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/tags/release-0.1-rc2/hive/external/ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDFOPNull.java

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Java | 59 lines | 31 code | 7 blank | 21 comment | 4 complexity | c83f93d198146896fb9738a389d8615b MD5 | raw file
Possible License(s): Apache-2.0, BSD-3-Clause, JSON, CPL-1.0
  1. /**
  2. * Licensed to the Apache Software Foundation (ASF) under one
  3. * or more contributor license agreements. See the NOTICE file
  4. * distributed with this work for additional information
  5. * regarding copyright ownership. The ASF licenses this file
  6. * to you under the Apache License, Version 2.0 (the
  7. * "License"); you may not use this file except in compliance
  8. * with the License. You may obtain a copy of the License at
  9. *
  10. * http://www.apache.org/licenses/LICENSE-2.0
  11. *
  12. * Unless required by applicable law or agreed to in writing, software
  13. * distributed under the License is distributed on an "AS IS" BASIS,
  14. * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15. * See the License for the specific language governing permissions and
  16. * limitations under the License.
  17. */
  18. package org.apache.hadoop.hive.ql.udf.generic;
  19. import org.apache.hadoop.hive.ql.exec.Description;
  20. import org.apache.hadoop.hive.ql.exec.UDFArgumentException;
  21. import org.apache.hadoop.hive.ql.exec.UDFArgumentLengthException;
  22. import org.apache.hadoop.hive.ql.metadata.HiveException;
  23. import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
  24. import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;
  25. import org.apache.hadoop.io.BooleanWritable;
  26. /**
  27. * GenericUDFOPNull.
  28. *
  29. */
  30. @Description(name = "isnull", value = "_FUNC_ a - Returns true if a is NULL and false otherwise")
  31. public class GenericUDFOPNull extends GenericUDF {
  32. private BooleanWritable result = new BooleanWritable();
  33. @Override
  34. public ObjectInspector initialize(ObjectInspector[] arguments)
  35. throws UDFArgumentException {
  36. if (arguments.length != 1) {
  37. throw new UDFArgumentLengthException(
  38. "The operator 'IS NULL' only accepts 1 argument.");
  39. }
  40. return PrimitiveObjectInspectorFactory.writableBooleanObjectInspector;
  41. }
  42. @Override
  43. public Object evaluate(DeferredObject[] arguments) throws HiveException {
  44. result.set(arguments[0].get() == null);
  45. return result;
  46. }
  47. @Override
  48. public String getDisplayString(String[] children) {
  49. assert (children.length == 1);
  50. return children[0] + " is null";
  51. }
  52. }