| /* |
| * Copyright 2009-2010 by The Regents of the University of California |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * you may obtain a copy of the License from |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package edu.uci.ics.asterix.runtime.evaluators.functions; |
| |
| import java.io.DataOutput; |
| import java.io.IOException; |
| |
| import edu.uci.ics.asterix.om.functions.AsterixBuiltinFunctions; |
| import edu.uci.ics.asterix.om.functions.IFunctionDescriptor; |
| import edu.uci.ics.asterix.om.functions.IFunctionDescriptorFactory; |
| import edu.uci.ics.asterix.om.types.ATypeTag; |
| import edu.uci.ics.asterix.runtime.evaluators.base.AbstractScalarFunctionDynamicDescriptor; |
| import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException; |
| import edu.uci.ics.hyracks.algebricks.core.algebra.functions.FunctionIdentifier; |
| import edu.uci.ics.hyracks.algebricks.runtime.base.ICopyEvaluator; |
| import edu.uci.ics.hyracks.algebricks.runtime.base.ICopyEvaluatorFactory; |
| import edu.uci.ics.hyracks.data.std.api.IDataOutputProvider; |
| import edu.uci.ics.hyracks.data.std.util.ArrayBackedValueStorage; |
| import edu.uci.ics.hyracks.dataflow.common.data.accessors.IFrameTupleReference; |
| |
| /** |
| * This runtime function checks if the input is null. |
| * If the input is not null, just return it directly; |
| * Otherwise, throw a runtime exception. |
| */ |
| public class NotNullDescriptor extends AbstractScalarFunctionDynamicDescriptor { |
| |
| private static final long serialVersionUID = 1L; |
| public static final IFunctionDescriptorFactory FACTORY = new IFunctionDescriptorFactory() { |
| public IFunctionDescriptor createFunctionDescriptor() { |
| return new NotNullDescriptor(); |
| } |
| }; |
| private final static byte SER_NULL_TYPE_TAG = ATypeTag.NULL.serialize(); |
| |
| @Override |
| public ICopyEvaluatorFactory createEvaluatorFactory(final ICopyEvaluatorFactory[] args) { |
| return new ICopyEvaluatorFactory() { |
| private static final long serialVersionUID = 1L; |
| |
| @Override |
| public ICopyEvaluator createEvaluator(final IDataOutputProvider output) throws AlgebricksException { |
| return new ICopyEvaluator() { |
| private DataOutput out = output.getDataOutput(); |
| private ArrayBackedValueStorage outInput = new ArrayBackedValueStorage(); |
| private ICopyEvaluator eval = args[0].createEvaluator(outInput); |
| private String errorMessage = AsterixBuiltinFunctions.NOT_NULL |
| + ": the input value cannot be NULL."; |
| |
| @Override |
| public void evaluate(IFrameTupleReference tuple) throws AlgebricksException { |
| |
| try { |
| outInput.reset(); |
| eval.evaluate(tuple); |
| byte[] data = outInput.getByteArray(); |
| if (data[outInput.getStartOffset()] == SER_NULL_TYPE_TAG) { |
| throw new AlgebricksException(errorMessage); |
| } |
| out.write(data, outInput.getStartOffset(), outInput.getLength()); |
| } catch (IOException e1) { |
| throw new AlgebricksException(errorMessage); |
| } |
| } |
| }; |
| } |
| }; |
| } |
| |
| @Override |
| public FunctionIdentifier getIdentifier() { |
| return AsterixBuiltinFunctions.NOT_NULL; |
| } |
| |
| } |