THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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The PDK is planned for inclusion in the Hive 0.8.0 release; until that is available, please download a recent snapshot build from Jenkins; make sure it includes HIVE-2244.
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To demonstrate the PDK in action, the Hive release includes an examples/test-plugin directory. You can build the test plugin by changing to that directory and running
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ant -Dhive.install.dir=../..
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You can run the tests associated with the plugin via
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ant -Dhive.install.dir=../.. test
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If all is well, you should see output like
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Buildfile: /hive-0.8.0-SNAPSHOT/examples/test-plugin/build.xml
get-class-list:
test:
[junit] Running org.apache.hive.pdk.PluginTest
[junit] Tests run: 2, Failures: 0, Errors: 0, Time elapsed: 38.955 sec
BUILD SUCCESSFUL
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To create your own plugin, you can follow the patterns from the example plugin. Let's take a closer look at it. First, the build.xml:
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<project name="pdktest" default="package">
<property name="plugin.libname" value="pdk-test-udf"/>
<property name="plugin.title" value="Hive PDK Test UDF Library"/>
<property name="plugin.version" value="0.1"/>
<property name="plugin.vendor" value="Apache Software Foundation"/>
<property name="function.sql.prefix" value="tp_"/>
<import file="${hive.install.dir}/scripts/pdk/build-plugin.xml"/>
</project>
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Now let's take a look at the source code for a UDF.
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package org.apache.hive.pdktest;
import org.apache.hive.pdk.HivePdkUnitTest;
import org.apache.hive.pdk.HivePdkUnitTests;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDF;
import org.apache.hadoop.io.Text;
/**
* Example UDF for rot13 transformation.
*/
@Description(name = "rot13",
value = "_FUNC_(str) - Returns str with all characters transposed via rot13",
extended = "Example:\n"
+ " > SELECT _FUNC_('Facebook') FROM src LIMIT 1;\n" + " 'Snprobbx'")
@HivePdkUnitTests(
setup = "create table rot13_data(s string); "
+ "insert overwrite table rot13_data select 'Facebook' from onerow;",
cleanup = "drop table if exists rot13_data;",
cases = {
@HivePdkUnitTest(
query = "SELECT tp_rot13('Mixed Up!') FROM onerow;",
result = "Zvkrq Hc!"),
@HivePdkUnitTest(
query = "SELECT tp_rot13(s) FROM rot13_data;",
result = "Snprobbx")
}
)
public class Rot13 extends UDF {
private Text t = new Text();
public Rot13() {
}
public Text evaluate(Text s) {
StringBuilder out = new StringBuilder(s.getLength());
char[] ca = s.toString().toCharArray();
for (char c : ca) {
if (c >= 'a' && c <= 'm') {
c += 13;
} else if (c >= 'n' && c <= 'z') {
c -= 13;
} else if (c >= 'A' && c <= 'M') {
c += 13;
} else if (c >= 'N' && c <= 'Z') {
c -= 13;
}
out.append(c);
}
t.set(out.toString());
return t;
}
}
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