1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * 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.pool2;
18
19 import java.util.Objects;
20
21 /**
22 * A base implementation of {@code KeyedPooledObjectFactory}.
23 * <p>
24 * All operations defined here are essentially no-op's.
25 * </p>
26 * <p>
27 * This class is immutable, and therefore thread-safe.
28 * </p>
29 *
30 * @see KeyedPooledObjectFactory
31 *
32 * @param <K> The type of keys managed by this factory.
33 * @param <V> Type of element managed by this factory.
34 *
35 * @since 2.0
36 */
37 public abstract class BaseKeyedPooledObjectFactory<K, V> extends BaseObject implements KeyedPooledObjectFactory<K, V> {
38
39 /**
40 * Reinitializes an instance to be returned by the pool.
41 * <p>
42 * The default implementation is a no-op.
43 * </p>
44 *
45 * @param key the key used when selecting the object
46 * @param p a {@code PooledObject} wrapping the instance to be activated
47 */
48 @Override
49 public void activateObject(final K key, final PooledObject<V> p) throws Exception {
50 // The default implementation is a no-op.
51 }
52
53 /**
54 * Creates an instance that can be served by the pool.
55 *
56 * @param key the key used when constructing the object
57 * @return an instance that can be served by the pool
58 *
59 * @throws Exception if there is a problem creating a new instance,
60 * this will be propagated to the code requesting an object.
61 */
62 public abstract V create(K key) throws Exception;
63
64 /**
65 * Destroys an instance no longer needed by the pool.
66 * <p>
67 * The default implementation is a no-op.
68 * </p>
69 *
70 * @param key the key used when selecting the instance
71 * @param p a {@code PooledObject} wrapping the instance to be destroyed
72 */
73 @Override
74 public void destroyObject(final K key, final PooledObject<V> p) throws Exception {
75 // The default implementation is a no-op.
76 }
77
78 @Override
79 public PooledObject<V> makeObject(final K key) throws Exception {
80 return wrap(
81 Objects.requireNonNull(create(key), () -> String.format("BaseKeyedPooledObjectFactory(%s).create(key=%s) = null", getClass().getName(), key)));
82 }
83
84 /**
85 * Uninitializes an instance to be returned to the idle object pool.
86 * <p>
87 * The default implementation is a no-op.
88 * </p>
89 *
90 * @param key the key used when selecting the object
91 * @param p a {@code PooledObject} wrapping the instance to be passivated
92 */
93 @Override
94 public void passivateObject(final K key, final PooledObject<V> p) throws Exception {
95 // The default implementation is a no-op.
96 }
97
98 /**
99 * Ensures that the instance is safe to be returned by the pool.
100 * <p>
101 * The default implementation always returns {@code true}.
102 * </p>
103 *
104 * @param key the key used when selecting the object
105 * @param p a {@code PooledObject} wrapping the instance to be validated
106 * @return always {@code true} in this default implementation
107 */
108 @Override
109 public boolean validateObject(final K key, final PooledObject<V> p) {
110 return true;
111 }
112
113 /**
114 * Wraps the provided instance with an implementation of
115 * {@link PooledObject}.
116 *
117 * @param value the instance to wrap, should not be null.
118 * @return The provided instance, wrapped by a {@link PooledObject}
119 */
120 public abstract PooledObject<V> wrap(V value);
121 }