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

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package de.aitools.aq.invertedindex.usage;

import java.io.File;
import java.nio.ByteBuffer;
import java.util.Scanner;

import com.google.protobuf.InvalidProtocolBufferException;

import de.aitools.aq.invertedindex.core.Configuration;
import de.aitools.aq.invertedindex.core.Configuration.KeySorting;
import de.aitools.aq.invertedindex.core.Indexer;
import de.aitools.aq.invertedindex.core.Postlist;
import de.aitools.aq.invertedindex.core.Searcher;
import de.aitools.aq.invertedindex.usage.MyProtobufObject.Person;
import de.aitools.aq.util.Memory;
import de.aitools.aq.util.Record;
import de.aitools.aq.value.Value;
import de.aitools.aq.value.single.SingleBuffer;
import de.aitools.aq.value.single.SingleString;

public class UsingSingleBuffer {

        // -------------------------------------------------------------------------
        // Generate the Java code for your Protobuf object
        // -------------------------------------------------------------------------
        
        // 1. Create the schema of your object (MyProtobufObject.proto text file).
        //
        // option java_package = "de.aitools.aq.invertedindex.usage";
        //
        // message Person {
        //        required int32 id = 1;
        //        required string name = 2;
        //        optional string email = 3;
        // }
        //
        // 2. Compile that text file to generate the Java code of this object.
        //
        // $ protoc --java_out=. MyProtobufObject.proto
        //
        // 3. Import the generated MyProtobufObject.java file into your project.

        public static void main(String[] args)
        throws InvalidProtocolBufferException {
                
                // ---------------------------------------------------------------------
                // Setup the Indexer
                // ---------------------------------------------------------------------
                Configuration config = new Configuration();
                config.setIndexDirectory(new File("/path/to/your/index"));
                config.setKeySorting(KeySorting.UNSORTED);      // optional, see doc
                config.setMaxMemoryUsage(Memory.MB1024);        // optional, see doc
                // Note config.setValueSorting(...) has no effect
                
                // ---------------------------------------------------------------------
                // Instantiate a new Indexer
                // ---------------------------------------------------------------------
                Class<SingleBuffer> valueClass = SingleBuffer.class;
                Indexer<SingleBuffer> indexer = Indexer.open(valueClass, config);
                
                // ---------------------------------------------------------------------
                // Create some Person objects and put them into the indexer
                // ---------------------------------------------------------------------
                for (int i = 0; i != Short.MAX_VALUE; ++i) {
                        // Create some key
                        String key = "key" + (i % Byte.MAX_VALUE);
                        // Create some value
                        Person.Builder builder = Person.newBuilder();
                        builder.setName("John Doe #" + i);
                        builder.setEmail("john.doe@uni-weimar.de #" + i);
                        builder.setId(i);
                        Person person = builder.build();
                        SingleBuffer value = new SingleBuffer(person.toByteArray());
                        // Create and put the record
                        indexer.put(new Record<SingleBuffer>(key, value));
                }
                
                indexer.index(); // be patient ...
                
                // ---------------------------------------------------------------------
                // Open the inverted index
                // ---------------------------------------------------------------------
                Searcher<SingleBuffer> searcher = Searcher.open(valueClass, config);
                
                // ---------------------------------------------------------------------
                // Search the inverted index
                // ---------------------------------------------------------------------
                Scanner scanner = new Scanner(System.in);
                while (true) {
                        System.out.print("Enter key (type 'q' to exit) : ");
                        String key = scanner.nextLine();
                        if (key.equals("q")) break;
                        Postlist<SingleBuffer> postlist = searcher.search(key);
                        if (postlist != null) {
                                for (SingleBuffer value : postlist) {
                                        Person person = Person.parseFrom(value.getBuffer().array());
                                        System.out.println(person);
                                }
                                postlist.deleteNative(); // This is essential, do not forget !
                        } else {
                                System.out.println("Nothing found");
                        }
                }
                searcher.close();
        }

}

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