WildcardCondition.java

/*
 * Copyright 2014, Stratio.
 * Modification and adapations - Copyright 2014, Tuplejump Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.tuplejump.stargate.lucene.query;

import com.tuplejump.stargate.lucene.Options;
import com.tuplejump.stargate.lucene.Properties;
import com.tuplejump.stargate.lucene.Type;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.WildcardQuery;
import org.apache.lucene.util.automaton.Automaton;
import org.codehaus.jackson.annotate.JsonCreator;
import org.codehaus.jackson.annotate.JsonProperty;

/**
 * Implements the wildcard search query. Supported wildcards are {@code *}, which matches any character sequence
 * (including the empty one), and {@code ?}, which matches any single character. '\' is the escape character.
 *
 * Note this query can be slow, as it needs to iterate over many terms. In order to prevent extremely slow
 * WildcardQueries, a Wildcard term should not start with the wildcard {@code *}.
 */
public class WildcardCondition extends Condition implements Selector {

    /**
     * The field name
     */
    private final String field;

    /**
     * The field value
     */
    private final String value;

    /**
     * Constructor using the field name and the value to be matched.
     *
     * @param boost The boost for this query clause. Documents matching this clause will (in addition to the normal
     *              weightings) have their score multiplied by {@code boost}. If {@code null}, then DEFAULT_BOOST
     *              is used as default.
     * @param field the field name.
     * @param value the field value.
     */
    @JsonCreator
    public WildcardCondition(@JsonProperty("boost") Float boost,
                             @JsonProperty("field") String field,
                             @JsonProperty("value") String value) {
        super(boost);

        this.field = field != null ? field.toLowerCase() : null;
        this.value = value;
    }

    @Override
    public Automaton getAutomaton(Options options) {
        Term term = new Term(field, value);
        return WildcardQuery.toAutomaton(term);
    }

    /**
     * Returns the field name.
     *
     * @return the field name.
     */
    public String getField() {
        return field;
    }

    /**
     * Returns the field value.
     *
     * @return the field value.
     */
    public String getValue() {
        return value;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public Query query(Options schema) {

        if (field == null || field.trim().isEmpty()) {
            throw new IllegalArgumentException("Field name required");
        }
        if (value == null || value.trim().isEmpty()) {
            throw new IllegalArgumentException("Field value required");
        }

        Query query;
        Properties properties = schema.getProperties(field);
        Type fieldType = properties != null ? properties.getType() : Type.text;
        if (fieldType.isCharSeq()) {
            Term term = new Term(field, value);
            query = new WildcardQuery(term);
        } else {
            String message = String.format("Wildcard queries are not supported by %s mapper", fieldType);
            throw new UnsupportedOperationException(message);
        }
        return query;
    }

    @Override
    public String getType() {
        return "wildcard";
    }


    /**
     * {@inheritDoc}
     */
    @Override
    public String toString() {
        StringBuilder builder = new StringBuilder();
        builder.append(getClass().getSimpleName());
        builder.append(" [boost=");
        builder.append(boost);
        builder.append(", field=");
        builder.append(field);
        builder.append(", value=");
        builder.append(value);
        builder.append("]");
        return builder.toString();
    }

}