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Kinetica Java API

Overview

There are two projects in this repository: the Kinetica Java API and an example project.

API

In the api directory, run the following command to create the API JAR:

> mvn clean package

In order to use the API JAR for the example, run the following command to install the JAR in the local repository:

> mvn install

The documentation can be found at https://docs.kinetica.com/7.2/. The Java specific documentation can be found at:

For changes to the client-side API, please refer to CHANGELOG.md. For changes to Kinetica functions, please refer to CHANGELOG-FUNCTIONS.md.

KIFS File upload and download facility

The purpose of this API is to facilitate uploading of files into KIFS from a local directory and downloading from the KIFS into a local directory. There are multiple methods available for uploading and downloading files. This new facility is available for Kinetica version 7.1.4.0 onwards.

GPUdbFileHandler API

The upload and the download methods of the class GPUdbFileHandler are overloaded to accommodate either a single file name, or a list of file names to upload to or download from KIFS.

The following methods are available -

  • upload - Has multiple overloads for uploading single/multiple files.
  • download - Has similar overloads as uploads for downloading files.

API Logging

The Java API uses the Simple Logging Facade for Java (SLF4J) with Logback as the default backend for flexibility and convenience. Users of the API are encouraged to use the SLF4J logging interface as well.

{
    // Example of creating and using a SLF4J logger a java class file.
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    ...
    private static Logger LOGGER = LoggerFactory.getLogger(Example.class);
    ...
    LOGGER.warn("..."); // trace(), debug(), info(), warn(), error()
}

The default logging level is INFO and output will be sent to a STDOUT appender. The com.gpudb logging level can be set by a system property when running a JAR with the arg -Dlogging.level.com.gpudb=DEBUG and a convenience function has been added to change the level from Java code.

com.gpudb.GPUdbLogger.setLoggingLevel("DEBUG");

A complete Logback logging configuration can be specified with a logback.xml resource file in the application POM or on the command-line when running the JAR with a -Dlogback.configurationFile=/path/to/logback.xml arg. See the Kinetica API's logback.xml file for an example of a STDOUT logger. The full documentation, including examples, of a Logback configuration file can be found here: https://logback.qos.ch/manual/configuration.html

    <!-- Example resource for logback configuration file in an application pom.xml file. -->
    <resource>
        <directory>src/main/resources</directory>
        <includes>
            <include>logback.xml</include>
        </includes>
    </resource>

The SLF4J logger backend can be changed to any of the supported backends, including log4j, by requiring the appropriate wrapper package and excluding the logback-classic backend. See https://www.slf4j.org/legacy.html for more information. Note that if the SLF4J backend is changed from Logback the convenience function GPUdbLogger.setLoggingLevel() and the system parameter logging.level.com.gpudb will not work to change the log level. The level will have to be set using the new logger implementation.

    <!-- Example of log4j2 as the slf4j backend for the application and GPUdb API in a pom.xml file. -->
    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-api</artifactId>
        <version>2.7</version>
    </dependency>
    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-core</artifactId>
        <version>2.7</version>
    </dependency>
    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-slf4j-impl</artifactId>
        <version>2.7</version>
    </dependency>
    <dependency>
        <groupId>com.gpudb</groupId>
        <artifactId>gpudb-api</artifactId>
        <version>${gpudb-api.version}</version>
        <exclusions>
            <exclusion>
                <groupId>ch.qos.logback</groupId>
                <artifactId>logback-classic</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

    ...

    <resource>
        <directory>src/main/resources</directory>
        <includes>
            <include>log4j2.xml</include>
        </includes>
    </resource>

SSL Configuration

When the Kinetica server is configured to use SSL, the root certificate needs to be installed in the client machine for the API to successfully make secured connections with the server. Please ensure that the root certificate is either installed in the default java key store (JKS), or supply the separate certificate JKS and its password to the API via the following two system environment variables:

  • javax.net.ssl.trustStore
  • javax.net.ssl.trustStorePassword

This can be done by setting the Java Runtime Environment (JRE) variables at the command line by using the following arguments:

  • -Djavax.net.ssl.trustStore
  • -Djavax.net.ssl.trustStorePassword

The environment variables can also be programmatically set from applications that use the Java API:

System.setProperty( "javax.net.ssl.trustStore", trustStorePath );
System.setProperty( "javax.net.ssl.trustStorePassword", trustStorePassword );

Example

To build the JAR, run the following command in the example directory:

> mvn clean package

Then, to run the example, in the target directory, run the following command:

> java -jar gpudb-api-example-1.0-jar-with-dependencies.jar

To provide the URL of the Kinetica server and/or configure the log level, use the following options:

> java -DlogLevel=debug -Durl=http://172.42.0.80:9191 \
     -jar gpudb-api-example-1.0-jar-with-dependencies.jar

Note that the default URL is http://localhost:9191. Also note that the two options, if given, must precede the -jar option.

Please make sure that Kinetica is running at the URL and port specified in line 4 of Example.java (the default is http://localhost:9191).

GPUdbFileHandler Example

An example usage of the API can be found in the gpudb-api-example project in the file GPUdbFileHandlerExample.java. The example can be run using the command -

> java -Durl="http://10.0.0.10:9191" -DlogLevel="INFO" \
-cp ./target/gpudb-api-example-1.0-jar-with-dependencies.jar \
com.gpudb.example.GPUdbFileHandlerExample

The URL VM argument needs to be changed suitably to match the exact environment.

Support

For bugs, please submit an issue on Github.

For support, you can post on stackoverflow under the kinetica tag or Slack.

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