| /* |
| * 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.el.stream; |
| |
| import javax.el.ELException; |
| import javax.el.LambdaExpression; |
| |
| import org.apache.el.util.MessageFactory; |
| |
| public class Optional { |
| |
| private final Object obj; |
| |
| static final Optional EMPTY = new Optional(null); |
| |
| Optional(Object obj) { |
| this.obj = obj; |
| } |
| |
| |
| public Object get() throws ELException { |
| if (obj == null) { |
| throw new ELException(MessageFactory.get("stream.optional.empty")); |
| } else { |
| return obj; |
| } |
| } |
| |
| |
| public void ifPresent(LambdaExpression le) { |
| if (obj != null) { |
| le.invoke(obj); |
| } |
| } |
| |
| |
| public Object orElse(Object other) { |
| if (obj == null) { |
| return other; |
| } else { |
| return obj; |
| } |
| } |
| |
| |
| public Object orElseGet(Object le) { |
| if (obj == null) { |
| // EL 3.0 specification says parameter is LambdaExpression but it |
| // may already have been evaluated. If that is the case, the |
| // original parameter will have been checked to ensure it was a |
| // LambdaExpression before it was evaluated. |
| |
| if (le instanceof LambdaExpression) { |
| return ((LambdaExpression) le).invoke((Object[]) null); |
| } else { |
| return le; |
| } |
| } else { |
| return obj; |
| } |
| } |
| } |