vxquery-core/src/main/java/org/apache/vxquery/runtime/functions/json/JnDocScalarEvaluatorFactory.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 at
 *
 *     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 org.apache.vxquery.runtime.functions.json;

import java.io.DataInputStream;
import java.io.IOException;

import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluator;
import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluatorFactory;
import org.apache.hyracks.api.context.IHyracksTaskContext;
import org.apache.hyracks.api.exceptions.HyracksDataException;
import org.apache.hyracks.data.std.api.IPointable;
import org.apache.hyracks.data.std.primitive.UTF8StringPointable;
import org.apache.hyracks.data.std.util.ArrayBackedValueStorage;
import org.apache.hyracks.dataflow.common.comm.util.ByteBufferInputStream;
import org.apache.vxquery.datamodel.accessors.TaggedValuePointable;
import org.apache.vxquery.datamodel.values.ValueTag;
import org.apache.vxquery.exceptions.ErrorCode;
import org.apache.vxquery.exceptions.SystemException;
import org.apache.vxquery.jsonparser.JSONParser;
import org.apache.vxquery.runtime.functions.base.AbstractTaggedValueArgumentScalarEvaluator;
import org.apache.vxquery.runtime.functions.base.AbstractTaggedValueArgumentScalarEvaluatorFactory;
import org.apache.vxquery.runtime.functions.util.FunctionHelper;
import org.apache.vxquery.xmlparser.IParser;

public class JnDocScalarEvaluatorFactory extends AbstractTaggedValueArgumentScalarEvaluatorFactory {

    private static final long serialVersionUID = 1L;

    public JnDocScalarEvaluatorFactory(IScalarEvaluatorFactory[] args) {
        super(args);
    }

    @Override
    protected IScalarEvaluator createEvaluator(IHyracksTaskContext ctx, IScalarEvaluator[] args)
            throws HyracksDataException {
        final UTF8StringPointable stringp = (UTF8StringPointable) UTF8StringPointable.FACTORY.createPointable();
        final ArrayBackedValueStorage abvs = new ArrayBackedValueStorage();
        final ByteBufferInputStream bbis = new ByteBufferInputStream();
        final DataInputStream di = new DataInputStream(bbis);

        return new AbstractTaggedValueArgumentScalarEvaluator(args) {

            @Override
            protected void evaluate(TaggedValuePointable[] args, IPointable result) throws SystemException {
                TaggedValuePointable tvp = args[0];
                if (tvp.getTag() != ValueTag.XS_STRING_TAG) {
                    throw new SystemException(ErrorCode.FORG0006);
                }
                tvp.getValue(stringp);
                try {
                    IParser parser = new JSONParser();
                    FunctionHelper.readInDocFromPointable(stringp, bbis, di, abvs, parser);
                } catch (IOException e) {
                    throw new SystemException(ErrorCode.FODC0002, e);
                }
                result.set(abvs);
            }

        };
    }

}