asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/functions/InjectFailureDescriptor.java

package edu.uci.ics.asterix.runtime.evaluators.functions;

import java.io.IOException;

import edu.uci.ics.asterix.dataflow.data.nontagged.serde.ABooleanSerializerDeserializer;
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.om.types.EnumDeserializer;
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;

public class InjectFailureDescriptor extends AbstractScalarFunctionDynamicDescriptor {

    private static final long serialVersionUID = 1L;
    public static final IFunctionDescriptorFactory FACTORY = new IFunctionDescriptorFactory() {
        public IFunctionDescriptor createFunctionDescriptor() {
            return new InjectFailureDescriptor();
        }
    };

    @Override
    public FunctionIdentifier getIdentifier() {
        return AsterixBuiltinFunctions.INJECT_FAILURE;
    }

    @Override
    public ICopyEvaluatorFactory createEvaluatorFactory(final ICopyEvaluatorFactory[] args) throws AlgebricksException {

        return new ICopyEvaluatorFactory() {
            private static final long serialVersionUID = 1L;

            @Override
            public ICopyEvaluator createEvaluator(final IDataOutputProvider output) throws AlgebricksException {

                final ArrayBackedValueStorage argOut = new ArrayBackedValueStorage();
                final ICopyEvaluator[] evals = new ICopyEvaluator[args.length];
                evals[0] = args[0].createEvaluator(argOut);
                evals[1] = args[1].createEvaluator(argOut);

                return new ICopyEvaluator() {

                    @Override
                    public void evaluate(IFrameTupleReference tuple) throws AlgebricksException {
                        try {
                            // evaluator the failure condition
                            argOut.reset();
                            evals[1].evaluate(tuple);
                            ATypeTag typeTag = EnumDeserializer.ATYPETAGDESERIALIZER
                                    .deserialize(argOut.getByteArray()[0]);
                            if (typeTag == ATypeTag.BOOLEAN) {
                                boolean argResult = ABooleanSerializerDeserializer.getBoolean(argOut.getByteArray(), 1);
                                if (argResult)
                                    throw new AlgebricksException(AsterixBuiltinFunctions.INJECT_FAILURE
                                            + ": injecting a intended failure");
                            }

                            // evaluate the real evaluator
                            argOut.reset();
                            evals[0].evaluate(tuple);
                            output.getDataOutput().write(argOut.getByteArray(), argOut.getStartOffset(),
                                    argOut.getLength());
                        } catch (IOException e) {
                            throw new AlgebricksException(e);
                        }
                    }

                };
            }
        };
    }
}