hyracks-storage-am-btree/src/main/java/edu/uci/ics/hyracks/storage/am/btree/dataflow/BTreeSearchOperatorNodePushable.java

/*
 * Copyright 2009-2010 by The Regents of the University of California
 * 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 from
 * 
 *     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 edu.uci.ics.hyracks.storage.am.btree.dataflow;

import java.io.DataOutput;
import java.nio.ByteBuffer;

import edu.uci.ics.hyracks.api.context.IHyracksStageletContext;
import edu.uci.ics.hyracks.api.dataflow.value.IBinaryComparator;
import edu.uci.ics.hyracks.api.dataflow.value.IRecordDescriptorProvider;
import edu.uci.ics.hyracks.api.dataflow.value.RecordDescriptor;
import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
import edu.uci.ics.hyracks.dataflow.common.comm.io.ArrayTupleBuilder;
import edu.uci.ics.hyracks.dataflow.common.comm.io.FrameTupleAccessor;
import edu.uci.ics.hyracks.dataflow.common.comm.io.FrameTupleAppender;
import edu.uci.ics.hyracks.dataflow.common.comm.util.FrameUtils;
import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
import edu.uci.ics.hyracks.dataflow.std.base.AbstractUnaryInputUnaryOutputOperatorNodePushable;
import edu.uci.ics.hyracks.storage.am.btree.api.IBTreeCursor;
import edu.uci.ics.hyracks.storage.am.btree.api.IBTreeLeafFrame;
import edu.uci.ics.hyracks.storage.am.btree.impls.BTree;
import edu.uci.ics.hyracks.storage.am.btree.impls.BTreeOp;
import edu.uci.ics.hyracks.storage.am.btree.impls.BTreeOpContext;
import edu.uci.ics.hyracks.storage.am.btree.impls.MultiComparator;
import edu.uci.ics.hyracks.storage.am.btree.impls.RangePredicate;
import edu.uci.ics.hyracks.storage.am.btree.impls.RangeSearchCursor;

public class BTreeSearchOperatorNodePushable extends AbstractUnaryInputUnaryOutputOperatorNodePushable {
    private BTreeOpHelper btreeOpHelper;
    private FrameTupleAccessor accessor;

    private ByteBuffer writeBuffer;
    private FrameTupleAppender appender;
    private ArrayTupleBuilder tb;
    private DataOutput dos;

    private BTree btree;
    private boolean isForward;
    private PermutingFrameTupleReference lowKey;
    private PermutingFrameTupleReference highKey;
    private boolean lowKeyInclusive;
    private boolean highKeyInclusive;
    private RangePredicate rangePred;
    private MultiComparator lowKeySearchCmp;
    private MultiComparator highKeySearchCmp;
    private IBTreeCursor cursor;
    private IBTreeLeafFrame cursorFrame;
    private BTreeOpContext opCtx;

    private RecordDescriptor recDesc;

    public BTreeSearchOperatorNodePushable(AbstractBTreeOperatorDescriptor opDesc, IHyracksStageletContext ctx,
            int partition, IRecordDescriptorProvider recordDescProvider, boolean isForward, int[] lowKeyFields,
            int[] highKeyFields, boolean lowKeyInclusive, boolean highKeyInclusive) {
        btreeOpHelper = new BTreeOpHelper(opDesc, ctx, partition, BTreeOpHelper.BTreeMode.OPEN_BTREE);
        this.isForward = isForward;
        this.lowKeyInclusive = lowKeyInclusive;
        this.highKeyInclusive = highKeyInclusive;
        this.recDesc = recordDescProvider.getInputRecordDescriptor(opDesc.getOperatorId(), 0);
        if (lowKeyFields != null && lowKeyFields.length > 0) {
            lowKey = new PermutingFrameTupleReference();
            lowKey.setFieldPermutation(lowKeyFields);
        }
        if (highKeyFields != null && highKeyFields.length > 0) {
            highKey = new PermutingFrameTupleReference();
            highKey.setFieldPermutation(highKeyFields);
        }
    }

    @Override
    public void open() throws HyracksDataException {
        AbstractBTreeOperatorDescriptor opDesc = btreeOpHelper.getOperatorDescriptor();
        accessor = new FrameTupleAccessor(btreeOpHelper.getHyracksStageletContext().getFrameSize(), recDesc);

        cursorFrame = opDesc.getLeafFactory().getFrame();
        cursor = new RangeSearchCursor(cursorFrame);

        btreeOpHelper.init();
        btree = btreeOpHelper.getBTree();

