/* (non-Javadoc)
* @see Lucene.Net.Highlight.FragmentScorer#startFragment(Lucene.Net.Highlight.TextFragment)
*/
public virtual void StartFragment(TextFragment newFragment)
{
uniqueTermsInFragment = new System.Collections.Hashtable();
currentTextFragment = newFragment;
totalScore = 0;
}
/// <param name="frag2">Fragment to be merged into this one
/// </param>
public virtual void Merge(TextFragment frag2)
{
textEndPos = frag2.textEndPos;
score = System.Math.Max(score, frag2.score);
}
/// <param name="fragment">
/// </param>
/// <returns> true if this fragment follows the one passed
/// </returns>
public virtual bool Follows(TextFragment fragment)
{
return textStartPos == fragment.textEndPos;
}
/// <summary> Low level api to get the most relevant (formatted) sections of the document.
/// This method has been made public to allow visibility of score information held in TextFragment objects.
/// Thanks to Jason Calabrese for help in redefining the interface.
/// </summary>
/// <param name="">tokenStream
/// </param>
/// <param name="">text
/// </param>
/// <param name="">maxNumFragments
/// </param>
/// <param name="">mergeContiguousFragments
/// </param>
/// <throws> IOException </throws>
public TextFragment[] GetBestTextFragments(TokenStream tokenStream, System.String text, bool mergeContiguousFragments, int maxNumFragments)
{
System.Collections.ArrayList docFrags = new System.Collections.ArrayList();
System.Text.StringBuilder newText = new System.Text.StringBuilder();
TextFragment currentFrag = new TextFragment(newText, newText.Length, docFrags.Count);
fragmentScorer.StartFragment(currentFrag);
docFrags.Add(currentFrag);
FragmentQueue fragQueue = new FragmentQueue(maxNumFragments);
try
{
Lucene.Net.Analysis.Token token;
System.String tokenText;
int startOffset;
int endOffset;
int lastEndOffset = 0;
textFragmenter.Start(text);
TokenGroup tokenGroup = new TokenGroup();
token = tokenStream.Next();
while ((token != null) && (token.StartOffset() < maxDocBytesToAnalyze))
{
if ((tokenGroup.numTokens > 0) && (tokenGroup.IsDistinct(token)))
{
//the current token is distinct from previous tokens -
// markup the cached token group info
startOffset = tokenGroup.matchStartOffset;
endOffset = tokenGroup.matchEndOffset;
tokenText = text.Substring(startOffset, (endOffset) - (startOffset));
System.String markedUpText = formatter.HighlightTerm(encoder.EncodeText(tokenText), tokenGroup);
//store any whitespace etc from between this and last group
if (startOffset > lastEndOffset)
newText.Append(encoder.EncodeText(text.Substring(lastEndOffset, (startOffset) - (lastEndOffset))));
newText.Append(markedUpText);
lastEndOffset = System.Math.Max(endOffset, lastEndOffset);
tokenGroup.Clear();
//check if current token marks the start of a new fragment
if (textFragmenter.IsNewFragment(token))
{
currentFrag.SetScore(fragmentScorer.GetFragmentScore());
//record stats for a new fragment
currentFrag.textEndPos = newText.Length;
currentFrag = new TextFragment(newText, newText.Length, docFrags.Count);
fragmentScorer.StartFragment(currentFrag);
docFrags.Add(currentFrag);
}
}
tokenGroup.AddToken(token, fragmentScorer.GetTokenScore(token));
// if(lastEndOffset>maxDocBytesToAnalyze)
// {
// break;
// }
token = tokenStream.Next();
}
currentFrag.SetScore(fragmentScorer.GetFragmentScore());
if (tokenGroup.numTokens > 0)
{
//flush the accumulated text (same code as in above loop)
startOffset = tokenGroup.matchStartOffset;
endOffset = tokenGroup.matchEndOffset;
tokenText = text.Substring(startOffset, (endOffset) - (startOffset));
System.String markedUpText = formatter.HighlightTerm(encoder.EncodeText(tokenText), tokenGroup);
//store any whitespace etc from between this and last group
if (startOffset > lastEndOffset)
newText.Append(encoder.EncodeText(text.Substring(lastEndOffset, (startOffset) - (lastEndOffset))));
newText.Append(markedUpText);
lastEndOffset = System.Math.Max(lastEndOffset, endOffset);
