01: /**
02: *
03: * Licensed to the Apache Software Foundation (ASF) under one or more
04: * contributor license agreements. See the NOTICE file distributed with
05: * this work for additional information regarding copyright ownership.
06: * The ASF licenses this file to You under the Apache License, Version 2.0
07: * (the "License"); you may not use this file except in compliance with
08: * the License. You may obtain a copy of the License at
09: *
10: * http://www.apache.org/licenses/LICENSE-2.0
11: *
12: * Unless required by applicable law or agreed to in writing, software
13: * distributed under the License is distributed on an "AS IS" BASIS,
14: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15: * See the License for the specific language governing permissions and
16: * limitations under the License.
17: */package org.apache.openejb.jee;
18:
19: /**
20: * Extracts an immutable key for this object.
21: *
22: * It is important for the key to not be mutable and that the key value
23: * itself is not changed in the object. If this happens any AutoIndex,
24: * or Map using this key will break.
25: */
26: public interface KeyExtractor<K, V> {
27: /**
28: * Gets the immutable key for the specified value.
29: * @return gets the immutable key for the specified value
30: */
31: K getKey(V value);
32: }
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