[GitHub] storm pull request #1656: STORM-2057 Support JOIN statement in Storm SQL

[harshach <gi...@git.apache.org>]

Github user harshach commented on a diff in the pull request:

    https://github.com/apache/storm/pull/1656#discussion_r77939709
  
    --- Diff: storm-core/src/jvm/org/apache/storm/trident/operation/impl/PreservingFieldsOrderJoinerMultiReducer.java ---
    @@ -0,0 +1,175 @@
    +/**
    + * Licensed to the Apache Software Foundation (ASF) under one
    + * or more contributor license agreements.  See the NOTICE file
    + * distributed with this work for additional information
    + * regarding copyright ownership.  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.
    + */
    +package org.apache.storm.trident.operation.impl;
    +
    +import org.apache.storm.trident.JoinType;
    +import org.apache.storm.trident.operation.GroupedMultiReducer;
    +import org.apache.storm.trident.operation.TridentCollector;
    +import org.apache.storm.trident.operation.TridentMultiReducerContext;
    +import org.apache.storm.trident.tuple.ComboList;
    +import org.apache.storm.trident.tuple.TridentTuple;
    +import org.apache.storm.tuple.Fields;
    +
    +import java.util.ArrayList;
    +import java.util.List;
    +import java.util.Map;
    +
    +public class PreservingFieldsOrderJoinerMultiReducer implements GroupedMultiReducer<JoinState> {
    +    List<JoinType> _types;
    +    List<Fields> _sideFields;
    +    List<Fields> _joiningFields;
    +    List<Fields> _originFields;
    +    int _numGroupFields;
    +    ComboList.Factory _factory;
    +
    +
    +    public PreservingFieldsOrderJoinerMultiReducer(List<JoinType> types, int numGroupFields, List<Fields> origins,
    +                                                   List<Fields> joins, List<Fields> sides) {
    +        _types = types;
    +        _originFields = origins;
    +        _joiningFields = joins;
    +        _sideFields = sides;
    +
    +        // we already checked this
    +        _numGroupFields = numGroupFields;
    +    }
    +
    +    @Override
    +    public void prepare(Map conf, TridentMultiReducerContext context) {
    +        int[] sizes = new int[_originFields.size()];
    +        for(int i=0; i<_originFields.size(); i++) {
    +            sizes[i] = _originFields.get(i).size();
    +        }
    +        _factory = new ComboList.Factory(sizes);
    +    }
    +
    +    @Override
    +    public JoinState init(TridentCollector collector, TridentTuple group) {
    +        return new JoinState(_types.size(), group);
    +    }
    +
    +    @Override
    +    public void execute(JoinState state, int streamIndex, TridentTuple group, TridentTuple input, TridentCollector collector) {
    +        //TODO: do the inner join incrementally, emitting the cross join with this tuple, against all other sides
    +        //TODO: only do cross join if at least one tuple in each side
    +        List<List> side = state.sides[streamIndex];
    +        if(side.isEmpty()) {
    +            state.numSidesReceived++;
    +        }
    +
    +        side.add(input);
    +        if(state.numSidesReceived == state.sides.length) {
    +            emitCrossJoin(state, collector, streamIndex, input);
    +        }
    +    }
    +
    +    @Override
    +    public void complete(JoinState state, TridentTuple group, TridentCollector collector) {
    +        List<List>[] sides = state.sides;
    +        boolean wasEmpty = state.numSidesReceived < sides.length;
    +        for(int i=0; i<sides.length; i++) {
    +            if(sides[i].isEmpty() && _types.get(i) == JoinType.OUTER) {
    +                state.numSidesReceived++;
    +                sides[i].add(null);
    +            }
    +        }
    +        if(wasEmpty && state.numSidesReceived == sides.length) {
    +            emitCrossJoin(state, collector, -1, null);
    +        }
    +    }
    +
    +    @Override
    +    public void cleanup() {
    +    }
    +
    +    private List<Object> makeNullList(int size) {
    +        List<Object> ret = new ArrayList(size);
    +        for(int i=0; i<size; i++) {
    +            ret.add(null);
    +        }
    +        return ret;
    +    }
    +
    +    private void emitCrossJoin(JoinState state, TridentCollector collector, int overrideIndex, TridentTuple overrideTuple) {
    +        List<List>[] sides = state.sides;
    +        int[] indices = state.indices;
    +        for(int i=0; i<indices.length; i++) {
    +            indices[i] = 0;
    +        }
    +        
    +        boolean keepGoing = true;
    +        //emit cross-join of all emitted tuples
    +        while(keepGoing) {
    +            List[] combined = new List[sides.length];
    +
    +            for (int i = 0; i < sides.length; i++) {
    +                List<Object> values = buildValuesForStream(state, overrideIndex, overrideTuple, sides, indices, combined, i);
    +                combined[i] = values;
    +            }
    +            collector.emit(_factory.create(combined));
    +            keepGoing = increment(sides, indices, indices.length - 1, overrideIndex);
    +        }
    +    }
    +
    +    private List<Object> buildValuesForStream(JoinState state, int overrideIndex, TridentTuple overrideTuple, List<List>[] sides,
    +                                              int[] indices, List[] combined, int streamIdx) {
    +        List sideValues;
    +        if (streamIdx == overrideIndex) {
    +            sideValues = overrideTuple;
    +        } else {
    +            sideValues = sides[streamIdx].get(indices[streamIdx]);
    +        }
    +
    +        Fields originFields = _originFields.get(streamIdx);
    +        if (sideValues == null) {
    +            return makeNullList(originFields.size());
    +        } else {
    +            List<Object> ret = new ArrayList<>(originFields.size());
    +            Fields sideFields = _sideFields.get(streamIdx);
    +            Fields joinFields = _joiningFields.get(streamIdx);
    +            int sideIdx = 0;
    +            for (String field : originFields) {
    +                // assuming _sideFields are preserving its order
    +                if (sideFields.contains(field)) {
    +                    ret.add(sideValues.get(sideIdx++));
    +                } else {
    +                    // group field
    +                    ret.add(state.group.get(joinFields.fieldIndex(field)));
    +                }
    +            }
    +            return ret;
    +        }
    +    }
    +
    +
    +    //return false if can't increment anymore
    +    //TODO: DRY this code up with what's in ChainedAggregatorImpl
    +    private boolean increment(List[] lengths, int[] indices, int j, int overrideIndex) {
    +        if(j==-1) return false;
    --- End diff --
    
    space after if


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