/*
* 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.sql;
import java.io.Serializable;
import java.util.List;
import javax.annotation.Nullable;
import javax.annotation.concurrent.Immutable;
import com.google.common.collect.ImmutableList;
import com.mysema.query.BooleanBuilder;
import com.mysema.query.Tuple;
import com.mysema.query.types.CollectionExpression;
import com.mysema.query.types.Expression;
import com.mysema.query.types.ExpressionUtils;
import com.mysema.query.types.Ops;
import com.mysema.query.types.Path;
import com.mysema.query.types.PathImpl;
import com.mysema.query.types.Predicate;
import com.mysema.query.types.ProjectionRole;
import com.mysema.query.types.expr.BooleanExpression;
import com.mysema.query.types.expr.BooleanOperation;
/**
* ForeignKey defines a foreign key on a table to another table
*
* @author tiwe
*
* @param <E>
*/
@Immutable
public final class ForeignKey<E> implements Serializable, ProjectionRole<Tuple> {
private static final long serialVersionUID = 2260578033772289023L;
private final RelationalPath<?> entity;
private final ImmutableList<? extends Path<?>> localColumns;
private final ImmutableList<String> foreignColumns;
@Nullable
private volatile Expression<Tuple> mixin;
public ForeignKey(RelationalPath<?> entity, Path<?> localColumn, String foreignColumn) {
this(entity, ImmutableList.of(localColumn), ImmutableList.of(foreignColumn));
}
public ForeignKey(RelationalPath<?> entity, ImmutableList<? extends Path<?>> localColumns,
ImmutableList<String> foreignColumns) {
this.entity = entity;
this.localColumns = localColumns;
this.foreignColumns = foreignColumns;
}
public RelationalPath<?> getEntity() {
return entity;
}
public List<? extends Path<?>> getLocalColumns() {
return localColumns;
}
public List<String> getForeignColumns() {
return foreignColumns;
}
@SuppressWarnings("unchecked")
public Predicate on(RelationalPath<E> entity) {
BooleanBuilder builder = new BooleanBuilder();
for (int i = 0; i < localColumns.size(); i++) {
Expression<Object> local = (Expression<Object>)localColumns.get(i);
Expression<?> foreign = new PathImpl(local.getType(), entity, foreignColumns.get(i));
builder.and(ExpressionUtils.eq(local,foreign));
}
return builder.getValue();
}
public BooleanExpression in(CollectionExpression<?,Tuple> coll) {
return BooleanOperation.create(Ops.IN, getProjection(), coll);
}
@Override
public Expression<Tuple> getProjection() {
if (mixin == null) {
mixin = ExpressionUtils.list(Tuple.class, localColumns);
}
return mixin;
}
}