| /* |
| |
| Derby - Class org.apache.derby.iapi.types.Orderable |
| |
| 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.derby.iapi.types; |
| |
| import org.apache.derby.iapi.error.StandardException; |
| |
| /** |
| |
| The Orderable interface represents a value that can |
| be linearly ordered. |
| <P> |
| Currently only supports linear (<, =, <=) operations. |
| Eventually we may want to do other types of orderings, |
| in which case there would probably be a number of interfaces |
| for each "class" of ordering. |
| <P> |
| The implementation must handle the comparison of null |
| values. This may require some changes to the interface, |
| since (at least in some contexts) comparing a value with |
| null should return unknown instead of true or false. |
| |
| **/ |
| |
| public interface Orderable |
| { |
| |
| /** Ordering operation constant representing '<' **/ |
| static final int ORDER_OP_LESSTHAN = 1; |
| /** Ordering operation constant representing '=' **/ |
| static final int ORDER_OP_EQUALS = 2; |
| /** Ordering operation constant representing '<=' **/ |
| static final int ORDER_OP_LESSOREQUALS = 3; |
| |
| /** |
| * These 2 ordering operations are used by the language layer |
| * when flipping the operation due to type precedence rules. |
| * (For example, 1 < 1.1 -> 1.1 > 1) |
| */ |
| /** Ordering operation constant representing '>' **/ |
| static final int ORDER_OP_GREATERTHAN = 4; |
| /** Ordering operation constant representing '>=' **/ |
| static final int ORDER_OP_GREATEROREQUALS = 5; |
| |
| |
| } |