5.1.15 TimeSeries Container Modification

Overview

This chapter describes the changing the schema of a TimeSeries container. Changing the index is same as changing the index as with a collection, please refer the Collection Modification chapter for details on that process.

Schema Modification

Like you can with Collections, you can add or remove columns after creating a TimeSeriescontainer. Create a new class with the modified columns. The following AnotherInstrumentLog class shows an example of sch a change.

List.1 Modified class (AnotherInstrumentLog.java)

package sample.row;

import java.sql.Blob;
import java.util.Date;

import com.toshiba.mwcloud.gs.RowKey;

public class AnotherInstrumentLog {
/ **
* Timestamp of log
* /
@RowKey
public Date timestamp;

/ **
* ID of WeatherStation
* /
public String weatherStationId;

/ **
* Temperature of the measurement result
* /
public float temperture;

/ **
* Image data obtained by photographing the sky
* /
public Blob liveImage;

/ **
* Added field to InstrumentLog
* /
public String description;
}

• L.33: The new field added to the InstrumentLog class.

While normally GridStore.putTimeSeries (String, Class) would be used but with the modified schema, we need to change the pparameters and use GridStore.putTimeSeries (String, Class, TimeSeriesProperties, boolean) method.

List.2 putTimeSeries Parameters

≪ R > TimeSeries < R > putTimeSeries (java.lang.String name,
                              java.lang.Class < R > rowType,
                              TimeSeriesProperties props,
                              boolean modifiable)
                              throws GSException

The descriptions of each parameter are the same as when used with collections, please refer to the modifying collections chapter for more details.

List 3.Creating a TimeSeries Container with the new Column (TimeSeriesModify.java)

// Modify another schema TimeSeries Container
TimeSeriesProperties timeProp=new TimeSeriesProperties ();
TimeSeries < AnotherInstrumentLog > anotherTs=store.putTimeSeries("weather_station_1",
    AnotherInstrumentLog.class, timeProp,  true );

• L.37: In order to use the putTimeSeries (String, Class, TimeSeriesProperties, boolean) method with the new class, you have to create a new instance of TimeSeriesProperties. See the meta-information section for more information about TimeSeriesProperties.
• L.39: Specify true for the modifiable parameter.

Complete source code

Complete source code used in this sample can be downloaded from the following.

Download: timeseries-modify.zip