| /* |
| * 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.oodt.profile.handlers.lightweight; |
| |
| import java.util.HashSet; |
| import java.util.Map; |
| |
| /** |
| * A constant expression. |
| * |
| * This expression yields either all the elements (if it's a constant true) or none (if |
| * it's a constant false). |
| * |
| * @author Kelly |
| */ |
| class ConstantExpression implements WhereExpression { |
| /** |
| * Construct a constant where-expression. |
| * |
| * @param value Truth value of this expression. |
| */ |
| public ConstantExpression(boolean value) { |
| this.value = value; |
| } |
| |
| public Result result(SearchableResourceAttributes resAttr, Map elements) { |
| if (value) |
| return new MatchingResult(new HashSet(elements.values())); |
| else |
| return FalseResult.INSTANCE; |
| } |
| |
| public WhereExpression simplify() { |
| // Can't get simpler than this. |
| return this; |
| } |
| |
| public WhereExpression negate() { |
| return new ConstantExpression(!value); |
| } |
| |
| public String toString() { |
| return "constant[" + value + "]"; |
| } |
| |
| /** Truth value. */ |
| private boolean value; |
| } |