external/storm-hbase/src/main/java/org/apache/storm/hbase/bolt/mapper/HBaseProjectionCriteria.java

/**
 * 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.hbase.bolt.mapper;

import com.google.common.collect.Lists;

import java.io.Serializable;
import java.util.List;

/**
 * Allows the user to specify the projection criteria.
 * If only columnFamily is specified all columns from that family will be returned.
 * If a column is specified only that column from that family will be returned.

 */
public class HBaseProjectionCriteria implements Serializable {
    private List<byte[]> columnFamilies;
    private List<ColumnMetaData> columns;

    public static class ColumnMetaData implements Serializable {
        private byte[]  columnFamily;
        private byte[] qualifier;

        public ColumnMetaData(String columnFamily, String qualifier) {
            this.columnFamily = columnFamily.getBytes();
            this.qualifier = qualifier.getBytes();
        }

        public byte[] getColumnFamily() {
            return columnFamily;
        }

        public byte[] getQualifier() {
            return qualifier;
        }
    }

    public HBaseProjectionCriteria() {
        columnFamilies = Lists.newArrayList();
        columns = Lists.newArrayList();
    }

    /**
     * all columns from this family will be included as result of HBase lookup.
     * @param columnFamily
     * @return
     */
    public HBaseProjectionCriteria addColumnFamily(String columnFamily) {
        this.columnFamilies.add(columnFamily.getBytes());
        return this;
    }

    /**
     * Only this column from the the columnFamily will be included as result of HBase lookup.
     * @param column
     * @return
     */
    public HBaseProjectionCriteria addColumn(ColumnMetaData column) {
        this.columns.add(column);
        return this;
    }

    public List<ColumnMetaData> getColumns() {
        return columns;
    }

    public List<byte[]> getColumnFamilies() {
        return columnFamilies;
    }
}