co.cask.cdap.api.dataset.table.Increment.java Source code

Introduction

Here is the source code for co.cask.cdap.api.dataset.table.Increment.java

Source

/*
 * Copyright  2014 Cask Data, Inc.
 *
 * 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 co.cask.cdap.api.dataset.table;

import co.cask.cdap.api.common.Bytes;
import com.google.common.collect.Maps;

import java.util.Map;

/**
 * An Increment interprets the values of columns as 8-byte integers and
 * increments them by the specified value.
 * <ul>
 *   <li>
 *     The operation fails if a column's existing value is
 *     not exactly 8 bytes long (with {@link NumberFormatException}).
 *   </li><li>
 *     If a column to increment does not exist prior to the operation, then the column is created and 
 *     the column's value is set to the increment value.
 *   </li><li>
 *     An increment operation should at least change the value of one column.
 *   </li>
 * </ul>
 */
public class Increment {
    /** 
     * Row to change. 
     */
    private final byte[] row;
    /** 
     * Map of columns/values to increment each column's values by.
     */
    private final Map<byte[], Long> values;

    /**
     * @return Row to change.
     */
    public byte[] getRow() {
        return row;
    }

    /**
     * @return Map of columns/values to increment each column's values by.
     */
    public Map<byte[], Long> getValues() {
        return values;
    }

    // key as byte[]

    /**
     * Changes the values of columns in a row.
     * @param row Row to change.
     */
    public Increment(byte[] row) {
        this.row = row;
        this.values = Maps.newTreeMap(Bytes.BYTES_COMPARATOR);
    }

    /**
     * Changes the value of at least one column in a row.
     * @param row Row to change.
     * @param column Column to change.
     * @param value Value to increment by.
     */
    public Increment(byte[] row, byte[] column, long value) {
        this(row);
        add(column, value);
    }

    /**
     * Adds a column and sets the column's value.
     * @param column Column to add.
     * @param value Column value.
     * @return Instance of this {@link co.cask.cdap.api.dataset.table.Increment}.
     */
    public Increment add(byte[] column, long value) {
        values.put(column, value);
        return this;
    }

    // key & column as String

    /**
     * Changes the values of all of the columns in a row.
     * @param row Row in which all column values are incremented.
     */
    public Increment(String row) {
        this(Bytes.toBytes(row));
    }

    /**
     * Changes the value of at least one column in a row.
     * @param row Row to change.
     * @param column Column to change.
     * @param value Value to increment the column value by.
     */
    public Increment(String row, String column, long value) {
        this(Bytes.toBytes(row));
        add(column, value);
    }

    /**
     * Adds a column and sets the column's value.
     * @param column Column to add.
     * @param value Column value.
     * @return Instance of this {@link co.cask.cdap.api.dataset.table.Increment}.
     */
    public Increment add(String column, long value) {
        return add(Bytes.toBytes(column), value);
    }
}