}
//Test what remains of the original text beyond the point where we stopped analyzing
if ((lastEndOffset < text.Length) && (text.Length < maxDocBytesToAnalyze))
{
//append it to the last fragment
newText.Append(encoder.EncodeText(text.Substring(lastEndOffset)));
}
currentFrag.textEndPos = newText.Length;
//sort the most relevant sections of the text
for (System.Collections.IEnumerator i = docFrags.GetEnumerator(); i.MoveNext(); )
{
currentFrag = (TextFragment) i.Current;
//If you are running with a version of Lucene before 11th Sept 03
// you do not have PriorityQueue.insert() - so uncomment the code below
/*
if (currentFrag.getScore() >= minScore)
{
fragQueue.put(currentFrag);
if (fragQueue.size() > maxNumFragments)
{ // if hit queue overfull
fragQueue.pop(); // remove lowest in hit queue
minScore = ((TextFragment) fragQueue.top()).getScore(); // reset minScore
}
}
*/
//The above code caused a problem as a result of Christoph Goller's 11th Sept 03
//fix to PriorityQueue. The correct method to use here is the new "insert" method
// USE ABOVE CODE IF THIS DOES NOT COMPILE!
fragQueue.Insert(currentFrag);
}
//return the most relevant fragments
TextFragment[] frag = new TextFragment[fragQueue.Size()];
for (int i = frag.Length - 1; i >= 0; i--)
{
frag[i] = (TextFragment) fragQueue.Pop();
}
//merge any contiguous fragments to improve readability
if (mergeContiguousFragments)
{
MergeContiguousFragments(frag);
System.Collections.ArrayList fragTexts = new System.Collections.ArrayList();
for (int i = 0; i < frag.Length; i++)
{
if ((frag[i] != null) && (frag[i].GetScore() > 0))
{
fragTexts.Add(frag[i]);
}
}
frag = (TextFragment[]) fragTexts.ToArray(typeof(TextFragment));
}
return frag;
}
finally
{
if (tokenStream != null)
{
try
{
tokenStream.Close();
}
catch (System.Exception e)
{
}
}
}
}
/// <summary>Improves readability of a score-sorted list of TextFragments by merging any fragments
/// that were contiguous in the original text into one larger fragment with the correct order.
/// This will leave a "null" in the array entry for the lesser scored fragment.
///
/// </summary>
/// <param name="frag">An array of document fragments in descending score
/// </param>
private void MergeContiguousFragments(TextFragment[] frag)
{
bool mergingStillBeingDone;
if (frag.Length > 1)
do
{
mergingStillBeingDone = false; //initialise loop control flag
//for each fragment, scan other frags looking for contiguous blocks
for (int i = 0; i < frag.Length; i++)
{
if (frag[i] == null)
{
continue;
}
//merge any contiguous blocks
for (int x = 0; x < frag.Length; x++)
{
if (frag[x] == null)
{
continue;
}
if (frag[i] == null)
{
break;
}
TextFragment frag1 = null;
TextFragment frag2 = null;
int frag1Num = 0;
int frag2Num = 0;
int bestScoringFragNum;
int worstScoringFragNum;
//if blocks are contiguous....
if (frag[i].Follows(frag[x]))
{
frag1 = frag[x];
frag1Num = x;
frag2 = frag[i];
frag2Num = i;
}
else if (frag[x].Follows(frag[i]))
{
frag1 = frag[i];
frag1Num = i;
frag2 = frag[x];
frag2Num = x;
}
//merging required..
if (frag1 != null)
{
if (frag1.GetScore() > frag2.GetScore())
{
bestScoringFragNum = frag1Num;
worstScoringFragNum = frag2Num;
}
else
{
bestScoringFragNum = frag2Num;
worstScoringFragNum = frag1Num;
}
frag1.Merge(frag2);
frag[worstScoringFragNum] = null;
mergingStillBeingDone = true;
frag[bestScoringFragNum] = frag1;
}
}
}
}
while (mergingStillBeingDone);
}
/* (non-Javadoc)
* @see Lucene.Net.Highlight.FragmentScorer#startFragment(Lucene.Net.Highlight.TextFragment)
*/
public virtual void StartFragment(TextFragment newFragment)
{
uniqueTermsInFragment = new System.Collections.Hashtable();
currentTextFragment = newFragment;
totalScore = 0;
}
/// <summary>Improves readability of a score-sorted list of TextFragments by merging any fragments
/// that were contiguous in the original text into one larger fragment with the correct order.
