Migrated source code from Simantics SVN

[simantics/platform.git] / bundles / org.simantics.scenegraph / src / gnu / trove / TIterator.java

diff --git a/bundles/org.simantics.scenegraph/src/gnu/trove/TIterator.java b/bundles/org.simantics.scenegraph/src/gnu/trove/TIterator.java
new file mode 100644 (file)
index 0000000..ab45f02
--- /dev/null
+++ b/bundles/org.simantics.scenegraph/src/gnu/trove/TIterator.java
@@ -0,0 +1,102 @@
+///////////////////////////////////////////////////////////////////////////////
+// Copyright (c) 2001, Eric D. Friedman All Rights Reserved.
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this program; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+///////////////////////////////////////////////////////////////////////////////
+
+package gnu.trove;
+
+import java.util.ConcurrentModificationException;
+import java.util.NoSuchElementException;
+
+/**
+ * Abstract iterator class for THash implementations.  This class provides some
+ * of the common iterator operations (hasNext(), remove()) and allows subclasses
+ * to define the mechanism(s) for advancing the iterator and returning data.
+ *
+ * @author Eric D. Friedman
+ * @version $Id: TIterator.java,v 1.3 2007/06/29 20:03:10 robeden Exp $
+ */
+abstract class TIterator {
+    /** the data structure this iterator traverses */
+    protected final THash _hash;
+    /** the number of elements this iterator believes are in the
+     * data structure it accesses. */
+    protected int _expectedSize;
+    /** the index used for iteration. */
+    protected int _index;
+
+    /**
+     *  Create an instance of TIterator over the specified THash.
+     */
+    public TIterator(THash hash) {
+        _hash = hash;
+        _expectedSize = _hash.size();
+        _index = _hash.capacity();
+    }
+
+    /**
+     * Returns true if the iterator can be advanced past its current
+     * location.
+     *
+     * @return a <code>boolean</code> value
+     */
+    public boolean hasNext() {
+        return nextIndex() >= 0;
+    }
+
+    /**
+     * Removes the last entry returned by the iterator.
+     * Invoking this method more than once for a single entry
+     * will leave the underlying data structure in a confused
+     * state.
+     */
+    public void remove() {
+        if (_expectedSize != _hash.size()) {
+            throw new ConcurrentModificationException();
+        }
+
+        // Disable auto compaction during the remove. This is a workaround for bug 1642768.
+        try {
+            _hash.tempDisableAutoCompaction();
+            _hash.removeAt(_index);
+        }
+        finally {
+            _hash.reenableAutoCompaction( false );
+        }
+
+        _expectedSize--;
+    }
+
+    /**
+     * Sets the internal <tt>index</tt> so that the `next' object
+     * can be returned.
+     */
+    protected final void moveToNextIndex() {
+        // doing the assignment && < 0 in one line shaves
+        // 3 opcodes...
+        if ((_index = nextIndex()) < 0) {
+            throw new NoSuchElementException();
+        }
+    }
+
+    /**
+     * Returns the index of the next value in the data structure
+     * or a negative value if the iterator is exhausted.
+     *
+     * @return an <code>int</code> value
+     */
+    abstract protected int nextIndex();
+} // TIterator