        // construct range predicate

        int lowKeySearchFields = btree.getMultiComparator().getComparators().length;
        int highKeySearchFields = btree.getMultiComparator().getComparators().length;
        if (lowKey != null)
            lowKeySearchFields = lowKey.getFieldCount();
        if (highKey != null)
            highKeySearchFields = highKey.getFieldCount();

        IBinaryComparator[] lowKeySearchComparators = new IBinaryComparator[lowKeySearchFields];
        for (int i = 0; i < lowKeySearchFields; i++) {
            lowKeySearchComparators[i] = btree.getMultiComparator().getComparators()[i];
        }
        lowKeySearchCmp = new MultiComparator(btree.getMultiComparator().getTypeTraits(), lowKeySearchComparators);

        if (lowKeySearchFields == highKeySearchFields) {
            highKeySearchCmp = lowKeySearchCmp;
        } else {
            IBinaryComparator[] highKeySearchComparators = new IBinaryComparator[highKeySearchFields];
            for (int i = 0; i < highKeySearchFields; i++) {
                highKeySearchComparators[i] = btree.getMultiComparator().getComparators()[i];
            }
            highKeySearchCmp = new MultiComparator(btree.getMultiComparator().getTypeTraits(), highKeySearchComparators);

        }

        rangePred = new RangePredicate(isForward, null, null, lowKeyInclusive, highKeyInclusive, lowKeySearchCmp,
                highKeySearchCmp);

        accessor = new FrameTupleAccessor(btreeOpHelper.getHyracksStageletContext().getFrameSize(), recDesc);

        writeBuffer = btreeOpHelper.getHyracksStageletContext().allocateFrame();
        tb = new ArrayTupleBuilder(btree.getMultiComparator().getFieldCount());
        dos = tb.getDataOutput();
        appender = new FrameTupleAppender(btreeOpHelper.getHyracksStageletContext().getFrameSize());
        appender.reset(writeBuffer, true);

        opCtx = btree.createOpContext(BTreeOp.BTO_SEARCH, btreeOpHelper.getLeafFrame(),
                btreeOpHelper.getInteriorFrame(), null);
    }

    private void writeSearchResults() throws Exception {
        while (cursor.hasNext()) {
            tb.reset();
            cursor.next();

            ITupleReference frameTuple = cursor.getTuple();
            for (int i = 0; i < frameTuple.getFieldCount(); i++) {
                dos.write(frameTuple.getFieldData(i), frameTuple.getFieldStart(i), frameTuple.getFieldLength(i));
                tb.addFieldEndOffset();
            }

            if (!appender.append(tb.getFieldEndOffsets(), tb.getByteArray(), 0, tb.getSize())) {
                FrameUtils.flushFrame(writeBuffer, writer);
                appender.reset(writeBuffer, true);
                if (!appender.append(tb.getFieldEndOffsets(), tb.getByteArray(), 0, tb.getSize())) {
                    throw new IllegalStateException();
                }
            }
        }
    }

    @Override
    public void nextFrame(ByteBuffer buffer) throws HyracksDataException {
        accessor.reset(buffer);

        int tupleCount = accessor.getTupleCount();
        try {
            for (int i = 0; i < tupleCount; i++) {
                if (lowKey != null)
                    lowKey.reset(accessor, i);
                if (highKey != null)
                    highKey.reset(accessor, i);
                rangePred.setLowKey(lowKey, lowKeyInclusive);
                rangePred.setHighKey(highKey, highKeyInclusive);

                cursor.reset();
                btree.search(cursor, rangePred, opCtx);
                writeSearchResults();
            }
        } catch (Exception e) {
            throw new HyracksDataException(e);
        }
    }

    @Override
    public void close() throws HyracksDataException {
        try {
            if (appender.getTupleCount() > 0) {
                FrameUtils.flushFrame(writeBuffer, writer);
            }
            writer.close();
            try {
                cursor.close();
            } catch (Exception e) {
                throw new HyracksDataException(e);
            }
        } finally {
            btreeOpHelper.deinit();
        }
    }

    @Override
    public void flush() throws HyracksDataException {
        if (appender.getTupleCount() > 0) {
            FrameUtils.flushFrame(writeBuffer, writer);
        }
    }
}