JacksonHelper.java example

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/**
 * 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.drill.exec.schema.json.jackson;

import java.io.IOException;

import org.apache.drill.common.types.TypeProtos.MajorType;
import org.apache.drill.common.types.TypeProtos.MinorType;
import org.apache.drill.common.types.Types;

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonToken;

public class JacksonHelper {

  public static final MajorType STRING_TYPE = Types.optional(MinorType.VARCHAR);
  public static final MajorType REPEATED_STRING_TYPE = Types.repeated(MinorType.VARCHAR);
  public static final MajorType BOOLEAN_TYPE = Types.optional(MinorType.BIT);
  public static final MajorType REPEATED_BOOLEAN_TYPE = Types.repeated(MinorType.BIT);
  public static final MajorType ARRAY_TYPE = Types.repeated(MinorType.LATE);
  public static final MajorType MAP_TYPE = Types.repeated(MinorType.MAP);
  public static final MajorType INT_TYPE = Types.optional(MinorType.BIGINT);
  public static final MajorType REPEATED_INT_TYPE = Types.repeated(MinorType.BIGINT);
  public static final MajorType FLOAT_TYPE = Types.optional(MinorType.FLOAT4);
  public static final MajorType REPEATED_FLOAT_TYPE = Types.repeated(MinorType.FLOAT4);
  public static final MajorType NULL_TYPE = Types.optional(MinorType.LATE);

  public static MajorType getFieldType(JsonToken token, boolean repeated) {
    if (repeated) {
      switch (token) {
        case VALUE_STRING:
          return REPEATED_STRING_TYPE;
        case VALUE_FALSE:
        case VALUE_TRUE:
          return REPEATED_BOOLEAN_TYPE;
        case START_ARRAY:
          return ARRAY_TYPE;
        case START_OBJECT:
          return MAP_TYPE;
        case VALUE_NUMBER_INT:
          return REPEATED_INT_TYPE;
        case VALUE_NUMBER_FLOAT:
          return REPEATED_FLOAT_TYPE;
      }
    } else {

      switch (token) {
        case VALUE_STRING:
          return STRING_TYPE;
        case VALUE_FALSE:
        case VALUE_TRUE:
          return BOOLEAN_TYPE;
        case START_ARRAY:
          return ARRAY_TYPE;
        case START_OBJECT:
          return MAP_TYPE;
        case VALUE_NUMBER_INT:
          return INT_TYPE;
        case VALUE_NUMBER_FLOAT:
          return FLOAT_TYPE;
        case VALUE_NULL:
          return NULL_TYPE;
      }
    }

    throw new UnsupportedOperationException("Unsupported Jackson type: " + token + ", Repeated: " + repeated);
  }

  public static Object getValueFromFieldType(JsonParser parser, MinorType fieldType) throws IOException {
    switch (fieldType) {
      case BIGINT:
        return parser.getLongValue();
      case VARCHAR:
        return parser.getValueAsString();
      case FLOAT4:
        return parser.getFloatValue();
      case BIT:
        return parser.getBooleanValue();
      case LATE:
      case NULL:
        return null;
      default:
        throw new RuntimeException("Unexpected Field type to return value: " + fieldType.toString());
    }
  }
}