JoinBuilder.java

/*
 * 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.deltaspike.data.impl.criteria.predicate;

import java.util.List;

import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.From;
import javax.persistence.criteria.Join;
import javax.persistence.criteria.JoinType;
import javax.persistence.criteria.Path;
import javax.persistence.criteria.Predicate;
import javax.persistence.metamodel.CollectionAttribute;
import javax.persistence.metamodel.ListAttribute;
import javax.persistence.metamodel.MapAttribute;
import javax.persistence.metamodel.SetAttribute;
import javax.persistence.metamodel.SingularAttribute;

import org.apache.deltaspike.data.api.criteria.Criteria;

@SuppressWarnings({ "rawtypes", "unchecked" })
public class JoinBuilder<P, R, E> implements PredicateBuilder<P>
{

    private final Criteria<R, R> criteria;
    private final JoinType joinType;

    private SingularAttribute<? super P, R> singular;
    private ListAttribute<? super P, R> list;
    private CollectionAttribute<? super P, R> collection;
    private SetAttribute<? super P, R> set;
    private MapAttribute<? super P, E, R> map;

    public JoinBuilder(Criteria<R, R> criteria, JoinType joinType)
    {
        this.criteria = criteria;
        this.joinType = joinType;
    }

    public JoinBuilder(Criteria<R, R> criteria, JoinType joinType, SingularAttribute<? super P, R> singular)
    {
        this(criteria, joinType);
        this.singular = singular;
    }

    public JoinBuilder(Criteria<R, R> criteria, JoinType joinType, ListAttribute<? super P, R> list)
    {
        this(criteria, joinType);
        this.list = list;
    }

    public JoinBuilder(Criteria<R, R> criteria, JoinType joinType, CollectionAttribute<? super P, R> collection)
    {
        this(criteria, joinType);
        this.collection = collection;
    }

    public JoinBuilder(Criteria<R, R> criteria, JoinType joinType, SetAttribute<? super P, R> set)
    {
        this(criteria, joinType);
        this.set = set;
    }

    public JoinBuilder(Criteria<R, R> criteria, JoinType joinType, MapAttribute<? super P, E, R> map)
    {
        this(criteria, joinType);
        this.map = map;
    }

    @Override
    public List<Predicate> build(CriteriaBuilder builder, Path<P> path)
    {
        Join join = null;
        if (singular != null)
        {
            join = joinSingular((From) path);
        }
        else if (list != null)
        {
            join = joinList((From) path);
        }
        else if (collection != null)
        {
            join = joinCollection((From) path);
        }
        else if (set != null)
        {
            join = joinSet((From) path);
        }
        else
        {
            join = joinMap((From) path);
        }
        return criteria.predicates(builder, join);
    }

    private Join joinSingular(From path)
    {
        if (joinType == null)
        {
            return path.join(singular);
        }
        return path.join(singular, joinType);
    }

    private Join joinList(From path)
    {
        if (joinType == null)
        {
            return path.join(list);
        }
        return path.join(list, joinType);
    }

    private Join joinCollection(From path)
    {
        if (joinType == null)
        {
            return path.join(collection);
        }
        return path.join(collection, joinType);
    }

    private Join joinSet(From path)
    {
        if (joinType == null)
        {
            return path.join(set);
        }
        return path.join(set, joinType);
    }

    private Join joinMap(From path)
    {
        if (joinType == null)
        {
            return path.join(map);
        }
        return path.join(map, joinType);
    }

}