/*
* Copyright 2011, Mysema Ltd
*
* 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 com.mysema.query.support;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import javax.annotation.Nullable;
import com.mysema.commons.lang.CloseableIterator;
import com.mysema.commons.lang.IteratorAdapter;
import com.mysema.query.NonUniqueResultException;
import com.mysema.query.Projectable;
import com.mysema.query.ResultTransformer;
import com.mysema.query.Tuple;
import com.mysema.query.types.Expression;
/**
* ProjectableQuery extends the {@link QueryBase} class to provide default
* implementations of the methods of the {@link Projectable} interface
*
* @author tiwe
*/
public abstract class ProjectableQuery<Q extends ProjectableQuery<Q>>
extends QueryBase<Q> implements Projectable {
public ProjectableQuery(QueryMixin<Q> queryMixin) {
super(queryMixin);
}
@Override
public List<Tuple> list(Expression<?>... args) {
return IteratorAdapter.asList(iterate(args));
}
@Override
public <RT> List<RT> list(Expression<RT> projection) {
return IteratorAdapter.asList(iterate(projection));
}
@Override
public final <K, V> Map<K, V> map(Expression<K> key, Expression<V> value) {
List<Tuple> list = list(key, value);
Map<K, V> results = new LinkedHashMap<K, V>(list.size());
for (Tuple row : list) {
results.put(row.get(key), row.get(value));
}
return results;
}
@Override
public final boolean notExists() {
return !exists();
}
@Override
public final Tuple singleResult(Expression<?>... args) {
return limit(1).uniqueResult(args);
}
@Override
public final <RT> RT singleResult(Expression<RT> expr) {
return limit(1).uniqueResult(expr);
}
@Override
public <T> T transform(ResultTransformer<T> transformer) {
return transformer.transform(this);
}
@Nullable
protected <T> T uniqueResult(CloseableIterator<T> it) {
try{
if (it.hasNext()) {
T rv = it.next();
if (it.hasNext()) {
throw new NonUniqueResultException();
}
return rv;
} else {
return null;
}
}finally{
it.close();
}
}
}