hyracks/hyracks-storage-am-lsm-btree/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/btree/impls/LSMBTreeSearchCursor.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.lsm.btree.impls;

import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
import edu.uci.ics.hyracks.dataflow.common.data.accessors.ITupleReference;
import edu.uci.ics.hyracks.storage.am.btree.impls.RangePredicate;
import edu.uci.ics.hyracks.storage.am.common.api.ICursorInitialState;
import edu.uci.ics.hyracks.storage.am.common.api.ISearchPredicate;
import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexCursor;
import edu.uci.ics.hyracks.storage.am.common.api.IndexException;
import edu.uci.ics.hyracks.storage.am.lsm.common.api.ILSMIndexOperationContext;
import edu.uci.ics.hyracks.storage.common.buffercache.IBufferCache;
import edu.uci.ics.hyracks.storage.common.buffercache.ICachedPage;

public class LSMBTreeSearchCursor implements ITreeIndexCursor {

    public enum LSMBTreeSearchType {
        POINT,
        RANGE
    }

    private final LSMBTreePointSearchCursor pointCursor;
    private final LSMBTreeRangeSearchCursor rangeCursor;
    private ITreeIndexCursor currentCursor;

    public LSMBTreeSearchCursor(ILSMIndexOperationContext opCtx) {
        pointCursor = new LSMBTreePointSearchCursor(opCtx);
        rangeCursor = new LSMBTreeRangeSearchCursor(opCtx);
    }

    @Override
    public void open(ICursorInitialState initialState, ISearchPredicate searchPred) throws IndexException,
            HyracksDataException {

        LSMBTreeCursorInitialState lsmInitialState = (LSMBTreeCursorInitialState) initialState;

        LSMBTreeSearchType searchType = LSMBTreeSearchType.RANGE;
        RangePredicate btreePred = (RangePredicate) searchPred;
        if (btreePred.getLowKey() != null && btreePred.getHighKey() != null) {
            if (btreePred.isLowKeyInclusive() && btreePred.isHighKeyInclusive()) {
                if (btreePred.getLowKeyComparator().getKeyFieldCount() == btreePred.getHighKeyComparator()
                        .getKeyFieldCount()) {
                    if (btreePred.getLowKeyComparator().getKeyFieldCount() == lsmInitialState
                            .getOriginalKeyComparator().getKeyFieldCount()) {
                        if (lsmInitialState.getOriginalKeyComparator().compare(btreePred.getLowKey(),
                                btreePred.getHighKey()) == 0) {
                            searchType = LSMBTreeSearchType.POINT;
                        }
                    }
                }
            }
        }
        switch (searchType) {
            case POINT:
                currentCursor = pointCursor;
                break;
            case RANGE:
                currentCursor = rangeCursor;
                break;
            default:
                throw new HyracksDataException("Wrong search type");
        }
        currentCursor.open(lsmInitialState, searchPred);
    }

    @Override
    public boolean hasNext() throws HyracksDataException, IndexException {
        return currentCursor.hasNext();
    }

    @Override
    public void next() throws HyracksDataException {
        currentCursor.next();
    }

    @Override
    public void close() throws HyracksDataException {
        if (currentCursor != null) {
            currentCursor.close();
        }
        currentCursor = null;
    }

    @Override
    public void reset() throws HyracksDataException, IndexException {
        if (currentCursor != null) {
            currentCursor.reset();
        }
        currentCursor = null;
    }

    @Override
    public ITupleReference getTuple() {
        return currentCursor.getTuple();
    }

    @Override
    public ICachedPage getPage() {
        return currentCursor.getPage();
    }

    @Override
    public void setBufferCache(IBufferCache bufferCache) {
        currentCursor.setBufferCache(bufferCache);
    }

    @Override
    public void setFileId(int fileId) {
        currentCursor.setFileId(fileId);

    }

    @Override
    public boolean exclusiveLatchNodes() {
        return currentCursor.exclusiveLatchNodes();
    }

}