| /** |
| * 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.hadoop.tools.rumen; |
| |
| import java.io.Closeable; |
| import java.io.EOFException; |
| import java.io.IOException; |
| import java.io.InputStream; |
| |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.fs.Path; |
| import org.codehaus.jackson.JsonParser; |
| import org.codehaus.jackson.map.DeserializationConfig; |
| import org.codehaus.jackson.map.ObjectMapper; |
| |
| /** |
| * A simple wrapper for parsing JSON-encoded data using ObjectMapper. |
| * |
| * @param <T> |
| * The (base) type of the object(s) to be parsed by this parser. |
| */ |
| class JsonObjectMapperParser<T> implements Closeable { |
| private final ObjectMapper mapper; |
| private final Class<? extends T> clazz; |
| private final JsonParser jsonParser; |
| |
| /** |
| * Constructor. |
| * |
| * @param path |
| * Path to the JSON data file, possibly compressed. |
| * @param conf |
| * @throws IOException |
| */ |
| public JsonObjectMapperParser(Path path, Class<? extends T> clazz, |
| Configuration conf) throws IOException { |
| mapper = new ObjectMapper(); |
| mapper.configure( |
| DeserializationConfig.Feature.CAN_OVERRIDE_ACCESS_MODIFIERS, true); |
| this.clazz = clazz; |
| InputStream input = new PossiblyDecompressedInputStream(path, conf); |
| jsonParser = mapper.getJsonFactory().createJsonParser(input); |
| } |
| |
| /** |
| * Constructor. |
| * |
| * @param input |
| * The input stream for the JSON data. |
| */ |
| public JsonObjectMapperParser(InputStream input, Class<? extends T> clazz) |
| throws IOException { |
| mapper = new ObjectMapper(); |
| mapper.configure( |
| DeserializationConfig.Feature.CAN_OVERRIDE_ACCESS_MODIFIERS, true); |
| this.clazz = clazz; |
| jsonParser = mapper.getJsonFactory().createJsonParser(input); |
| } |
| |
| /** |
| * Get the next object from the trace. |
| * |
| * @return The next instance of the object. Or null if we reach the end of |
| * stream. |
| * @throws IOException |
| */ |
| public T getNext() throws IOException { |
| try { |
| return mapper.readValue(jsonParser, clazz); |
| } catch (EOFException e) { |
| return null; |
| } |
| } |
| |
| @Override |
| public void close() throws IOException { |
| jsonParser.close(); |
| } |
| } |