source: trunk/mgpp/java/org/greenstone/mgpp/MGPPWrapper.java@ 10072

package org.greenstone.mgpp;

import java.util.Vector;

/** java wrapper class for access to mgpp in C++
 *
 * the native side implemented in MGPPWrapperImpl.cpp
 * uses MGPPQueryResult to hold the result of a query. the 
 * result of a getDocument is a String
 * uses the jni
 *
 *@see MGPPQueryResult
 */
public class MGPPWrapper {
  
    /** the query result
     * will be filled in by runQuery
     */
    protected MGPPQueryResult mgpp_query_result_=null; 
    /** pointer to c++ MGPPWrapperData class - cached indexData and queryInfo
     */
    protected long mgpp_data_ptr_=0;

    static {
    System.loadLibrary("mgppjni");
    initIDs();
    }
    
    public MGPPWrapper() {
    mgpp_query_result_ = new MGPPQueryResult();
    initCppSide();
    }

    /** initialises field and method IDs for java side to enable access on
    C++ side */
    private static native void initIDs();

    /** initialises the mgpp_data_ptr_ */
    private native boolean initCppSide();

    /** returns a document: number docnum at level level 
     * text_path path should provide
     * the absolute location of the mgpp text files eg ..../index/text/demo
     * returns the doc in utf-8
     */
    public native String getDocument(String text_path,
                     String level,
                     long docnum );

    /** the public method - converts between utf-8 and unicode
     */
    // public String getDocument(String text_path,
    //            String level,
    //            long docnum ) {

    //String utf8_doc = getUtF8Document(base_dir, text_path, level, docnum);
    
    /** load up the data structure for index 
     * - maintains state between requests as can be slow  
     * index_path should provide
     * the absolute location of the mgpp index files eg ..../index/tt/demo 
     */
    public native boolean loadIndexData(String index_path);
    /** unloads the data */
    public native boolean unloadIndexData();

    // query param methods

    /** if on=true, sets default stemming on  - its off by default*/
    public native void setStem(boolean on);
    /** if on=true, sets default casefolding on - its off by default */
    public native void setCase(boolean on);
    /** default is 50 */
    public native void setMaxDocs(int num);
    /** if on=true, sorts by rank, otherwise returns in build order - 
    default is on */
    public native void setSortByRank(boolean on);
    /** if on=true, a query returns term freq info - default is on */
    public native void setReturnTerms(boolean on);
    /** sets the granularity of the  query  - default 'Document' */
    public native void setQueryLevel(String level);
    /** sets the granularity of the result - default 'Document' */
    public native void setReturnLevel(String level);
    /** sets the default boolean operator - AND(=1)/OR(=0) */
    public native void setMatchMode(int mode);

    /** returns a string with all the current query param settings */
    public native String getQueryParams();

    /** actually carry out the query. Use the set methods to set any query
    params 
    * writes the result to query_result
    */
    public native void runQuery(String query_string); 

    /** get the result out of the wrapper */
    public MGPPQueryResult getQueryResult() {
    return mgpp_query_result_;
    }
    
}