org.polymap.recordstore.lucene.StringValueCoder.java Source code

Introduction

Here is the source code for org.polymap.recordstore.lucene.StringValueCoder.java

Source

/* 
 * polymap.org
 * Copyright 2011, Polymap GmbH. All rights reserved.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 */
package org.polymap.recordstore.lucene;

import org.apache.commons.lang3.StringUtils;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.Field.Index;
import org.apache.lucene.document.Field.Store;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.PrefixQuery;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.search.WildcardQuery;

import org.polymap.recordstore.QueryExpression;
import org.polymap.recordstore.QueryExpression.Equal;
import org.polymap.recordstore.QueryExpression.Match;

/**
 * Interprets each and every field as a String {@link Field}. This *must* be
 * last consulted by {@link ValueCoders}. 
 *
 * @author <a href="http://www.polymap.de">Falko Brutigam</a>
 */
public class StringValueCoder implements LuceneValueCoder {

    public boolean encode(Document doc, String key, Object value, boolean indexed) {
        if (value instanceof String) {
            Field field = (Field) doc.getFieldable(key);
            if (field != null) {
                field.setValue((String) value);
            } else {
                doc.add(new Field(key, (String) value, Store.YES, indexed ? Index.NOT_ANALYZED : Index.NO));
            }
            return true;
        } else {
            return false;
        }
    }

    public Object decode(Document doc, String key) {
        return doc.get(key);
    }

    public Query searchQuery(QueryExpression exp) {
        // EQUALS
        if (exp instanceof QueryExpression.Equal) {
            Equal equalExp = (QueryExpression.Equal) exp;

            if (equalExp.value == null) {
                throw new UnsupportedOperationException(
                        "Null values are not supported for expression: Equal(String)");
            } else if (equalExp.value instanceof String) {
                return new TermQuery(new Term(equalExp.key, (String) equalExp.value));
            }
        }
        // MATCHES
        else if (exp instanceof QueryExpression.Match) {
            Match matchExp = (Match) exp;

            if (matchExp.value == null) {
                throw new UnsupportedOperationException(
                        "Null values are not supported for expression: Match(String)");
            } else if (matchExp.value instanceof String) {
                String value = (String) matchExp.value;

                // XXX properly substitute wildcard chars
                if (value.endsWith("*") && StringUtils.countMatches(value, "*") == 1
                        && StringUtils.countMatches(value, "?") == 0) {
                    return new PrefixQuery(new Term(matchExp.key, value.substring(0, value.length() - 1)));
                } else {
                    return new WildcardQuery(new Term(matchExp.key, value));
                }
            }
        }
        return null;
    }

}