/// This will leave a "null" in the array entry for the lesser scored fragment.
///
/// </summary>
/// <param name="frag">An array of document fragments in descending score
/// </param>
private void MergeContiguousFragments(TextFragment[] frag)
{
bool mergingStillBeingDone;
if (frag.Length > 1)
{
do
{
mergingStillBeingDone = false; //initialise loop control flag
//for each fragment, scan other frags looking for contiguous blocks
for (int i = 0; i < frag.Length; i++)
{
if (frag[i] == null)
{
continue;
}
//merge any contiguous blocks
for (int x = 0; x < frag.Length; x++)
{
if (frag[x] == null)
{
continue;
}
if (frag[i] == null)
{
break;
}
TextFragment frag1 = null;
TextFragment frag2 = null;
int frag1Num = 0;
int frag2Num = 0;
int bestScoringFragNum;
int worstScoringFragNum;
//if blocks are contiguous....
if (frag[i].Follows(frag[x]))
{
frag1 = frag[x];
frag1Num = x;
frag2 = frag[i];
frag2Num = i;
}
else if (frag[x].Follows(frag[i]))
{
frag1 = frag[i];
frag1Num = i;
frag2 = frag[x];
frag2Num = x;
}
//merging required..
if (frag1 != null)
{
if (frag1.GetScore() > frag2.GetScore())
{
bestScoringFragNum = frag1Num;
worstScoringFragNum = frag2Num;
}
else
{
bestScoringFragNum = frag2Num;
worstScoringFragNum = frag1Num;
}
frag1.Merge(frag2);
frag[worstScoringFragNum] = null;
mergingStillBeingDone = true;
frag[bestScoringFragNum] = frag1;
}
}
}
}while (mergingStillBeingDone);
}
}
/// <summary> Low level api to get the most relevant (formatted) sections of the document.
/// This method has been made public to allow visibility of score information held in TextFragment objects.
/// Thanks to Jason Calabrese for help in redefining the interface.
/// </summary>
/// <param name="">tokenStream
/// </param>
/// <param name="">text
/// </param>
/// <param name="">maxNumFragments
/// </param>
/// <param name="">mergeContiguousFragments
/// </param>
/// <throws> IOException </throws>
public TextFragment[] GetBestTextFragments(TokenStream tokenStream, System.String text, bool mergeContiguousFragments, int maxNumFragments)
{
System.Collections.ArrayList docFrags = new System.Collections.ArrayList();
System.Text.StringBuilder newText = new System.Text.StringBuilder();
TextFragment currentFrag = new TextFragment(newText, newText.Length, docFrags.Count);
fragmentScorer.StartFragment(currentFrag);
docFrags.Add(currentFrag);
FragmentQueue fragQueue = new FragmentQueue(maxNumFragments);
try
{
Lucene.Net.Analysis.Token token;
System.String tokenText;
int startOffset;
int endOffset;
int lastEndOffset = 0;
textFragmenter.Start(text);
TokenGroup tokenGroup = new TokenGroup();
token = tokenStream.Next();
while ((token != null) && (token.StartOffset() < maxDocBytesToAnalyze))
{
if ((tokenGroup.numTokens > 0) && (tokenGroup.IsDistinct(token)))
{
//the current token is distinct from previous tokens -
// markup the cached token group info
startOffset = tokenGroup.matchStartOffset;
endOffset = tokenGroup.matchEndOffset;
tokenText = text.Substring(startOffset, (endOffset) - (startOffset));
System.String markedUpText = formatter.HighlightTerm(encoder.EncodeText(tokenText), tokenGroup);
//store any whitespace etc from between this and last group
if (startOffset > lastEndOffset)
{
newText.Append(encoder.EncodeText(text.Substring(lastEndOffset, (startOffset) - (lastEndOffset))));
}
newText.Append(markedUpText);
lastEndOffset = System.Math.Max(endOffset, lastEndOffset);
tokenGroup.Clear();
