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

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

import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.DataOutput;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import edu.uci.ics.asterix.common.utils.UTF8CharSequence;
import edu.uci.ics.asterix.formats.nontagged.AqlBinaryComparatorFactoryProvider;
import edu.uci.ics.asterix.formats.nontagged.AqlSerializerDeserializerProvider;
import edu.uci.ics.asterix.om.base.AString;
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.BuiltinType;
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.api.dataflow.value.IBinaryComparator;
import edu.uci.ics.hyracks.api.dataflow.value.ISerializerDeserializer;
import edu.uci.ics.hyracks.api.exceptions.HyracksDataException;
import edu.uci.ics.hyracks.data.std.api.IDataOutputProvider;
import edu.uci.ics.hyracks.data.std.util.ArrayBackedValueStorage;
import edu.uci.ics.hyracks.data.std.util.ByteArrayAccessibleOutputStream;

/**
 * @author Xiaoyu Ma
 */
public class StringMatchesDescriptor extends AbstractScalarFunctionDynamicDescriptor {
    private static final long serialVersionUID = 1L;

    public static final IFunctionDescriptorFactory FACTORY = new IFunctionDescriptorFactory() {
        public IFunctionDescriptor createFunctionDescriptor() {
            return new StringMatchesDescriptor();
        }
    };

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

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

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

                DataOutput dout = output.getDataOutput();

                return new AbstractBinaryStringBoolEval(dout, args[0], args[1]) {

                    private Pattern pattern = null;
                    private Matcher matcher = null;
                    private ByteArrayAccessibleOutputStream lastPattern = new ByteArrayAccessibleOutputStream();
                    private IBinaryComparator strComp = AqlBinaryComparatorFactoryProvider.INSTANCE
                            .getBinaryComparatorFactory(BuiltinType.ASTRING, true).createBinaryComparator();
                    private UTF8CharSequence carSeq = new UTF8CharSequence();

                    @SuppressWarnings("unchecked")
                    private ISerializerDeserializer<AString> stringSerde = AqlSerializerDeserializerProvider.INSTANCE
                            .getSerializerDeserializer(BuiltinType.ASTRING);

                    @Override
                    protected boolean compute(byte[] lBytes, int lLen, int lStart, byte[] rBytes, int rLen, int rStart,
                            ArrayBackedValueStorage array0, ArrayBackedValueStorage array1) throws AlgebricksException {
                        try {
                            boolean newPattern = false;
                            if (pattern == null) {
                                newPattern = true;
                            } else {
                                int c = strComp.compare(rBytes, rStart, rLen, lastPattern.getByteArray(), 0,
                                        lastPattern.size());
                                if (c != 0) {
                                    newPattern = true;
                                }
                            }
                            if (newPattern) {
                                lastPattern.reset();
                                lastPattern.write(rBytes, rStart, rLen);
                                // ! object creation !
                                DataInputStream di = new DataInputStream(new ByteArrayInputStream(
                                        lastPattern.getByteArray()));
                                AString strPattern = (AString) stringSerde.deserialize(di);
                                // pattern = Pattern.compile(toRegex(strPattern));
                                pattern = Pattern.compile(strPattern.getStringValue());
                            }

                            carSeq.reset(array0, 1);
                            if (newPattern) {
                                matcher = pattern.matcher(carSeq);
                            } else {
                                matcher.reset(carSeq);
                            }
                            return matcher.find();
                        } catch (HyracksDataException e) {
                            throw new AlgebricksException(e);
                        }
                    }

                };
            }
        };
    }

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