org.nd4j.serde.json.BaseLegacyDeserializer Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2015-2018 Skymind, Inc.
*
* This program and the accompanying materials are made available under the
* terms of the Apache License, Version 2.0 which is available at
* https://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.
*
* SPDX-License-Identifier: Apache-2.0
******************************************************************************/
package org.nd4j.serde.json;
import lombok.extern.slf4j.Slf4j;
import org.nd4j.shade.jackson.core.JsonParser;
import org.nd4j.shade.jackson.databind.DeserializationContext;
import org.nd4j.shade.jackson.databind.JsonDeserializer;
import org.nd4j.shade.jackson.databind.JsonNode;
import org.nd4j.shade.jackson.databind.ObjectMapper;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
/**
* A base deserialization class used to handle deserializing of a specific class given changes from subtype wrapper
* format to class field format.
* That is: from...
* {@literal {@code @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.WRAPPER_OBJECT)}}
* {@literal {@code @JsonSubTypes(value = {@JsonSubTypes.Type(value = LossBinaryXENT.class, name = "BinaryXENT"),}...}}
*
* to
*
* {@literal {@code @JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include = JsonTypeInfo.As.PROPERTY, property = "@class")}}
*
* @param Type to deserialize
* @author Alex Black
*/
@Slf4j
public abstract class BaseLegacyDeserializer extends JsonDeserializer {
public abstract Map getLegacyNamesMap();
public abstract ObjectMapper getLegacyJsonMapper();
public abstract Class getDeserializedType();
@Override
public T deserialize(JsonParser jp, DeserializationContext deserializationContext) throws IOException {
//Manually parse old format
JsonNode node = jp.getCodec().readTree(jp);
Iterator> nodes = node.fields();
List> list = new ArrayList<>();
while(nodes.hasNext()){
list.add(nodes.next());
}
if(list.size() != 1){
//Should only occur if field is null?
return null;
}
String name = list.get(0).getKey();
JsonNode value = list.get(0).getValue();
Map legacyNamesMap = getLegacyNamesMap();
String layerClass = legacyNamesMap.get(name);
if(layerClass == null){
throw new IllegalStateException("Cannot deserialize " + getDeserializedType() + " with name \"" + name
+ "\": legacy class mapping with this name is unknown");
}
Class lClass;
try {
lClass = (Class) Class.forName(layerClass);
} catch (Exception e){
throw new RuntimeException("Could not find class for deserialization of \"" + name + "\" of type " +
getDeserializedType() + ": class " + layerClass + " is not on the classpath?", e);
}
ObjectMapper m = getLegacyJsonMapper();
if(m == null){
//Should never happen, unless the user is doing something unusual
throw new IllegalStateException("Cannot deserialize unknown subclass of type " +
getDeserializedType() + ": no legacy JSON mapper has been set");
}
String nodeAsString = value.toString();
try {
T t = m.readValue(nodeAsString, lClass);
return t;
} catch (Throwable e){
throw new IllegalStateException("Cannot deserialize legacy JSON format of object with name \"" + name
+ "\" of type " + getDeserializedType().getName(), e);
}
}
}