com.google.cloud.bigtable.dataflowimport.DataCellPredicateFactory.java Source code

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Here is the source code for com.google.cloud.bigtable.dataflowimport.DataCellPredicateFactory.java

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/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 *
 * 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 com.google.cloud.bigtable.dataflowimport;

import static com.google.common.base.Preconditions.checkArgument;

import com.google.common.base.Function;
import com.google.common.base.Predicate;
import com.google.common.base.Predicates;

import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.CellComparator;
import org.apache.hadoop.hbase.CellUtil;
import org.apache.hadoop.hbase.KeyValue;

/**
 * Function that creates a {@link com.google.common.base.Predicate}s from a Delete Marker {@code Cell}. The
 * {@code Predicate} returns {@code true} for all cells that should be deleted because of this
 * Delete Marker.
 *
 * <p>A predicate assumes that all cells to be filtered belong to the same row and column family
 * as the seed Delete Marker, and does NOT validate this assumption on cells encountered.
 *
 * @author sduskis
 * @version $Id: $Id
 */
public class DataCellPredicateFactory implements Function<Cell, Predicate<Cell>> {

    /** {@inheritDoc} */
    @Override
    public Predicate<Cell> apply(Cell deleteMarker) {
        checkArgument(CellUtil.isDelete(deleteMarker), "expecting delete marker cell.");
        switch (KeyValue.Type.codeToType(deleteMarker.getTypeByte())) {
        case Delete:
            // Delete specific column by exact timestamp.
            return Predicates.and(new MatchQualifier(deleteMarker), new MatchExactTimestamp(deleteMarker));
        case DeleteFamilyVersion:
            // Delete all column in family by exact timestamp.
            return new MatchExactTimestamp(deleteMarker);
        case DeleteColumn:
            // Delete specific column up to a timestamp
            return Predicates.and(new MatchQualifier(deleteMarker),
                    new MatchTimestampRangeByUpperBound(deleteMarker));
        case DeleteFamily:
            // Delete all columns in a family up to a timestamp
            return new MatchTimestampRangeByUpperBound(deleteMarker);
        default:
            throw new IllegalStateException("Unexpected type byte: " + deleteMarker.getTypeByte());
        }
    }

    private static class MatchQualifier implements Predicate<Cell> {
        private final Cell deleteMarker;

        MatchQualifier(Cell deleteMarker) {
            this.deleteMarker = deleteMarker;
        }

        @Override
        public boolean apply(Cell cell) {
            return CellComparator.compareQualifiers(deleteMarker, cell) == 0;
        }
    }

    private static class MatchExactTimestamp implements Predicate<Cell> {
        private final Cell deleteMarker;

        MatchExactTimestamp(Cell deleteMarker) {
            this.deleteMarker = deleteMarker;
        }

        @Override
        public boolean apply(Cell cell) {
            return CellComparator.compareTimestamps(deleteMarker, cell) == 0;
        }
    }

    private static class MatchTimestampRangeByUpperBound implements Predicate<Cell> {
        private final Cell deleteMarker;

        MatchTimestampRangeByUpperBound(Cell deleteMarker) {
            this.deleteMarker = deleteMarker;
        }

        @Override
        public boolean apply(Cell cell) {
            // Returns true if deleteMarker.ts >= cell.ts. i.e. the cell should be deleted.
            // CellComparator orders timestamps high to low so '<= 0' is need here.
            return CellComparator.compareTimestamps(deleteMarker, cell) <= 0;
        }
    }
}