/home/palakars/workspace-inprogress/code-in-progress/aitools3/aitools3-aq-invertedindex2-java/src/de/aitools/aq/invertedindex/core/Searcher.java

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// Copyright (C) 2011 webis.de. All rights reserved.
package de.aitools.aq.invertedindex.core;

import com.sun.jna.Native;
import com.sun.jna.Pointer;

import de.aitools.aq.check.A;
import de.aitools.aq.invertedindex.core.Configuration.ConfigurationImpl;
import de.aitools.aq.invertedindex.core.Postlist.Head;
import de.aitools.aq.invertedindex.core.Properties.PropertiesImpl;
import de.aitools.aq.util.ToAsciiEncoder;
import de.aitools.aq.value.Value;

public class Searcher<V extends Value> {
        
        static {
                Native.register(Configuration.NATIVE_LIB);
                System.out.println(Configuration.NATIVE_LIB + " loaded");
        }
        
        public static <V extends Value> Searcher<V>
        open(Class<V> clazz, Configuration config) {
                A.CHECK_NOT_NULL(clazz, config);
                Properties props = new Properties();
                Pointer nativeSearcher = searcher_open(
                                Value.getNativeTypeId(clazz), config.impl, props.impl);
                if (nativeSearcher == null) {
                        throw new RuntimeException("Cannot create native Searcher");
                }
                return new Searcher<V>(nativeSearcher, clazz, props);
        }

        private Searcher(Pointer nativeSearcher, Class<V> clazz, Properties props) {
                A.CHECK_NOT_NULL(nativeSearcher, clazz, props);
                this.nativeSearcher = nativeSearcher;
                this.clazz = clazz;
                this.props = props;
        }
        
        public void close() {
                searcher_close(nativeSearcher);
                nativeSearcher = null;
        }
        
        public boolean contains(String key) {
                return getHead(key) != null;
        }
        
        @Override
        protected void finalize() throws Throwable {
                close();
                super.finalize();
        }
        
        public Postlist.Head getHead(String key) {
                A.CHECK_NOT_NULL(key);
                key = ToAsciiEncoder.encode(key);
                Postlist.Head head = new Postlist.Head();
                if (!searcher_search_head(nativeSearcher, key, head)) head = null;
                return head;
        }
        
        public Properties getProperties() {
                return props;
        }
        
        public Postlist<V> search(String key) {
                return search(key, Integer.MAX_VALUE);
        }
        
        public Postlist<V> search(String key, int num) {
                return search(key, 0, num);
        }
        
        public Postlist<V> search(String key, int begin, int num) {
                A.CHECK_NOT_NULL(key);
                key = ToAsciiEncoder.encode(key);
                Postlist.Head head = new Postlist.Head();
                Pointer nativePostlist = searcher_search_postlist(
                                nativeSearcher, key, begin, num, head);
                return nativePostlist != null ?
                                new Postlist<V>(clazz, nativePostlist, head) : null;
        }
        
        private Pointer nativeSearcher;
        private Properties props;
        private Class<V> clazz;
        
        // -------------------------------------------------------------------------
        // JNA functions - TOUCH AND DIE
        // -------------------------------------------------------------------------
        
        private static native Pointer searcher_open(
                        int type_id, ConfigurationImpl config, PropertiesImpl props);
        private native void searcher_close(Pointer raw_searcher);
        private native boolean searcher_search_head(
                        Pointer raw_searcher, String key, Postlist.Head head);
        private native Pointer searcher_search_postlist(Pointer raw_searcher,
                        String key, int begin, int num, Postlist.Head header);
}

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