/**
* Copyright 2011 the original author or authors.
*
* 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.springframework.data.neo4j.fieldaccess;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.Path;
import org.neo4j.graphdb.Relationship;
import org.neo4j.graphdb.traversal.TraversalDescription;
import org.springframework.dao.InvalidDataAccessApiUsageException;
import org.springframework.data.neo4j.annotation.GraphTraversal;
import org.springframework.data.neo4j.core.FieldTraversalDescriptionBuilder;
import org.springframework.data.neo4j.core.NodeBacked;
import org.springframework.data.neo4j.core.RelationshipBacked;
import org.springframework.data.neo4j.mapping.Neo4JPersistentProperty;
import org.springframework.data.neo4j.support.GenericTypeExtractor;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import static org.springframework.data.neo4j.support.DoReturn.doReturn;
public class TraversalFieldAccessorFactory implements FieldAccessorFactory<NodeBacked> {
@Override
public boolean accept(final Neo4JPersistentProperty f) {
final GraphTraversal graphEntityTraversal = f.getAnnotation(GraphTraversal.class);
return graphEntityTraversal != null
&& graphEntityTraversal.traversalBuilder() != FieldTraversalDescriptionBuilder.class
&& f.getType().equals(Iterable.class);
}
@Override
public FieldAccessor<NodeBacked> forField(final Neo4JPersistentProperty property) {
return new TraversalFieldAccessor(property);
}
/**
* @author Michael Hunger
* @since 12.09.2010
*/
public static class TraversalFieldAccessor implements FieldAccessor<NodeBacked> {
protected final Neo4JPersistentProperty property;
private final FieldTraversalDescriptionBuilder fieldTraversalDescriptionBuilder;
private Class<?> target;
protected String[] params;
public TraversalFieldAccessor(final Neo4JPersistentProperty property) {
this.property = property;
final GraphTraversal graphEntityTraversal = property.getAnnotation(GraphTraversal.class);
this.target = resolveTarget(graphEntityTraversal,property);
this.params = graphEntityTraversal.params();
this.fieldTraversalDescriptionBuilder = createTraversalDescription(graphEntityTraversal);
}
private Class<?> resolveTarget(GraphTraversal graphTraversal, Neo4JPersistentProperty property) {
if (!graphTraversal.elementClass().equals(NodeBacked.class)) return graphTraversal.elementClass();
final Class<?> result = property.getTypeInformation().getActualType().getType();
Class<?>[] allowedTypes={NodeBacked.class,RelationshipBacked.class,Node.class,Relationship.class, Path.class};
if (!checkTypes(result,allowedTypes)) throw new IllegalArgumentException("The target result type "+result+" of the traversal is no subclass of the allowed types: "+property+" "+allowedTypes);
return result;
}
private boolean checkTypes(Class<?> target, Class<?>...allowedTypes) {
for (Class<?> type : allowedTypes) {
if (type.isAssignableFrom(target)) return true;
}
return false;
}
@Override
public boolean isWriteable(NodeBacked nodeBacked) {
return false;
}
@Override
public Object setValue(final NodeBacked nodeBacked, final Object newVal) {
throw new InvalidDataAccessApiUsageException("Cannot set readonly traversal description field " + property);
}
@Override
public Object getValue(final NodeBacked nodeBacked) {
final TraversalDescription traversalDescription = fieldTraversalDescriptionBuilder.build(nodeBacked, property,params);
return doReturn(nodeBacked.findAllByTraversal(target, traversalDescription));
}
private FieldTraversalDescriptionBuilder createTraversalDescription(final GraphTraversal graphEntityTraversal) {
try {
final Class<? extends FieldTraversalDescriptionBuilder> traversalDescriptionClass = graphEntityTraversal.traversalBuilder();
final Constructor<? extends FieldTraversalDescriptionBuilder> constructor = traversalDescriptionClass.getDeclaredConstructor();
constructor.setAccessible(true);
return constructor.newInstance();
} catch (Exception e) {
throw new RuntimeException("Error creating TraversalDescription from " + property,e);
}
}
@Override
public Object getDefaultImplementation() {
return null;
}
}
}