linkgrammar.java

dragontoolkit用于机器学习

package dragon.nlp.tool;

import dragon.util.*;
import edu.cmu.cs.linkgrammar.*;
/**
 * <p>Link Grammar class adopted from edu.cmu.cs.linkgrammar </p>
 * <p> </p>
 * <p>Copyright: Copyright (c) 2003</p>
 * <p>Company: IST, Drexel University</p>
 * @author Davis Zhou
 * @version 1.0
 */

public class LinkGrammar {
    private Dictionary lgd;
    private ParseOptions lgp;
    private Sentence lgs;

    public LinkGrammar() {
        this(EnvVariable.getDragonHome()+ "/nlpdata/linkgrammar", 100,1);
    }

    public LinkGrammar(int maxLinkage,int maxParseTime){
        this(EnvVariable.getDragonHome()+ "/nlpdata/linkgrammar",maxLinkage,maxParseTime);
    }

    public LinkGrammar(String workDir, int maxLinkage,int maxParseTime) {
        if(!FileUtil.exist(workDir) && FileUtil.exist(EnvVariable.getDragonHome()+"/"+workDir))
                workDir=EnvVariable.getDragonHome()+"/"+workDir;
        lgd = new Dictionary(workDir+"/4.0.dict", "4.0.knowledge", "4.0.constituent-knowledge", "4.0.affix");
        lgp = new ParseOptions();
        lgp.parseOptionsSetShortLength(10);
        lgp.parseOptionsSetMaxNullCount(10);
        lgp.parseOptionsSetLinkageLimit(maxLinkage);
        lgp.parseOptionsSetMaxParseTime(maxParseTime);
    }

    public static void main(String[] args) {
        LinkGrammar lg=new LinkGrammar();
        String example="";

        for(int i=0;i<args.length;i++) example=example+" "+args[i];
        if(example.length()==0) 
        	example="I love you";
        Sentence lgs=lg.parse(example);

        if(lgs.sentenceNumLinkagesFound()<1)
        {
            lgs.sentenceDelete();
            System.out.println("No linkage was found.");
        }
        else
        {
            Linkage link=lg.getLinkage(0);
            System.out.println(link.linkagePrintDiagram());
            System.out.println(lg.getConstituentTree(link,1));
            System.out.println(lg.getConstituentTree(link,2));
            link.linkageDelete();
            lgs.sentenceDelete();
        }
        lg.close();
    }

    public Sentence parse(String sent){
        boolean resource_exhausted;

        lgs = new Sentence ( sent, lgd );
        lgs.parse(lgp);
        resource_exhausted=(lgp.parseOptionsResourcesExhausted()>0);
        if(resource_exhausted)
            lgp.parseOptionsResetResources();
        return lgs;
    }

    public Linkage getLinkage(int index)
    {
        return new Linkage(index,lgs,lgp);
    }
    
    /**
     * Print out the constituent tree
     * @param linkage the linkage returned by the getLinkage method
     * @param mode 1: nested Lisp format 2: a flat tree is displayed using brackets
     * @return the constituent tree
     */
    public String getConstituentTree(Linkage linkage, int mode){
        Constituent lgc;
        String tree;
        
        lgc= new Constituent(linkage);
        tree=lgc.printConstituentTree(linkage, mode);
        lgc.linkageFreeConstituentTree( );
        return tree;
    }

    public void close(){
        lgd.dictionaryDelete();
        lgp.parseOptionsDelete();
    }


}