stack/corepersistence/graph/src/main/java/org/apache/usergrid/persistence/graph/serialization/impl/EdgesObservableImpl.java

/*
 *
 *  * Licensed to the Apache Software Foundation (ASF) under one or more
 *  *  contributor license agreements.  The ASF licenses this file to You
 *  * 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.  For additional information regarding
 *  * copyright in this work, please see the NOTICE file in the top level
 *  * directory of this distribution.
 *
 */
package org.apache.usergrid.persistence.graph.serialization.impl;


import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.usergrid.persistence.graph.Edge;
import org.apache.usergrid.persistence.graph.GraphManager;
import org.apache.usergrid.persistence.graph.SearchByEdgeType;
import org.apache.usergrid.persistence.graph.impl.SimpleSearchByEdgeType;
import org.apache.usergrid.persistence.graph.impl.SimpleSearchByIdType;
import org.apache.usergrid.persistence.graph.impl.SimpleSearchEdgeType;
import org.apache.usergrid.persistence.graph.serialization.EdgesObservable;
import org.apache.usergrid.persistence.model.entity.Id;

import com.google.common.base.Optional;

import rx.Observable;


/**
 * Emits the edges that are edges from the specified source node
 */
public class EdgesObservableImpl implements EdgesObservable {

    private static final Logger logger = LoggerFactory.getLogger( EdgesObservableImpl.class );


    public EdgesObservableImpl() {

    }


    /**
     * Get all edges from the source
     */
    @Override
    public Observable<Edge> edgesFromSourceDescending(final GraphManager gm, final Id sourceNode, boolean filterMarked) {
        final Observable<String> edgeTypes =
            gm.getEdgeTypesFromSource( new SimpleSearchEdgeType( sourceNode, null, null ) );

        return edgeTypes.flatMap(  edgeType -> {

                if (logger.isTraceEnabled()) {
                    logger.trace("Loading edges of edgeType {} from {}", edgeType, sourceNode);
                }

                return gm.loadEdgesFromSource(
                    new SimpleSearchByEdgeType( sourceNode, edgeType, Long.MAX_VALUE, SearchByEdgeType.Order.DESCENDING,
                        Optional.<Edge>absent(), filterMarked ) );
        } );
    }


    @Override
    public Observable<Edge> edgesFromSourceDescending( final GraphManager gm, final Id sourceNode,
                                                       final Optional<String> edgeTypeInput, final Optional<Edge> resume  ) {



        final Observable<String> edgeTypes = edgeTypeInput.isPresent()? Observable.just( edgeTypeInput.get() ):
                  gm.getEdgeTypesFromSource( new SimpleSearchEdgeType( sourceNode, null, null ) );


        return edgeTypes.flatMap(  edgeType -> {

                if (logger.isTraceEnabled()) {
                    logger.trace("Loading edges of edgeType {} from {}", edgeType, sourceNode);
                }

                return gm.loadEdgesFromSource(
                    new SimpleSearchByEdgeType( sourceNode, edgeType, Long.MAX_VALUE, SearchByEdgeType.Order.DESCENDING,
                       resume ) );
        } );
    }


    @Override
    public Observable<Edge> getEdgesFromSource( final GraphManager gm, final Id sourceNode, final String targetType ) {

        final Observable<String> edgeTypes =
            gm.getEdgeTypesFromSource( new SimpleSearchEdgeType( sourceNode, null, null ) );


        return edgeTypes.flatMap( edgeType -> {

            if (logger.isTraceEnabled()) {
                logger.trace("Loading edges of edgeType {} from {}", edgeType, sourceNode);
            }

            return gm.loadEdgesFromSourceByType(
                new SimpleSearchByIdType( sourceNode, edgeType, Long.MAX_VALUE, SearchByEdgeType.Order.DESCENDING,
                    targetType, null ) );
        } );
    }


    /**
     * Get all edges from the source
     */
    @Override
    public Observable<Edge> edgesToTarget(final GraphManager gm, final Id targetNode, boolean filterMarked) {

        return gm.getEdgeTypesToTarget( new SimpleSearchEdgeType( targetNode, null, null ) )
            .flatMap( edgeType -> {
                if (logger.isTraceEnabled()) {
                    logger.trace("Loading edges of edgeType {} to {}", edgeType, targetNode);
                }
            return gm.loadEdgesToTarget(
                new SimpleSearchByEdgeType( targetNode, edgeType, Long.MAX_VALUE, SearchByEdgeType.Order.DESCENDING,
                    Optional.<Edge>absent(), filterMarked ) );
        } );
    }


}