01: /*
02: * Licensed to the Apache Software Foundation (ASF) under one or more
03: * contributor license agreements. See the NOTICE file distributed with
04: * this work for additional information regarding copyright ownership.
05: * The ASF licenses this file to You under the Apache License, Version 2.0
06: * (the "License"); you may not use this file except in compliance with
07: * the License. You may obtain a copy of the License at
08: *
09: * http://www.apache.org/licenses/LICENSE-2.0
10: *
11: * Unless required by applicable law or agreed to in writing, software
12: * distributed under the License is distributed on an "AS IS" BASIS,
13: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14: * See the License for the specific language governing permissions and
15: * limitations under the License.
16: */
17: package org.apache.commons.collections;
18:
19: import java.util.Collection;
20:
21: /**
22: * Defines a collection that allows objects to be removed in some well-defined order.
23: * <p>
24: * The removal order can be based on insertion order (eg, a FIFO queue or a
25: * LIFO stack), on access order (eg, an LRU cache), on some arbitrary comparator
26: * (eg, a priority queue) or on any other well-defined ordering.
27: * <p>
28: * Note that the removal order is not necessarily the same as the iteration
29: * order. A <code>Buffer</code> implementation may have equivalent removal
30: * and iteration orders, but this is not required.
31: * <p>
32: * This interface does not specify any behavior for
33: * {@link Object#equals(Object)} and {@link Object#hashCode} methods. It
34: * is therefore possible for a <code>Buffer</code> implementation to also
35: * also implement {@link java.util.List}, {@link java.util.Set} or
36: * {@link Bag}.
37: * <p>
38: * <strong>Note:</strong> this class should be bytecode-identical to the
39: * version in commons collections. This is required to allow backwards
40: * compability with both previous versions of BeanUtils and also allow
41: * coexistance with both collections 2.1 and 3.0.
42: *
43: * @since Commons Collections 2.1
44: * @version $Revision: 555824 $ $Date: 2007-07-13 01:27:15 +0100 (Fri, 13 Jul 2007) $
45: *
46: * @author Avalon
47: * @author Berin Loritsch
48: * @author Paul Jack
49: * @author Stephen Colebourne
50: */
51: public interface Buffer extends Collection {
52:
53: /**
54: * Gets and removes the next object from the buffer.
55: *
56: * @return the next object in the buffer, which is also removed
57: * @throws BufferUnderflowException if the buffer is already empty
58: */
59: Object remove();
60:
61: /**
62: * Gets the next object from the buffer without removing it.
63: *
64: * @return the next object in the buffer, which is not removed
65: * @throws BufferUnderflowException if the buffer is empty
66: */
67: Object get();
68:
69: }
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