I'm trying to create a summarizer in Java. I'm using the Stanford Log-linear Part-Of-Speech Tagger to tag the words, and then, for certain tags, I'm scoring the sentence and finally in the summary, I'm printing sentences with a high score value. Here's the code:
MaxentTagger tagger = new MaxentTagger("taggers/bidirectional-distsim-wsj-0-18.tagger");
BufferedReader reader = new BufferedReader( new FileReader ("C:\\Summarizer\\src\\summarizer\\testing\\testingtext.txt"));
String line = null;
int score = 0;
StringBuilder stringBuilder = new StringBuilder();
File tempFile = new File("C:\\Summarizer\\src\\summarizer\\testing\\tempFile.txt");
Writer writerForTempFile = new BufferedWriter(new FileWriter(tempFile));
String ls = System.getProperty("line.separator");
while( ( line = reader.readLine() ) != null )
{
stringBuilder.append( line );
stringBuilder.append( ls );
String tagged = tagger.tagString(line);
Pattern pattern = Pattern.compile("[.?!]"); //Find new line
Matcher matcher = pattern.matcher(tagged);
while(matcher.find())
{
Pattern tagFinder = Pattern.compile("/JJ"); // find adjective tag
Matcher tagMatcher = tagFinder.matcher(matcher.group());
while(tagMatcher.find())
{
score++; // increase score of sentence for every occurence of adjective tag
}
if(score > 1)
writerForTempFile.write(stringBuilder.toString());
score = 0;
stringBuilder.setLength(0);
}
}
reader.close();
writerForTempFile.close();
The above code isn't working. Although, if I cut my work and generate score for every line(not sentence),it works. But summaries aren't generated that way,are they? Here's the code for that: (all the declarations being the same as above)
while( ( line = reader.readLine() ) != null )
{
stringBuilder.append( line );
stringBuilder.append( ls );
String tagged = tagger.tagString(line);
Pattern tagFinder = Pattern.compile("/JJ"); // find adjective tag
Matcher tagMatcher = tagFinder.matcher(tagged);
while(tagMatcher.find())
{
score++; //increase score of line for every occurence of adjective tag
}
if(score > 1)
writerForTempFile.write(stringBuilder.toString());
score = 0;
stringBuilder.setLength(0);
}
EDIT 1:
Information regarding what the MaxentTagger does. A sample code to show it's functioning :
import java.io.IOException;
import edu.stanford.nlp.tagger.maxent.MaxentTagger;
public class TagText {
public static void main(String[] args) throws IOException,
ClassNotFoundException {
// Initialize the tagger
MaxentTagger tagger = new MaxentTagger(
"taggers/bidirectional-distsim-wsj-0-18.tagger");
// The sample string
String sample = "This is a sample text";
// The tagged string
String tagged = tagger.tagString(sample);
// Output the result
System.out.println(tagged);
}
}
Output:
This/DT is/VBZ a/DT sample/NN sentence/NN
EDIT 2:
Modified code using BreakIterator to find sentence breaks. Yet the problem is persisting.
while( ( line = reader.readLine() ) != null )
{
stringBuilder.append( line );
stringBuilder.append( ls );
String tagged = tagger.tagString(line);
BreakIterator bi = BreakIterator.getSentenceInstance();
bi.setText(tagged);
int end, start = bi.first();
while ((end = bi.next()) != BreakIterator.DONE)
{
String sentence = tagged.substring(start, end);
Pattern tagFinder = Pattern.compile("/JJ");
Matcher tagMatcher = tagFinder.matcher(sentence);
while(tagMatcher.find())
{
score++;
}
scoreTracker.add(score);
if(score > 1)
writerForTempFile.write(stringBuilder.toString());
score = 0;
stringBuilder.setLength(0);
start = end;
}
Finding sentence breaks can be a bit more involved than just looking for [.?!], consider using BreakIterator.getSentenceInstance()
Its performance is actually quite similar to LingPipe's (more complex) implementation, and better than the one in OpenNLP (from my own testing, at least).
BreakIterator bi = BreakIterator.getSentenceInstance();
bi.setText(text);
int end, start = bi.first();
while ((end = bi.next()) != BreakIterator.DONE) {
String sentence = text.substring(start, end);
start = end;
}
I think this is what you're looking for:
Pattern tagFinder = Pattern.compile("/JJ");
BufferedReader reader = getMyReader();
String line = null;
while ((line = reader.readLine()) != null) {
BreakIterator bi = BreakIterator.getSentenceInstance();
bi.setText(line);
int end, start = bi.first();
while ((end = bi.next()) != BreakIterator.DONE) {
String sentence = line.substring(start, end);
String tagged = tagger.tagString(sentence);
int score = 0;
Matcher tag = tagFinder.matcher(tagged);
while (tag.find())
score++;
if (score > 1)
writerForTempFile.println(sentence);
start = end;
}
}