/**
* Takes the actual arguments and returns the result. Gets passed the input, does whatever it
* wants to it, and then returns the output.
*
* <p>The input is accessed using the ObjectInspectors that were saved into global variables in
* the call to initialize()
*
* <p>This method is called once for every row of data being processed. UDFs are called during the
* map phase of the MapReduce job. This means that we have no control over the order in which the
* records get sent to the UDF.
*
* @param arguments
* @return
* @throws HiveException
*/
@Override
public Object evaluate(DeferredObject[] arguments) throws HiveException {
assert arguments != null
: "Method 'evaluate' of HostNormalizerUDF " + "called with null arguments array";
assert arguments.length == 1
: "Method 'evaluate' of "
+ "HostNormalizerUDF called arguments of length "
+ arguments.length
+ " (instead of 1)";
// arguments is an array with exactly 1 entry.
assert result != null : "Result object has not yet been initialized, " + "but evaluate called";
// result object has been initialized. So it's an array of objects of
// the right length.
String uriHost = argumentOI.getPrimitiveJavaObject(arguments[0].get());
NormalizedHostInfo normHost = webrequest.normalizeHost(uriHost);
if (normHost == null) {
result[IDX_PROJECT_CLASS] = NormalizedHostInfo.EMPTY_NORM_HOST_VALUE;
result[IDX_PROJECT] = NormalizedHostInfo.EMPTY_NORM_HOST_VALUE;
result[IDX_QUALIFIERS] = new ArrayList<String>();
result[IDX_TLD] = NormalizedHostInfo.EMPTY_NORM_HOST_VALUE;
} else {
result[IDX_PROJECT_CLASS] = normHost.getProjectClass();
result[IDX_PROJECT] = normHost.getProject();
result[IDX_QUALIFIERS] = normHost.getQualifiers();
result[IDX_TLD] = normHost.getTld();
}
return result;
}
/**
* The initialize method is called only once during the lifetime of the UDF.
*
* <p>Method checks for the validity (number, type, etc) of the arguments being passed to the UDF.
* It also sets the return type of the result of the UDF, in this case the ObjectInspector
* equivalent of Map<String,Object>
*
* @param arguments
* @return ObjectInspector Map<String,Object>
* @throws UDFArgumentException
*/
@Override
public ObjectInspector initialize(ObjectInspector[] arguments) throws UDFArgumentException {
if (arguments.length != 1) {
throw new UDFArgumentLengthException(
"The HostNormalizerUDF takes an array with only 1 element as argument");
}
// we are expecting the parameter to be of String type.
ObjectInspector arg = arguments[0];
int argIndex = 0;
if (arg.getCategory() != Category.PRIMITIVE) {
throw new UDFArgumentTypeException(
argIndex,
"A string argument was expected but an argument of type "
+ arg.getTypeName()
+ " was given.");
}
// Now that we have made sure that the argument is of primitive type, we can get the primitive
// category
PrimitiveCategory primitiveCategory = ((PrimitiveObjectInspector) arg).getPrimitiveCategory();
if (primitiveCategory != PrimitiveCategory.STRING) {
throw new UDFArgumentTypeException(
argIndex,
"A string argument was expected but an argument of type "
+ arg.getTypeName()
+ " was given.");
}
// Instantiate the Webrequest
webrequest = Webrequest.getInstance();
argumentOI = (StringObjectInspector) arg;
List<String> fieldNames = new LinkedList<>();
List<ObjectInspector> fieldOIs = new LinkedList<>();
int idx = 0;
fieldNames.add("project_class");
fieldOIs.add(PrimitiveObjectInspectorFactory.javaStringObjectInspector);
IDX_PROJECT_CLASS = idx++;
fieldNames.add("project");
fieldOIs.add(PrimitiveObjectInspectorFactory.javaStringObjectInspector);
IDX_PROJECT = idx++;
fieldNames.add("qualifiers");
fieldOIs.add(
ObjectInspectorFactory.getStandardListObjectInspector(
PrimitiveObjectInspectorFactory.javaStringObjectInspector));
IDX_QUALIFIERS = idx++;
fieldNames.add("tld");
fieldOIs.add(PrimitiveObjectInspectorFactory.javaStringObjectInspector);
IDX_TLD = idx++;
result = new Object[idx];
return ObjectInspectorFactory.getStandardStructObjectInspector(fieldNames, fieldOIs);
}
