org.archive.nutchwax.tools.GetUniqFieldValues.java Source code

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Here is the source code for org.archive.nutchwax.tools.GetUniqFieldValues.java

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/*
 * Copyright (C) 2008 Internet Archive.
 * 
 * This file is part of the archive-access tools project
 * (http://sourceforge.net/projects/archive-access).
 * 
 * The archive-access tools are free software; you can redistribute them and/or
 * modify them under the terms of the GNU Lesser Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or any
 * later version.
 * 
 * The archive-access tools are distributed in the hope that they will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
 * Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser Public License along with
 * the archive-access tools; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package org.archive.nutchwax.tools;

import java.io.File;
import java.util.Iterator;
import java.util.Set;
import java.util.HashSet;
import java.util.Collection;

import org.apache.lucene.index.IndexReader;

/**
 * A quick-n-dirty command-line utility to get the unique values for a
 * field in an index and print them to stdout.
 */
public class GetUniqFieldValues {
    public static void main(String[] args) throws Exception {
        String fieldName = "";
        String indexDir = "";

        if (args.length == 2) {
            fieldName = args[0];
            indexDir = args[1];
        }

        if (!(new File(indexDir)).exists()) {
            usageAndExit();
        }

        dumpUniqValues(fieldName, indexDir);
    }

    private static void dumpUniqValues(String fieldName, String indexDir) throws Exception {
        IndexReader reader = IndexReader.open(indexDir);

        Collection fieldNames = reader.getFieldNames(IndexReader.FieldOption.ALL);

        if (!fieldNames.contains(fieldName)) {
            System.out.println("Field not in index: " + fieldName);
            System.exit(2);
        }

        int numDocs = reader.numDocs();
        Set<String> values = new HashSet<String>();

        for (int i = 0; i < numDocs; i++) {
            values.add(reader.document(i).get(fieldName));
        }

        for (String v : values) {
            System.out.println(v);
        }

    }

    private static void usageAndExit() {
        System.out.println("Usage: GetUniqFieldValues field index");
        System.exit(1);
    }
}