| package org.apache.maven.surefire.api.util; |
| |
| /* |
| * 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. |
| */ |
| |
| import java.util.Iterator; |
| import java.util.NoSuchElementException; |
| |
| /** |
| * This iterator is marked as stopped if {@link #isClosed()} returns {@code true}. |
| * If the iterator has been closed before calling {@link #hasNext()} then the method returns {@code false}. |
| * If the iterator was closed after {@link #hasNext() hasNext returns true} but before {@link #next()}, the |
| * method {@link #next()} throws {@link java.util.NoSuchElementException}. |
| * The method {@link #remove()} throws {@link IllegalStateException} if the iterator has been closed. |
| * |
| * @param <T> the type of elements returned by this iterator |
| * |
| * @author <a href="mailto:tibordigana@apache.org">Tibor Digana (tibor17)</a> |
| * @since 2.19.1 |
| */ |
| public abstract class CloseableIterator<T> |
| implements Iterator<T> |
| { |
| private Boolean finishCurrentIteration; |
| |
| protected abstract boolean isClosed(); |
| protected abstract boolean doHasNext(); |
| protected abstract T doNext(); |
| protected abstract void doRemove(); |
| |
| @Override |
| public boolean hasNext() |
| { |
| popMarker(); |
| return !finishCurrentIteration && doHasNext(); |
| } |
| |
| @Override |
| public T next() |
| { |
| try |
| { |
| if ( popMarker() && finishCurrentIteration ) |
| { |
| throw new NoSuchElementException( "iterator closed" ); |
| } |
| return doNext(); |
| } |
| finally |
| { |
| finishCurrentIteration = null; |
| } |
| } |
| |
| @Override |
| public void remove() |
| { |
| try |
| { |
| if ( popMarker() && finishCurrentIteration ) |
| { |
| throw new IllegalStateException( "iterator closed" ); |
| } |
| doRemove(); |
| } |
| finally |
| { |
| finishCurrentIteration = null; |
| } |
| } |
| |
| /** |
| * @return {@code true} if marker changed from NULL to anything |
| */ |
| private boolean popMarker() |
| { |
| if ( finishCurrentIteration == null ) |
| { |
| finishCurrentIteration = isClosed(); |
| return true; |
| } |
| return false; |
| } |
| } |