/**
* @param newVersion The String that is being compared to.
* @param oldVersion The String that is being compared against.
*/
private static List<WikiDiff> process(String newVersion, String oldVersion) {
logger.finer("Diffing: " + oldVersion + " against: " + newVersion);
if (newVersion.equals(oldVersion)) {
return new ArrayList<WikiDiff>();
}
String[] oldArray = DiffUtil.split(oldVersion);
String[] newArray = DiffUtil.split(newVersion);
Diff<String> diffObject = new Diff<String>(oldArray, newArray);
List<Difference> diffs = diffObject.diff();
return DiffUtil.generateWikiDiffs(diffs, oldArray, newArray);
}
/**
* Format the list of Difference objects into a list of WikiDiff objects, which will include
* information about what values are different and also include some unchanged values surrounded
* the changed values, thus giving some context.
*/
private static List<WikiDiff> generateWikiDiffs(
List<Difference> diffs, String[] oldArray, String[] newArray) {
List<WikiDiff> wikiDiffs = new ArrayList<WikiDiff>();
Difference previousDiff = null;
Difference nextDiff = null;
List<WikiDiff> changedLineWikiDiffs = null;
String[] oldLineArray = null;
String[] newLineArray = null;
List<Difference> changedLineDiffs = null;
List<WikiDiff> wikiSubDiffs = null;
Difference nextLineDiff = null;
int i = 0;
for (Difference currentDiff : diffs) {
i++;
wikiDiffs.addAll(
DiffUtil.preBufferDifference(
currentDiff, previousDiff, oldArray, newArray, DIFF_UNCHANGED_LINE_DISPLAY));
changedLineWikiDiffs = DiffUtil.processDifference(currentDiff, oldArray, newArray);
// loop through the difference and diff the individual lines so that it is possible to
// highlight the exact
// text that was changed
for (WikiDiff changedLineWikiDiff : changedLineWikiDiffs) {
oldLineArray = DiffUtil.stringToArray(changedLineWikiDiff.getOldText());
newLineArray = DiffUtil.stringToArray(changedLineWikiDiff.getNewText());
changedLineDiffs = new Diff<String>(oldLineArray, newLineArray).diff();
wikiSubDiffs = new ArrayList<WikiDiff>();
int j = 0;
for (Difference changedLineDiff : changedLineDiffs) {
// build sub-diff list, which is the difference for the individual
// line item
j++;
if (j == 1) {
// pre-buffering is only necessary for the first element as post-buffering
// will handle all further buffering when bufferAmount is -1.
wikiSubDiffs.addAll(
DiffUtil.preBufferDifference(
changedLineDiff, null, oldLineArray, newLineArray, -1));
}
wikiSubDiffs.addAll(
DiffUtil.processDifference(changedLineDiff, oldLineArray, newLineArray));
nextLineDiff = (j < changedLineDiffs.size()) ? changedLineDiffs.get(j) : null;
wikiSubDiffs.addAll(
DiffUtil.postBufferDifference(
changedLineDiff, nextLineDiff, oldLineArray, newLineArray, -1));
}
changedLineWikiDiff.setSubDiffs(wikiSubDiffs);
}
wikiDiffs.addAll(changedLineWikiDiffs);
nextDiff = (i < diffs.size()) ? diffs.get(i) : null;
wikiDiffs.addAll(
DiffUtil.postBufferDifference(
currentDiff, nextDiff, oldArray, newArray, DIFF_UNCHANGED_LINE_DISPLAY));
previousDiff = currentDiff;
}
return wikiDiffs;
}
private void loadDiff(
HttpServletRequest request,
ModelAndView next,
WikiPageInfo pageInfo,
String contents1,
String contents2)
throws Exception {
List<WikiDiff> diffs = DiffUtil.diff(contents1, contents2);
next.addObject("diffs", diffs);
}
/**
* Return a list of WikiDiff objects that can be used to create a display of the diff content.
*
* @param newVersion The String that is to be compared to, ie the later version of a topic.
* @param oldVersion The String that is to be considered as having changed, ie the earlier version
* of a topic.
* @return Returns a list of WikiDiff objects that correspond to the changed text.
*/
public static List<WikiDiff> diff(String newVersion, String oldVersion)
throws DataAccessException {
List<WikiDiff> result = DiffUtil.retrieveFromCache(newVersion, oldVersion);
if (result != null) {
return result;
}
String version1 = newVersion;
String version2 = oldVersion;
if (version2 == null) {
version2 = "";
}
if (version1 == null) {
version1 = "";
}
// remove line-feeds to avoid unnecessary noise in the diff due to
// cut & paste or other issues
version2 = StringUtils.remove(version2, '\r');
version1 = StringUtils.remove(version1, '\r');
result = DiffUtil.process(version1, version2);
DiffUtil.addToCache(newVersion, oldVersion, result);
return result;
}
private void resolve(HttpServletRequest request, ModelAndView next, WikiPageInfo pageInfo)
throws Exception {
String topicName = JAMWikiServlet.getTopicFromRequest(request);
String virtualWiki = JAMWikiServlet.getVirtualWikiFromURI(request);
TopicVersion version = WikiBase.getHandler().lookupLastTopicVersion(virtualWiki, topicName);
String contents1 = version.getVersionContent();
String contents2 = request.getParameter("contents");
next.addObject("lastTopicVersionId", new Integer(version.getTopicVersionId()));
next.addObject("contents", contents1);
next.addObject("contentsResolve", contents2);
Vector diffs = DiffUtil.diff(contents1, contents2);
next.addObject("diffs", diffs);
loadEdit(request, next, pageInfo, virtualWiki, topicName, false);
pageInfo.setAction(WikiPageInfo.ACTION_EDIT_RESOLVE);
}
