com.tsgrp.solr.handler.NYPhilTagAutoCompleteHandler.java Source code

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Here is the source code for com.tsgrp.solr.handler.NYPhilTagAutoCompleteHandler.java

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/*
 * Copyright (C) Technology Services Group, Inc.
 *
 * Licensed under the Mozilla Public License version 1.1 
 * with a permitted attribution clause. You may obtain a
 * copy of the License at
 *
 *   http://www.tsgrp.com/legal/license
 *
 * 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.tsgrp.solr.handler;

import java.util.regex.Pattern;

import org.apache.lucene.queryParser.ParseException;
import org.apache.lucene.queryParser.QueryParser;
import org.apache.solr.common.params.CommonParams;
import org.apache.solr.common.params.FacetParams;
import org.apache.solr.common.params.SolrParams;
import org.apache.solr.common.util.NamedList;
import org.apache.solr.handler.component.SearchHandler;
import org.apache.solr.request.SolrQueryRequest;
import org.apache.solr.request.SolrQueryResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author Phil MacCart, Technology Services Group
 * @version 1.0
 *
 * <h2>Modification History</h2>
 * <ul>
 *      <li>Feb 7, 2012 (Phil MacCart) Created.</li>
 * </ul>
 * <p>Copyright &copy; 2012 Technology Services Group, Inc.</p>
 */
public class NYPhilTagAutoCompleteHandler extends SearchHandler {
    private static final Logger logger = LoggerFactory.getLogger(NYPhilTagAutoCompleteHandler.class);

    private static final String PARAM_VALUE = "value";
    private static final String PARAM_CALLBACK = "callback";

    // regex used to remove all non-alphanumeric chars from the query input so we can 
    // still use wildcard searches without need to use an edge n-gram filter factory
    private static final Pattern QUERY_TERM_REGEX = Pattern.compile("[\\W]");

    /*
     * @see org.apache.solr.handler.component.SearchHandler#handleRequestBody(org.apache.solr.request.SolrQueryRequest, org.apache.solr.request.SolrQueryResponse)
     */
    @Override
    public void handleRequestBody(SolrQueryRequest req, SolrQueryResponse res)
            throws Exception, ParseException, InstantiationException, IllegalAccessException {
        NamedList<Object> params = req.getParams().toNamedList();

        params.add(CommonParams.ROWS, 0);
        params.add(FacetParams.FACET, true);
        params.add(FacetParams.FACET_FIELD, NYPhilSolrConstants.NPT_CONTENT_FACET);
        params.add(FacetParams.FACET_MINCOUNT, 1);
        params.add(FacetParams.FACET_SORT, FacetParams.FACET_SORT_INDEX);
        params.add(CommonParams.HEADER_ECHO_PARAMS, "explicit");
        params.add(CommonParams.WT, "json");
        params.add("json.nl", "map");

        String query = (String) params.get(PARAM_VALUE);
        if (query == null || query.length() == 0) {
            query = "*";
        } else {
            query = QueryParser.escape(query.toLowerCase());
        }

        String[] queryTerms = query.split(" ");

        // wrap our query term in parentheses to allow searching on terms separated by whitespace
        StringBuffer q = new StringBuffer();

        // for each query term, require the term with a trailing wildcard match
        for (String queryTerm : queryTerms) {

            // remove all non-alphanumeric chars from the query term
            queryTerm = QUERY_TERM_REGEX.matcher(queryTerm.toLowerCase()).replaceAll("");
            q.append("+").append(NYPhilSolrConstants.NPT_CONTENT_ESC).append(":")
                    .append(QueryParser.escape(queryTerm)).append("* ");
        }
        q.append("+").append(NYPhilSolrConstants.NPT_STATUS_ESC).append(":")
                .append(NYPhilSolrConstants.STATUS_APPROVED);

        params.add(CommonParams.Q, q.toString());

        if (logger.isDebugEnabled()) {
            logger.debug("Autocomplete Query: " + q.toString());
        }

        String cb = (String) params.get(PARAM_CALLBACK);
        if (cb != null && cb.length() > 0) {
            params.add("json.wrf", cb);
        }

        req.setParams(SolrParams.toSolrParams(params));

        super.handleRequestBody(req, res);
    }

}