diff options
Diffstat (limited to 'jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/iterators/FilteringIterator.java')
-rw-r--r-- | jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/iterators/FilteringIterator.java | 135 |
1 files changed, 0 insertions, 135 deletions
diff --git a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/iterators/FilteringIterator.java b/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/iterators/FilteringIterator.java deleted file mode 100644 index dd8230bf26..0000000000 --- a/jpa/plugins/org.eclipse.jpt.utility/src/org/eclipse/jpt/utility/internal/iterators/FilteringIterator.java +++ /dev/null @@ -1,135 +0,0 @@ -/******************************************************************************* - * Copyright (c) 2005, 2008 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.Filter; -import org.eclipse.jpt.utility.internal.StringTools; - -/** - * A <code>FilteringIterator</code> wraps another <code>Iterator</code> - * and uses a <code>Filter</code> to determine which elements in the - * nested iterator are to be returned by calls to <code>next()</code>. - * <p> - * As an alternative to building a <code>Filter</code>, a subclass - * of <code>FilteringIterator</code> can override the - * <code>accept(Object)</code> method. - * <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 filtered iterator's <code>next()</code> - * method is invoked. This is because the "next" element must be - * checked for whether it is to be accepted before the filtered iterator - * can determine whether it has a "next" element (i.e. that the - * <code>hasNext()</code> method should return <code>true</code>). - * This also prevents a filtered iterator from supporting the optional - * <code>remove()</code> method. - */ -public class FilteringIterator<E1, E2> - implements Iterator<E2> -{ - private final Iterator<? extends E1> nestedIterator; - private final Filter<E1> filter; - private E2 next; - private boolean done; - - - /** - * Construct an iterator with the specified nested - * iterator and a disabled filter. - * Use this constructor if you want to override the - * <code>accept(Object)</code> method instead of building - * a <code>Filter</code>. - */ - public FilteringIterator(Iterator<? extends E1> nestedIterator) { - this(nestedIterator, Filter.Disabled.<E1>instance()); - } - - /** - * Construct an iterator with the specified nested - * iterator and filter. - */ - public FilteringIterator(Iterator<? extends E1> nestedIterator, Filter<E1> filter) { - super(); - this.nestedIterator = nestedIterator; - this.filter = filter; - this.loadNext(); - } - - public boolean hasNext() { - return ! this.done; - } - - public E2 next() { - if (this.done) { - throw new NoSuchElementException(); - } - E2 result = this.next; - this.loadNext(); - return result; - } - - /** - * 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 valid entry from the nested - * iterator. If there are none, next is set to <code>END</code>. - */ - private void loadNext() { - this.done = true; - while (this.nestedIterator.hasNext() && (this.done)) { - E1 temp = this.nestedIterator.next(); - if (this.accept(temp)) { - // assume that if the object was accepted it is of type E - this.next = this.cast(temp); - this.done = false; - } else { - this.next = null; - this.done = true; - } - } - } - - /** - * We have to assume the filter will only "accept" objects that can - * be cast to E2. - */ - @SuppressWarnings("unchecked") - private E2 cast(E1 o) { - return (E2) o; - } - - /** - * Return whether the <code>FilteringIterator</code> - * should return the specified next element from a call to the - * <code>next()</code> method. - * <p> - * This method can be overridden by a subclass as an - * alternative to building a <code>Filter</code>. - */ - protected boolean accept(E1 o) { - return this.filter.accept(o); - } - - @Override - public String toString() { - return StringTools.buildToStringFor(this, this.nestedIterator); - } - -} |