//check if current token marks the start of a new fragment
if (textFragmenter.IsNewFragment(token))
{
currentFrag.SetScore(fragmentScorer.GetFragmentScore());
//record stats for a new fragment
currentFrag.textEndPos = newText.Length;
currentFrag = new TextFragment(newText, newText.Length, docFrags.Count);
fragmentScorer.StartFragment(currentFrag);
docFrags.Add(currentFrag);
}
}
tokenGroup.AddToken(token, fragmentScorer.GetTokenScore(token));
// if(lastEndOffset>maxDocBytesToAnalyze)
// {
// break;
// }
token = tokenStream.Next();
}
currentFrag.SetScore(fragmentScorer.GetFragmentScore());
if (tokenGroup.numTokens > 0)
{
//flush the accumulated text (same code as in above loop)
startOffset = tokenGroup.matchStartOffset;
endOffset = tokenGroup.matchEndOffset;
tokenText = text.Substring(startOffset, (endOffset) - (startOffset));
System.String markedUpText = formatter.HighlightTerm(encoder.EncodeText(tokenText), tokenGroup);
//store any whitespace etc from between this and last group
if (startOffset > lastEndOffset)
{
newText.Append(encoder.EncodeText(text.Substring(lastEndOffset, (startOffset) - (lastEndOffset))));
}
newText.Append(markedUpText);
lastEndOffset = System.Math.Max(lastEndOffset, endOffset);
}
//Test what remains of the original text beyond the point where we stopped analyzing
if ((lastEndOffset < text.Length) && (text.Length < maxDocBytesToAnalyze))
{
//append it to the last fragment
newText.Append(encoder.EncodeText(text.Substring(lastEndOffset)));
}
currentFrag.textEndPos = newText.Length;
//sort the most relevant sections of the text
for (System.Collections.IEnumerator i = docFrags.GetEnumerator(); i.MoveNext();)
{
currentFrag = (TextFragment)i.Current;
//If you are running with a version of Lucene before 11th Sept 03
// you do not have PriorityQueue.insert() - so uncomment the code below
/*
* if (currentFrag.getScore() >= minScore)
* {
* fragQueue.put(currentFrag);
* if (fragQueue.size() > maxNumFragments)
* { // if hit queue overfull
* fragQueue.pop(); // remove lowest in hit queue
* minScore = ((TextFragment) fragQueue.top()).getScore(); // reset minScore
* }
*
*
* }
*/
//The above code caused a problem as a result of Christoph Goller's 11th Sept 03
//fix to PriorityQueue. The correct method to use here is the new "insert" method
// USE ABOVE CODE IF THIS DOES NOT COMPILE!
fragQueue.Insert(currentFrag);
}
//return the most relevant fragments
TextFragment[] frag = new TextFragment[fragQueue.Size()];
for (int i = frag.Length - 1; i >= 0; i--)
{
frag[i] = (TextFragment)fragQueue.Pop();
}
//merge any contiguous fragments to improve readability
if (mergeContiguousFragments)
{
MergeContiguousFragments(frag);
System.Collections.ArrayList fragTexts = new System.Collections.ArrayList();
for (int i = 0; i < frag.Length; i++)
{
if ((frag[i] != null) && (frag[i].GetScore() > 0))
{
fragTexts.Add(frag[i]);
}
}
frag = (TextFragment[])fragTexts.ToArray(typeof(TextFragment));
}
return(frag);
}
finally
{
if (tokenStream != null)
{
try
{
tokenStream.Close();
}
catch (System.Exception e)
{
}
}
}
}
/// <param name="fragment">
/// </param>
/// <returns> true if this fragment follows the one passed
/// </returns>
public virtual bool Follows(TextFragment fragment)
{
return(textStartPos == fragment.textEndPos);
}
/// <param name="frag2">Fragment to be merged into this one
/// </param>
public virtual void Merge(TextFragment frag2)
{
textEndPos = frag2.textEndPos;
score = System.Math.Max(score, frag2.score);
}