import java.io.IOException;
import java.io.PrintStream;

import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.StringField;
import org.apache.lucene.document.Field.Store;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.IndexableField;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.MatchAllDocsQuery;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.store.RAMDirectory;
import org.apache.lucene.util.Version;

public class ReindexTest {
    static RAMDirectory dir = new RAMDirectory();
    static Version version = Version.LUCENE_4_10_0;
    static IndexWriterConfig config = new IndexWriterConfig(version, new StandardAnalyzer());
    static IndexWriter iw;

    static String teststring = "abc def";

    public static void main(String[] args) throws Exception {
        iw = new IndexWriter(dir, config);

        Document doc = new Document();
        doc.add(new StringField("a", teststring, Store.YES));
        doc.add(new StringField("b", "a", Store.YES));
        iw.addDocument(doc);

        Term term = new Term("a", teststring);
        System.out.println("Term query");
        for (Document docs : search(term))
            printDocument(docs, System.out);

        doc = search(term)[0];
        doc.removeField("b");
        doc.add(new StringField("b", "b", Store.YES));
        iw.updateDocument(term, doc);

        iw.commit();
        iw.waitForMerges();
        iw.close();

        iw = new IndexWriter(dir, new IndexWriterConfig(version, new StandardAnalyzer()));

        System.out.println("All docs");
        for (Document docs : search(new MatchAllDocsQuery()))
            printDocument(docs, System.out);

        System.out.println("Term query");
        for (Document docs : search(term))
            printDocument(docs, System.out);
    }

    public static Document[] search(Term t) throws IOException {
        TermQuery q = new TermQuery(t);
        return search(q);
    }

    public static Document[] search(Query q) throws IOException {
        DirectoryReader reader = DirectoryReader.open(iw, true);
        IndexSearcher search = new IndexSearcher(reader);
        ScoreDoc[] results = search.search(q, 100).scoreDocs;

        Document[] docs = new Document[results.length];

        for (int i = 0; i < docs.length; i++)
            docs[i] = search.doc(results[i].doc);

        return docs;
    }

    public static void printDocument(Document doc, PrintStream output) {
        for (IndexableField field : doc.getFields()) {
            output.println(field.toString());
        }
        output.println("------------------------------------");
    }

}