org.bndly.common.graph.FieldAnnotationBasedIdentityExtractor Maven / Gradle / Ivy
package org.bndly.common.graph;
/*-
* #%L
* Graph Impl
* %%
* Copyright (C) 2013 - 2020 Cybercon GmbH
* %%
* 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.
* #L%
*/
import org.bndly.common.reflection.ReflectionUtil;
import org.bndly.common.graph.api.IDExtractor;
import org.bndly.common.graph.api.Identity;
import java.lang.annotation.Annotation;
import java.lang.reflect.Field;
public class FieldAnnotationBasedIdentityExtractor implements IDExtractor {
private final Class markerType;
public FieldAnnotationBasedIdentityExtractor(Class markerType) {
this.markerType = markerType;
}
@Override
public Identity getId(E source) {
Field field = ReflectionUtil.getFieldByAnnotation(markerType, source);
if (field != null) {
final Object id = ReflectionUtil.getFieldValue(field, source);
final Class type = field.getDeclaringClass();
return new Identity() {
@Override
public Object getValue() {
return id;
}
@Override
public Class getIdentityForType() {
return type;
}
};
} else {
return null;
}
}
}