com.hazelcast.org.apache.calcite.util.Stacks Maven / Gradle / Ivy
/*
* 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 com.hazelcast.org.apache.calcite.util;
import java.util.List;
/**
* Utilities to make vanilla lists look like stacks.
*/
@Deprecated // to be removed before 2.0
public class Stacks {
private Stacks() {
}
/**
* Returns the most recently added element in the stack. Throws if the
* stack is empty.
*/
public static T peek(List stack) {
return stack.get(stack.size() - 1);
}
/**
* Returns the {@code n}th most recently added element in the stack.
* Throws if the stack is empty.
*/
public static T peek(int n, List stack) {
return stack.get(stack.size() - n - 1);
}
/**
* Adds an element to the stack.
*/
public static void push(List stack, T element) {
stack.add(element);
}
/**
* Removes an element from the stack. Asserts of the element is not the
* one last added; throws if the stack is empty.
*/
public static void pop(List stack, T element) {
assert stack.get(stack.size() - 1) == element;
stack.remove(stack.size() - 1);
}
/**
* Removes an element from the stack and returns it.
*
* Throws if the stack is empty.
*/
public static T pop(List stack) {
return stack.remove(stack.size() - 1);
}
}