org.polymap.rhei.fulltext.SearchDispatcher.java Source code

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Here is the source code for org.polymap.rhei.fulltext.SearchDispatcher.java

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/* 
 * polymap.org
 * Copyright (C) 2014, Falko Brutigam. 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 3.0 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.rhei.fulltext;

import static com.google.common.collect.Iterables.all;
import static com.google.common.collect.Iterables.concat;
import static com.google.common.collect.Iterables.limit;
import static com.google.common.collect.Iterables.transform;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;

import org.json.JSONObject;

import org.apache.commons.lang3.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.google.common.base.Function;
import com.google.common.base.Predicate;

/**
 * Allows multiple {@link FulltextIndex} instances to be queried.
 * 
 * @author <a href="http://www.polymap.de">Falko Brutigam</a>
 */
public class SearchDispatcher implements FulltextIndex {

    private static Log log = LogFactory.getLog(SearchDispatcher.class);

    private List<FulltextIndex> searchers = new ArrayList();

    private ExecutorService executorService;

    public SearchDispatcher(FulltextIndex[] indexes) {
        searchers.addAll(Arrays.asList(indexes));
    }

    @Override
    public void close() {
        assert !isClosed() : "FulltextIndex is closed already.";
        for (FulltextIndex index : searchers) {
            index.close();
        }
        searchers = null;
    }

    @Override
    public boolean isClosed() {
        return searchers == null;
    }

    @Override
    protected void finalize() throws Throwable {
        if (!isClosed()) {
            close();
        }
    }

    @Override
    public boolean isEmpty() {
        return all(searchers, new Predicate<FulltextIndex>() {
            public boolean apply(FulltextIndex input) {
                return input.isEmpty();
            }
        });
    }

    @Override
    public Iterable<String> propose(final String term, final int maxResults, final String field) throws Exception {
        // call searches in separate threads
        // XXX score results
        List<Future<List<String>>> results = new ArrayList();
        for (final FulltextIndex searcher : searchers) {
            results.add(executorService.submit(new Callable<List<String>>() {
                @Override
                public List<String> call() throws Exception {
                    log.info("Searcher started: " + searcher.getClass().getSimpleName());
                    Iterable<String> records = searcher.propose(term, maxResults, field);

                    // use real list (not Iterables) in order to make sure
                    // this processing is done inside the thread
                    List<String> result = new ArrayList(maxResults);
                    Iterator<String> it = records.iterator();
                    while (it.hasNext() && result.size() <= maxResults) {
                        String record = it.next();
                        // has the record any result anyway?
                        if (StringUtils.containsNone(term, SEPARATOR_CHARS)
                                || !search(record, 1).iterator().hasNext()) {
                            result.add(record);
                        }
                    }
                    return result;
                }
            }));
        }

        // wait for threads; concat all records
        return concat(transform(results, new Function<Future<List<String>>, List<String>>() {
            public List<String> apply(Future<List<String>> future) {
                try {
                    return future.get();
                } catch (Exception e) {
                    log.warn("", e);
                    return new ArrayList();
                }
            }
        }));
    }

    @Override
    public Iterable<JSONObject> search(final String term, final int maxResults) throws Exception {
        // call searches in separate threads
        // XXX score results
        List<Future<Iterable<JSONObject>>> results = new ArrayList();
        for (final FulltextIndex searcher : searchers) {
            results.add(executorService.submit(new Callable<Iterable<JSONObject>>() {
                @Override
                public Iterable<JSONObject> call() throws Exception {
                    log.debug("Searcher started: " + searcher.getClass().getSimpleName());
                    return searcher.search(term, maxResults);
                }
            }));
        }

        // wait for threads; concat all SearchResults, limit to maxResults
        return limit(concat(transform(results, new Function<Future<Iterable<JSONObject>>, Iterable<JSONObject>>() {
            public Iterable<JSONObject> apply(Future<Iterable<JSONObject>> future) {
                try {
                    return future.get();
                } catch (Exception e) {
                    log.warn("", e);
                    return new ArrayList();
                }
            }
        })), maxResults);
    }

}