org.apache.hadoop.registry.client.binding.JsonSerDeser Maven / Gradle / Ivy
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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.hadoop.registry.client.binding;
import com.fasterxml.jackson.core.JsonProcessingException;
import org.apache.commons.lang3.StringUtils;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.registry.client.exceptions.InvalidRecordException;
import org.apache.hadoop.registry.client.exceptions.NoRecordException;
import org.apache.hadoop.util.JsonSerialization;
import java.io.EOFException;
import java.io.IOException;
/**
* Support for marshalling objects to and from JSON.
*
* This extends {@link JsonSerialization} with the notion
* of a marker field in the JSON file, with
*
* - a fail-fast check for it before even trying to parse.
* - Specific IOException subclasses for a failure.
*
* The rationale for this is not only to support different things in the,
* registry, but the fact that all ZK nodes have a size > 0 when examined.
*
* @param Type to marshal.
*/
@InterfaceAudience.Private
@InterfaceStability.Evolving
public class JsonSerDeser extends JsonSerialization {
private static final String UTF_8 = "UTF-8";
public static final String E_NO_DATA = "No data at path";
public static final String E_DATA_TOO_SHORT = "Data at path too short";
public static final String E_MISSING_MARKER_STRING =
"Missing marker string: ";
/**
* Create an instance bound to a specific type
* @param classType class to marshall
*/
public JsonSerDeser(Class classType) {
super(classType, false, false);
}
/**
* Deserialize from a byte array
* @param path path the data came from
* @param bytes byte array
* @throws IOException all problems
* @throws EOFException not enough data
* @throws InvalidRecordException if the parsing failed -the record is invalid
* @throws NoRecordException if the data is not considered a record: either
* it is too short or it did not contain the marker string.
*/
public T fromBytes(String path, byte[] bytes) throws IOException {
return fromBytes(path, bytes, "");
}
/**
* Deserialize from a byte array, optionally checking for a marker string.
*
* If the marker parameter is supplied (and not empty), then its presence
* will be verified before the JSON parsing takes place; it is a fast-fail
* check. If not found, an {@link InvalidRecordException} exception will be
* raised
* @param path path the data came from
* @param bytes byte array
* @param marker an optional string which, if set, MUST be present in the
* UTF-8 parsed payload.
* @return The parsed record
* @throws IOException all problems
* @throws EOFException not enough data
* @throws InvalidRecordException if the JSON parsing failed.
* @throws NoRecordException if the data is not considered a record: either
* it is too short or it did not contain the marker string.
*/
public T fromBytes(String path, byte[] bytes, String marker)
throws IOException {
int len = bytes.length;
if (len == 0 ) {
throw new NoRecordException(path, E_NO_DATA);
}
if (StringUtils.isNotEmpty(marker) && len < marker.length()) {
throw new NoRecordException(path, E_DATA_TOO_SHORT);
}
String json = new String(bytes, 0, len, UTF_8);
if (StringUtils.isNotEmpty(marker)
&& !json.contains(marker)) {
throw new NoRecordException(path, E_MISSING_MARKER_STRING + marker);
}
try {
return fromJson(json);
} catch (JsonProcessingException e) {
throw new InvalidRecordException(path, e.toString(), e);
}
}
}