the differences between two texts.

Method Summary

List<Difference>	generate() Explore the intersection points between the two texts.
protected List<Difference>	path1(List<Set<String>> vMap, String newSource, String newTarget) Work from the middle back to the start to determine the path.
protected List<Difference>	path2(List<Set<String>> vMap, String newSource, String newTarget) Work from the middle back to the end to determine the path.
static void	setTimeout(float newTimeout) Set the timeout for the diff operation.

Methods inherited from class java.lang.Object

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

Field Detail

TIMEOUT

private static final float TIMEOUT

Number of seconds to map a diff before giving up. Use 0 for infinity.

See Also:

Constant Field Values

timeout

private static float timeout

source

private final String source

Made final because we now rely on caching the string lengths (they could be cached at method level if require non-final in future) The baseline text.

target

private final String target

The changed text.

targetLength

private final int targetLength

sourceLength

private final int sourceLength

Constructor Detail

DifferenceEngine

public DifferenceEngine()

Empty Difference Engine, which won't find anything.

DifferenceEngine

public DifferenceEngine(String source,
                        String target)

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

Parameters:

source - Old string to be diffed

target - New string to be diffed

Method Detail

generate

public List<Difference> generate()

Explore the intersection points between the two texts.

Returns:

List of Difference objects or null if no diff available

path1

protected List<Difference> path1(List<Set<String>> vMap,
                                 String newSource,
                                 String newTarget)

Work from the middle back to the start to determine the path.

Parameters:

vMap - List of path sets.

newSource - Old string fragment to be diffed

newTarget - New string fragment to be diffed

Returns:

List of Difference objects

path2

protected List<Difference> path2(List<Set<String>> vMap,
                                 String newSource,
                                 String newTarget)

Work from the middle back to the end to determine the path.

Parameters:

vMap - List of path sets.

newSource - Old string fragment to be diffed

newTarget - New string fragment to be diffed

Returns:

List of Difference objects

setTimeout

public static void setTimeout(float newTimeout)

Set the timeout for the diff operation. The default is 1 second. Use 0 for infinity.

Parameters:

newTimeout - the new timeout