/*
* 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 jakarta.el.ELException;
import jakarta.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;
}
}
}