/**
* 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.gora.util;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.avro.Schema;
import org.apache.avro.Schema.Field;
import org.apache.avro.io.BinaryEncoder;
import org.apache.avro.io.Decoder;
import org.apache.avro.io.DecoderFactory;
import org.apache.avro.io.EncoderFactory;
import org.apache.avro.reflect.ReflectData;
import org.apache.avro.specific.SpecificDatumReader;
import org.apache.avro.specific.SpecificDatumWriter;
import org.apache.gora.persistency.Persistent;
/**
* An utility class for Avro related tasks
*/
public class AvroUtils {
/**
* Returns a map of field name to Field for schema's fields.
*/
public static Map<String, Field> getFieldMap(Schema schema) {
List<Field> fields = schema.getFields();
HashMap<String, Field> fieldMap = new HashMap<String, Field>(fields.size());
for (Field field : fields) {
fieldMap.put(field.name(), field);
}
return fieldMap;
}
@SuppressWarnings("unchecked")
public static Object getEnumValue(Schema schema, String symbol) {
return Enum.valueOf(ReflectData.get().getClass(schema), symbol);
}
public static Object getEnumValue(Schema schema, int enumOrdinal) {
String symbol = schema.getEnumSymbols().get(enumOrdinal);
return getEnumValue(schema, symbol);
}
/**
* Returns the schema of the class
*/
public static Schema getSchema(Class<? extends Persistent> clazz)
throws SecurityException, NoSuchFieldException, IllegalArgumentException,
IllegalAccessException {
java.lang.reflect.Field field = clazz.getDeclaredField("SCHEMA$");
return (Schema) field.get(null);
}
/**
* Return the field names from a persistent object
*
* @param persistent
* the persistent object to get the fields names from
* @return the field names
*/
public static String[] getPersistentFieldNames(Persistent persistent) {
return getSchemaFieldNames(persistent.getSchema());
}
/**
* Return the field names from a schema object
*
* @param persistent
* the persistent object to get the fields names from
* @return the field names
*/
public static String[] getSchemaFieldNames(Schema schema) {
List<Field> fields = schema.getFields();
String[] fieldNames = new String[fields.size() - 1];
for (int i = 0; i < fieldNames.length; i++) {
fieldNames[i] = fields.get(i + 1).name();
}
return fieldNames;
}
public static <T extends Persistent> T deepClonePersistent(T persistent) {
ByteArrayOutputStream bos = new ByteArrayOutputStream();
BinaryEncoder enc = EncoderFactory.get().binaryEncoder(bos, null);
SpecificDatumWriter<Persistent> writer = new SpecificDatumWriter<Persistent>(
persistent.getSchema());
try {
writer.write(persistent, enc);
} catch (IOException e) {
throw new RuntimeException(
"Unable to serialize avro object to byte buffer - "
+ "please report this issue to the Gora bugtracker "
+ "or your administrator.");
}
byte[] value = bos.toByteArray();
Decoder dec = DecoderFactory.get().binaryDecoder(value, null);
@SuppressWarnings("unchecked")
SpecificDatumReader<T> reader = new SpecificDatumReader<T>(
(Class<T>) persistent.getClass());
try {
return reader.read(null, dec);
} catch (IOException e) {
throw new RuntimeException(
"Unable to deserialize avro object from byte buffer - "
+ "please report this issue to the Gora bugtracker "
+ "or your administrator.");
}
}
}