com.amazonaws.services.simpleworkflow.flow.JsonDataConverter Maven / Gradle / Ivy
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/*
* Copyright 2012-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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 com.amazonaws.services.simpleworkflow.flow;
import java.io.IOException;
import com.fasterxml.jackson.core.JsonGenerationException;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.ObjectMapper.DefaultTyping;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.DeserializationFeature;
/**
* Implements conversion through Jackson JSON processor. Consult its
* documentation on how to ensure that classes are serializable, configure their
* serialization through annotations and {@link ObjectMapper} parameters.
*
*
* Note that default configuration used by this class includes class name of the
* every serialized value into the produced JSON. It is done to support
* polymorphic types out of the box. But in some cases it might be beneficial to
* disable polymorphic support as it produces much more concise and portable
* output.
*
* @author fateev
*/
public class JsonDataConverter extends DataConverter {
protected final ObjectMapper mapper;
/**
* Create instance of the converter that uses ObjectMapper with
* {@link Feature#FAIL_ON_UNKNOWN_PROPERTIES} set to false and
* default typing set to {@link DefaultTyping#NON_FINAL}.
*/
public JsonDataConverter() {
this(new ObjectMapper());
// ignoring unknown properties makes us more robust to changes in the schema
mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
mapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
// This will allow including type information all non-final types. This allows correct
// serialization/deserialization of generic collections, for example List.
mapper.enableDefaultTyping(DefaultTyping.NON_FINAL);
}
/**
* Create instance of the converter that uses {@link ObjectMapper}
* configured externally.
*/
public JsonDataConverter(ObjectMapper mapper) {
this.mapper = mapper;
}
@Override
public String toData(Object value) throws DataConverterException {
try {
return mapper.writeValueAsString(value);
}
catch (JsonGenerationException e) {
throwDataConverterException(e, value);
}
catch (JsonMappingException e) {
throwDataConverterException(e, value);
}
catch (IOException e) {
throwDataConverterException(e, value);
}
throw new IllegalStateException("not reachable");
}
private void throwDataConverterException(Throwable e, Object value) {
if (value == null) {
throw new DataConverterException("Failure serializing null value", e);
}
throw new DataConverterException("Failure serializing \"" + value + "\" of type \"" + value.getClass() + "\"", e);
}
@Override
public T fromData(String serialized, Class valueType) throws DataConverterException {
try {
return mapper.readValue(serialized, valueType);
}
catch (JsonParseException e) {
throw new DataConverterException(e);
}
catch (JsonMappingException e) {
throw new DataConverterException(e);
}
catch (IOException e) {
throw new DataConverterException(e);
}
}
}