/*****************************************************************
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.cayenne.query;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import org.apache.cayenne.map.EntityResolver;
import org.apache.cayenne.map.ObjAttribute;
import org.apache.cayenne.map.ObjEntity;
import org.apache.cayenne.reflect.ClassDescriptor;
/**
* A metadata object that provides mapping of a set of result columns to an ObjEntity.
* Used by {@link SQLResultSetMapping}.
*
* @since 3.0
*/
public class EntityResult {
protected String entityName;
protected Class<?> entityClass;
protected Collection<FieldResult> fields;
public EntityResult(Class<?> entityClass) {
this.entityClass = entityClass;
}
public EntityResult(String entityName) {
this.entityName = entityName;
}
public ClassDescriptor getClassDescriptor(EntityResolver resolver) {
return resolver.getClassDescriptor(getRootEntity(resolver).getName());
}
/**
* Returns a map of result column names to attribute db paths from the root entity.
*/
public Map<String, String> getDbFields(EntityResolver resolver) {
if (this.fields == null) {
return Collections.EMPTY_MAP;
}
Map<String, String> dbFields = new HashMap<String, String>();
for (FieldResult field : fields) {
if (field.isDbAttribute()) {
dbFields.put(field.getAttributeName(), field.getColumn());
}
else {
ObjEntity entity = field.getEntityName() != null ? resolver
.getObjEntity(field.getEntityName()) : getRootEntity(resolver);
ObjAttribute attribute = (ObjAttribute) entity.getAttribute(field
.getAttributeName());
dbFields.put(attribute.getDbAttributePath(), field.getColumn());
}
}
return dbFields;
}
public ObjEntity getRootEntity(EntityResolver resolver) {
if (entityName != null) {
return resolver.getObjEntity(entityName);
}
else if (entityClass != null) {
return resolver.lookupObjEntity(entityClass);
}
else {
throw new IllegalStateException("Both entity name and class are null");
}
}
/**
* Adds a result set column mapping for a single object property of the root entity.
*/
public void addObjectField(String attributeName, String column) {
addField(new FieldResult(null, attributeName, column, false));
}
/**
* Adds a result set column mapping for a single object property of a specified entity
* that may differ from the root entity if inheritance is involved.
*/
public void addObjectField(String entityName, String attributeName, String column) {
addField(new FieldResult(entityName, attributeName, column, false));
}
/**
* Adds a result set column mapping for a single DbAttribute.
*/
public void addDbField(String dbAttributeName, String column) {
addField(new FieldResult(null, dbAttributeName, column, true));
}
void addField(FieldResult field) {
if (fields == null) {
fields = new ArrayList<FieldResult>();
}
fields.add(field);
}
public String getEntityName() {
return entityName;
}
public Class<?> getEntityClass() {
return entityClass;
}
public Collection<FieldResult> getFields() {
return fields != null ? fields : Collections.EMPTY_LIST;
}
}