01: ///////////////////////////////////////////////////////////////////////////////
02: // Copyright (c) 2001, Eric D. Friedman All Rights Reserved.
03: //
04: // This library is free software; you can redistribute it and/or
05: // modify it under the terms of the GNU Lesser General Public
06: // License as published by the Free Software Foundation; either
07: // version 2.1 of the License, or (at your option) any later version.
08: //
09: // This library is distributed in the hope that it will be useful,
10: // but WITHOUT ANY WARRANTY; without even the implied warranty of
11: // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12: // GNU General Public License for more details.
13: //
14: // You should have received a copy of the GNU Lesser General Public
15: // License along with this program; if not, write to the Free Software
16: // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17: ///////////////////////////////////////////////////////////////////////////////
18:
19: package gnu.trove;
20:
21: import java.util.ConcurrentModificationException;
22:
23: /**
24: * Implements all iterator functions for the hashed object set.
25: * Subclasses may override objectAtIndex to vary the object
26: * returned by calls to next() (e.g. for values, and Map.Entry
27: * objects).
28: *
29: * <p> Note that iteration is fastest if you forego the calls to
30: * <tt>hasNext</tt> in favor of checking the size of the structure
31: * yourself and then call next() that many times:
32: *
33: * <pre>
34: * Iterator i = collection.iterator();
35: * for (int size = collection.size(); size-- > 0;) {
36: * Object o = i.next();
37: * }
38: * </pre>
39: *
40: * <p>You may, of course, use the hasNext(), next() idiom too if
41: * you aren't in a performance critical spot.</p>
42: *
43: */
44: abstract class TPrimitiveIterator extends TIterator {
45: /** the collection on which this iterator operates. */
46: protected final TPrimitiveHash _hash;
47:
48: /**
49: * Creates a TPrimitiveIterator for the specified collection.
50: */
51: public TPrimitiveIterator(TPrimitiveHash hash) {
52: super (hash);
53: _hash = hash;
54: }
55:
56: /**
57: * Returns the index of the next value in the data structure
58: * or a negative value if the iterator is exhausted.
59: *
60: * @return an <code>int</code> value
61: * @exception ConcurrentModificationException if the underlying collection's
62: * size has been modified since the iterator was created.
63: */
64: protected final int nextIndex() {
65: if (_expectedSize != _hash.size()) {
66: throw new ConcurrentModificationException();
67: }
68:
69: byte[] states = _hash._states;
70: int i = _index;
71: while (i-- > 0 && (states[i] != TPrimitiveHash.FULL))
72: ;
73: return i;
74: }
75:
76: } // TPrimitiveIterator
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