net.hydromatic.optiq.impl.csv.JsonEnumerator.java Source code

Introduction

Here is the source code for net.hydromatic.optiq.impl.csv.JsonEnumerator.java

Source

/*
// Licensed to Julian Hyde under one or more contributor license
// agreements. See the NOTICE file distributed with this work for
// additional information regarding copyright ownership.
//
// Julian Hyde 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 net.hydromatic.optiq.impl.csv;

import net.hydromatic.linq4j.Enumerator;
import net.hydromatic.linq4j.Linq4j;

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.*;
import java.util.List;

/** Enumerator that reads from a JSON file. */
class JsonEnumerator implements Enumerator<Object> {
    private final Enumerator<Object> enumerator;

    public JsonEnumerator(File file) {
        try {
            final ObjectMapper mapper = new ObjectMapper();
            mapper.configure(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES, true);
            mapper.configure(JsonParser.Feature.ALLOW_SINGLE_QUOTES, true);
            mapper.configure(JsonParser.Feature.ALLOW_COMMENTS, true);
            //noinspection unchecked
            List<Object> list = mapper.readValue(file, List.class);
            enumerator = Linq4j.enumerator(list);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public Object current() {
        return enumerator.current();
    }

    public boolean moveNext() {
        return enumerator.moveNext();
    }

    public void reset() {
        enumerator.reset();
    }

    public void close() {
        try {
            enumerator.close();
        } catch (Exception e) {
            throw new RuntimeException("Error closing JSON reader", e);
        }
    }
}

// End JsonEnumerator.java