diff options
Diffstat (limited to 'jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/iterators/PeekableIterator.java')
-rw-r--r-- | jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/iterators/PeekableIterator.java | 100 |
1 files changed, 0 insertions, 100 deletions
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/iterators/PeekableIterator.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/iterators/PeekableIterator.java deleted file mode 100644 index 316aedcf63..0000000000 --- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/iterators/PeekableIterator.java +++ /dev/null @@ -1,100 +0,0 @@ -/******************************************************************************* - * Copyright (c) 2005, 2007 Oracle. All rights reserved. - * This program and the accompanying materials are made available under the - * terms of the Eclipse Public License v1.0, which accompanies this distribution - * and is available at http://www.eclipse.org/legal/epl-v10.html. - * - * Contributors: - * Oracle - initial API and implementation - ******************************************************************************/ -package org.eclipse.jpt.utility.internal.iterators; - -import java.util.Iterator; -import java.util.NoSuchElementException; -import org.eclipse.jpt.utility.internal.StringTools; - -/** - * A <code>PeekableIterator</code> wraps another <code>Iterator</code> - * and allows a <code>peek()</code> at the next element to be - * returned by <code>next()</code>. - * <p> - * One, possibly undesirable, side-effect of using this iterator is that - * the nested iterator's <code>next()</code> method will be invoked - * <em>before</em> the peekable iterator's <code>next()</code> - * method is invoked. This is because the "next" element must be - * pre-loaded for the <code>peek()</code> method. - * This also prevents a peekable iterator from supporting the optional - * <code>remove()</code> method. - */ - -public class PeekableIterator<E> - implements Iterator<E> -{ - private final Iterator<? extends E> nestedIterator; - private E next; - private boolean done; - - - /** - * Construct a peekable iterator that wraps the specified nested - * iterator. - */ - public PeekableIterator(Iterator<? extends E> nestedIterator) { - super(); - this.nestedIterator = nestedIterator; - this.done = false; - this.loadNext(); - } - - public boolean hasNext() { - return ! this.done; - } - - public E next() { - if (this.done) { - throw new NoSuchElementException(); - } - E result = this.next; - this.loadNext(); - return result; - } - - /** - * Return the element that will be returned by the next call to the - * <code>next()</code> method, without advancing past it. - */ - public E peek() { - if (this.done) { - throw new NoSuchElementException(); - } - return this.next; - } - - /** - * Because we need to pre-load the next element - * to be returned, we cannot support the <code>remove()</code> - * method. - */ - public void remove() { - throw new UnsupportedOperationException(); - } - - /** - * Load next with the next entry from the nested - * iterator. If there are none, next is set to <code>END</code>. - */ - private void loadNext() { - if (this.nestedIterator.hasNext()) { - this.next = this.nestedIterator.next(); - } else { - this.next = null; - this.done = true; - } - } - - @Override - public String toString() { - return StringTools.buildToStringFor(this, this.nestedIterator); - } - -} |