/*
* Copyright (C) 2015 Red Hat, Inc. and/or its affiliates.
*
* 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.jboss.errai.jpa.client.local;
import javax.persistence.Parameter;
import javax.persistence.TypedQuery;
import org.jboss.errai.common.client.api.Assert;
import com.google.common.collect.ImmutableBiMap;
/**
* Factory class for creating TypedQuery instances. Used internally by
* EntityManager's <i>createXXXQuery</i> methods.
*
* @author Jonathan Fuerth <jfuerth@gmail.com>
*/
public abstract class TypedQueryFactory {
protected final Class<?> actualResultType;
protected final ImmutableBiMap<String, Parameter<?>> parameters;
public TypedQueryFactory(
Class<?> actualResultType,
ErraiParameter<?>[] parameters) {
this.actualResultType = Assert.notNull(actualResultType);
ImmutableBiMap.Builder<String, Parameter<?>> pb = ImmutableBiMap.builder();
for (Parameter<?> p : parameters) {
pb.put(p.getName(), p);
}
this.parameters = pb.build();
}
/**
* Creates an instance of the TypedQuery associated with this factory if its
* result type is assignable to the given type.
*
* @param resultType
* The expected result type
* @param entityManager
* the EntityManager the query will be executed in. Must not be null.
* @param <T>
* The result type of the queries produced by this factory
* @return A new instance of TypedQuery, whose result type is assignable to
* {@code resultType}.
* @throws IllegalArgumentException
* if the query's result type is not assignable to the given type.
*/
public <T> TypedQuery<T> createIfCompatible(Class<T> resultType, ErraiEntityManager entityManager) {
Class<?> resultSupertype = actualResultType;
while (resultSupertype != null) {
if (resultType == resultSupertype) {
return createQuery(entityManager);
}
resultSupertype = resultSupertype.getSuperclass();
}
throw new IllegalArgumentException("Expected return type " + resultType + " is not assignable from actual return type " + actualResultType);
}
/**
* Subclasses must implement this method by returning a new instance of
* ErraiTypedQuery that implements the query logic for the JPA query handled
* by this factory.
*
* @param the
* EntityManager the query will be executed in. Must not be null.
* @return a new instance of ErraiTypedQuery.
*/
protected abstract <T> TypedQuery<T> createQuery(ErraiEntityManager entityManager);
}