Java GenericsUtil类代码示例

import org.apache.hadoop.util.GenericsUtil; //导入依赖的package包/类
/**
 * Stores the array of items in the configuration with the given keyName.
 * 
 * @param <K> the class of the item
 * @param conf the configuration to use 
 * @param items the objects to be stored
 * @param keyName the name of the key to use
 * @throws IndexOutOfBoundsException if the items array is empty
 * @throws IOException : forwards Exceptions from the underlying 
 * {@link Serialization} classes.         
 */
public static <K> void storeArray(Configuration conf, K[] items,
    String keyName) throws IOException {

  DefaultStringifier<K> stringifier = new DefaultStringifier<K>(conf, 
      GenericsUtil.getClass(items[0]));
  try {
    StringBuilder builder = new StringBuilder();
    for (K item : items) {
      builder.append(stringifier.toString(item)).append(SEPARATOR);
    }
    conf.set(keyName, builder.toString());
  }
  finally {
    stringifier.close();
  }
}
 

import org.apache.hadoop.util.GenericsUtil; //导入依赖的package包/类
/**
 * Restores the array of objects from the configuration.
 * 
 * @param <K> the class of the item
 * @param conf the configuration to use
 * @param keyName the name of the key to use
 * @param itemClass the class of the item
 * @return restored object
 * @throws IOException : forwards Exceptions from the underlying 
 * {@link Serialization} classes.
 */
public static <K> K[] loadArray(Configuration conf, String keyName,
    Class<K> itemClass) throws IOException {
  DefaultStringifier<K> stringifier = new DefaultStringifier<K>(conf,
      itemClass);
  try {
    String itemStr = conf.get(keyName);
    ArrayList<K> list = new ArrayList<K>();
    String[] parts = itemStr.split(SEPARATOR);

    for (String part : parts) {
      if (!part.isEmpty())
        list.add(stringifier.fromString(part));
    }

    return GenericsUtil.toArray(itemClass, list);
  }
  finally {
    stringifier.close();
  }
}
 

import org.apache.hadoop.util.GenericsUtil; //导入依赖的package包/类
/**
 * A utility that tests serialization/deserialization. 
 * @param conf configuration to use, "io.serializations" is read to 
 * determine the serialization
 * @param <K> the class of the item
 * @param before item to (de)serialize
 * @return deserialized item
 */
public static <K> K testSerialization(Configuration conf, K before)
	throws Exception {

  SerializationFactory factory = new SerializationFactory(conf);
  Serializer<K> serializer 
    = factory.getSerializer(GenericsUtil.getClass(before));
  Deserializer<K> deserializer 
    = factory.getDeserializer(GenericsUtil.getClass(before));

  DataOutputBuffer out = new DataOutputBuffer();
  serializer.open(out);
  serializer.serialize(before);
  serializer.close();

  DataInputBuffer in = new DataInputBuffer();
  in.reset(out.getData(), out.getLength());
  deserializer.open(in);
  K after = deserializer.deserialize(null);
  deserializer.close();
  return after;
}
 

import org.apache.hadoop.util.GenericsUtil; //导入依赖的package包/类
private <K> K serDeser(K conf) throws Exception {
  SerializationFactory factory = new SerializationFactory(CONF);
  Serializer<K> serializer =
    factory.getSerializer(GenericsUtil.getClass(conf));
  Deserializer<K> deserializer =
    factory.getDeserializer(GenericsUtil.getClass(conf));

  DataOutputBuffer out = new DataOutputBuffer();
  serializer.open(out);
  serializer.serialize(conf);
  serializer.close();

  DataInputBuffer in = new DataInputBuffer();
  in.reset(out.getData(), out.getLength());
  deserializer.open(in);
  K after = deserializer.deserialize(null);
  deserializer.close();
  return after;
}
 

import org.apache.hadoop.util.GenericsUtil; //导入依赖的package包/类
private <E> E makeCopyForPassByValue(Serialization<E> serialization,
                                      E obj) throws IOException {
  Serializer<E> ser =
    serialization.getSerializer(GenericsUtil.getClass(obj));
  Deserializer<E> deser =
    serialization.getDeserializer(GenericsUtil.getClass(obj));

  DataOutputBuffer dof = threadLocalDataOutputBuffer.get();

  dof.reset();
  ser.open(dof);
  ser.serialize(obj);
  ser.close();
  obj = ReflectionUtils.newInstance(GenericsUtil.getClass(obj),
                                    getChainJobConf());
  ByteArrayInputStream bais =
    new ByteArrayInputStream(dof.getData(), 0, dof.getLength());
  deser.open(bais);
  deser.deserialize(obj);
  deser.close();
  return obj;
}
 

import org.apache.hadoop.util.GenericsUtil; //导入依赖的package包/类
/**
 * A utility that tests serialization/deserialization. 
 * @param <K> the class of the item
 * @param conf configuration to use, "io.serializations" is read to 
 * determine the serialization
 * @param before item to (de)serialize
 * @return deserialized item
 */
public static<K> K testSerialization(Configuration conf, K before) 
  throws Exception {
  
  SerializationFactory factory = new SerializationFactory(conf);
  Serializer<K> serializer 
    = factory.getSerializer(GenericsUtil.getClass(before));
  Deserializer<K> deserializer 
    = factory.getDeserializer(GenericsUtil.getClass(before));
 
  DataOutputBuffer out = new DataOutputBuffer();
  serializer.open(out);
  serializer.serialize(before);
  serializer.close();
  
  DataInputBuffer in = new DataInputBuffer();
  in.reset(out.getData(), out.getLength());
  deserializer.open(in);
  K after = deserializer.deserialize(null);
  deserializer.close();
  
  assertEquals(before, after);
  return after;
}
 

import org.apache.hadoop.util.GenericsUtil; //导入依赖的package包/类
/**
 * Restores the array of objects from the configuration.
 * 
 * @param <K> the class of the item
 * @param conf the configuration to use
 * @param keyName the name of the key to use
 * @param itemClass the class of the item
 * @return restored object
 * @throws IOException : forwards Exceptions from the underlying 
 * {@link Serialization} classes.
 */
public static <K> K[] loadArray(Configuration conf, String keyName,
    Class<K> itemClass) throws IOException {
  DefaultStringifier<K> stringifier = new DefaultStringifier<K>(conf,
      itemClass);
  try {
    String itemStr = conf.get(keyName);
    ArrayList<K> list = new ArrayList<K>();
    String[] parts = itemStr.split(SEPARATOR);

    for (String part : parts) {
      if (!part.equals(""))
        list.add(stringifier.fromString(part));
    }

    return GenericsUtil.toArray(itemClass, list);
  }
  finally {
    stringifier.close();
  }
}
 

import org.apache.hadoop.util.GenericsUtil; //导入依赖的package包/类
@Override
public String toString() {
  Configuration conf = new Configuration();
  conf.set("io.serializations",
           "org.apache.hadoop.io.serializer.JavaSerialization,"
           + "org.apache.hadoop.io.serializer.WritableSerialization");
  DefaultStringifier<Map<String,String>> mapStringifier = new DefaultStringifier<Map<String,String>>(conf,
      GenericsUtil.getClass(params));
  try {
    return mapStringifier.toString(params);
  } catch (IOException e) {
    log.info("Encountered IOException while deserializing returning empty string", e);
    return "";
  }
  
}