org.opencypher.gremlin.client.CypherResultSet Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of cypher-gremlin-server-client Show documentation
Gremlin Server client wrapper that can send Cypher queries to a Cypher-enabled Gremlin Server
The newest version!
/*
 * Copyright (c) 2018-2019 "Neo4j, Inc." [https://neo4j.com]
 *
 * 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 org.opencypher.gremlin.client;

import static java.util.Spliterator.IMMUTABLE;
import static java.util.Spliterator.NONNULL;
import static java.util.Spliterators.spliteratorUnknownSize;
import static java.util.stream.Collectors.toList;

import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Spliterator;
import java.util.function.Function;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
import org.apache.tinkerpop.gremlin.driver.Result;

/**
 * A Gremlin query result iterator wrapper.
 * 
 * In the case of most {@link CypherGremlinClient} configurations,
 * instances of this class wrap a Gremlin {@link org.apache.tinkerpop.gremlin.driver.ResultSet} iterator,
 * so this class is not thread-safe, by extension.
 *
 * @see CypherGremlinClient
 */
public final class CypherResultSet implements Iterable> {

    private final Iterator resultIterator;
    private Function> returnNormalizer;

    CypherResultSet(Iterator resultIterator) {
        this(resultIterator, CypherResultSet::castToMap);
    }

    CypherResultSet(Iterator resultIterator, Function> returnNormalizer) {
        this.resultIterator = resultIterator;
        this.returnNormalizer = returnNormalizer;
    }

    /**
     * Waits for all query results to be received by the client and collects them in a list.
     *
     * @return list of all query results
     */
    public List> all() {
        return stream().collect(toList());
    }

    /**
     * Creates a spliterator over query results.
     *
     * @return a spliterator over query results
     */
    @Override
    public Spliterator> spliterator() {
        return spliteratorUnknownSize(iterator(), NONNULL | IMMUTABLE);
    }

    /**
     * Returns a sequential stream of query results.
     *
     * @return a sequential stream of query results
     */
    public Stream> stream() {
        return StreamSupport.stream(spliterator(), false);
    }

    /**
     * Returns a blocking iterator of the items streaming from the server to the client.
     *
     * @return query results iterator
     */
    @Override
    public Iterator> iterator() {
        return new Iterator>() {
            @Override
            public boolean hasNext() {
                return resultIterator.hasNext();
            }

            @Override
            public Map next() {
                Result result = resultIterator.next();
                Object row = result.getObject();
                return returnNormalizer.apply(row);
            }
        };
    }

    @SuppressWarnings("unchecked")
    private static Map castToMap(Object e) {
        return (Map) e;
    }
}