| /* |
| * 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.openjpa.kernel.exps; |
| |
| import java.util.Collection; |
| |
| import org.apache.openjpa.kernel.Filters; |
| import org.apache.openjpa.kernel.StoreContext; |
| |
| /** |
| * Expression that compares two others. |
| * |
| * @author Abe White |
| */ |
| abstract class CompareExpression |
| extends Exp { |
| |
| private final Val _val1; |
| private final Val _val2; |
| |
| /** |
| * Constructor. Supply values to compare. |
| */ |
| public CompareExpression(Val val1, Val val2) { |
| _val1 = val1; |
| _val2 = val2; |
| } |
| |
| protected boolean eval(Object candidate, Object orig, |
| StoreContext ctx, Object[] params) { |
| Object o1 = _val1.eval(candidate, orig, ctx, params); |
| Object o2 = _val2.eval(candidate, orig, ctx, params); |
| if (o1 != null && o2 != null) { |
| Class c = Filters.promote(o1.getClass(), o2.getClass()); |
| o1 = Filters.convert(o1, c); |
| o2 = Filters.convert(o2, c); |
| } |
| return compare(o1, o2); |
| } |
| |
| protected boolean eval(Collection candidates, StoreContext ctx, |
| Object[] params) { |
| Collection c1 = _val1.eval(candidates, null, ctx, params); |
| Collection c2 = _val2.eval(candidates, null, ctx, params); |
| Object o1 = (c1 == null || c1.isEmpty()) ? null |
| : c1.iterator().next(); |
| Object o2 = (c2 == null || c2.isEmpty()) ? null |
| : c2.iterator().next(); |
| |
| if (o1 != null && o2 != null) { |
| Class c = Filters.promote(o1.getClass(), o2.getClass()); |
| o1 = Filters.convert(o1, c); |
| o2 = Filters.convert(o2, c); |
| } |
| return compare(o1, o2); |
| } |
| |
| /** |
| * Compare the two values. |
| */ |
| protected abstract boolean compare(Object o1, Object o2); |
| |
| public void acceptVisit(ExpressionVisitor visitor) { |
| visitor.enter(this); |
| _val1.acceptVisit(visitor); |
| _val2.acceptVisit(visitor); |
| visitor.exit(this); |
| } |
| } |