org.camunda.spin.impl.json.jackson.format.ListJacksonJsonTypeDetector Maven / Gradle / Ivy
/*
* Copyright © 2014 - 2018 camunda services GmbH and various authors ([email protected])
*
* Licensed 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.camunda.spin.impl.json.jackson.format;
import java.lang.reflect.TypeVariable;
import java.util.List;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.type.TypeFactory;
public class ListJacksonJsonTypeDetector extends AbstractJacksonJsonTypeDetector {
public boolean canHandle(Object object) {
return object instanceof List;
}
public String detectType(Object object) {
return constructType(object).toCanonical();
}
protected JavaType constructType(Object object) {
TypeFactory typeFactory = TypeFactory.defaultInstance();
if (object instanceof List && !((List) object).isEmpty()) {
List list = (List) object;
Object firstElement = list.get(0);
if (bindingsArePresent(list.getClass())) {
final JavaType elementType = constructType(firstElement);
return typeFactory.constructCollectionType(list.getClass(), elementType);
}
}
return typeFactory.constructType(object.getClass());
}
private boolean bindingsArePresent(Class erasedType) {
TypeVariable[] vars = erasedType.getTypeParameters();
int varLen = (vars == null) ? 0 : vars.length;
if (varLen == 0) {
return false;
}
if (varLen != 1) {
throw new IllegalArgumentException("Cannot create TypeBindings for class " + erasedType.getName() + " with 1 type parameter: class expects " + varLen);
}
return true;
}
}