lang/java/ipc/src/test/java/org/apache/avro/TestDataFileSpecific.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.avro;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import org.apache.avro.file.DataFileReader;
import org.apache.avro.file.DataFileWriter;
import org.apache.avro.generic.GenericData.Record;
import org.apache.avro.generic.GenericDatumWriter;
import org.apache.avro.specific.SpecificDatumReader;

import org.junit.Assert;
import org.junit.Test;

import org.apache.avro.Foo;

public class TestDataFileSpecific {

  private static final File DIR =
    new File(System.getProperty("test.dir","/tmp"));
  private static final File FILE = new File(DIR, "specific.avro");

  /* Test when using SpecificDatumReader<T>() constructor to read from a file
   * with a different schema that both reader & writer schemas are found.*/
  @Test
  public void testSpecificDatumReaderDefaultCtor() throws IOException {
    // like the specific Foo, but with another field
    Schema s1 = Schema.parse("{\"type\":\"record\",\"name\":\"Foo\","
                             +"\"namespace\":\"org.apache.avro\",\"fields\":["
                             +"{\"name\":\"label\",\"type\":\"string\"},"
                             +"{\"name\":\"id\",\"type\":\"int\"}]}");

    // write a file using generic objects
    DataFileWriter<Record> writer
      = new DataFileWriter<Record>(new GenericDatumWriter<Record>(s1))
      .create(s1, FILE);
    for (int i = 0; i < 10; i++) {
      Record r = new Record(s1);
      r.put("label", ""+i);
      r.put("id", i);
      writer.append(r);
    }
    writer.close();

    // read using a 'new SpecificDatumReader<T>()' to force inference of
    // reader's schema from runtime
    DataFileReader<Foo> reader =
      new DataFileReader<Foo>(FILE, new SpecificDatumReader<Foo>());
    int i = 0;
    for (Foo f : reader)
      Assert.assertEquals(""+(i++), f.getLabel().toString());
    Assert.assertEquals(10, i);
    reader.close();
  }

}