Package: LazySupplier

LazySupplier

name	instruction	branch	complexity	line	method
clear()	M: 0 C: 4 100%	M: 0 C: 0 100%	M: 0 C: 1 100%	M: 0 C: 2 100%	M: 0 C: 1 100%
get()	M: 0 C: 14 100%	M: 0 C: 2 100%	M: 0 C: 2 100%	M: 0 C: 4 100%	M: 0 C: 1 100%
set(Object)	M: 0 C: 4 100%	M: 0 C: 0 100%	M: 0 C: 1 100%	M: 0 C: 2 100%	M: 0 C: 1 100%
toString()	M: 0 C: 18 100%	M: 1 C: 3 75%	M: 1 C: 2 67%	M: 0 C: 1 100%	M: 0 C: 1 100%

Coverage

1: /*
2: * *************************************************************************************************************************************************************
3: *
4: * TheseFoolishThings: Miscellaneous utilities
5: * http://tidalwave.it/projects/thesefoolishthings
6: *
7: * Copyright (C) 2009 - 2024 by Tidalwave s.a.s. (http://tidalwave.it)
8: *
9: * *************************************************************************************************************************************************************
10: *
11: * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
12: * You may obtain a copy of the License at
13: *
14: * http://www.apache.org/licenses/LICENSE-2.0
15: *
16: * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
17: * CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
18: *
19: * *************************************************************************************************************************************************************
20: *
21: * git clone https://bitbucket.org/tidalwave/thesefoolishthings-src
22: * git clone https://github.com/tidalwave-it/thesefoolishthings-src
23: *
24: * *************************************************************************************************************************************************************
25: */
26: package it.tidalwave.util;
27:
28: import javax.annotation.Nonnull;
29: import javax.annotation.concurrent.ThreadSafe;
30: import java.util.function.Supplier;
31: import it.tidalwave.util.annotation.VisibleForTesting;
32: import lombok.EqualsAndHashCode;
33: import lombok.Getter;
34: import lombok.RequiredArgsConstructor;
35:
36: /***************************************************************************************************************************************************************
37: *
38: * A supplier of an object that is lazily evaluated (when its value is requested for the first time). It warranties
39: * that the real wrapped supplier is called only once.
40: *
41: * @author Fabrizio Giudici
42: * @since 3.2-ALPHA-13
43: *
44: **************************************************************************************************************************************************************/
45: @ThreadSafe @RequiredArgsConstructor(staticName = "of") @EqualsAndHashCode(of = {"ref", "initialized"})
46: public class LazySupplier<T> implements Supplier<T>
47: {
48: @Nonnull
49: private final Supplier<T> supplier;
50:
51: @VisibleForTesting volatile T ref = null;
52:
53: @Getter
54: @VisibleForTesting volatile boolean initialized;
55:
56: /** {@inheritDoc} */
57: @Override @Nonnull
58: public synchronized T get()
59: {
60: // AtomicReference.updateAndGet() not good because in case of contention it might call supplier multiple times
61: // We don't mess with double check for null since nowadays synchronized is fast
62:• if (ref == null)
63: {
64: ref = supplier.get();
65: initialized = true;
66: }
67:
68: return ref;
69: }
70:
71: public synchronized void clear()
72: {
73: ref = null;
74: }
75:
76: public void set (@Nonnull final T ref)
77: {
78: this.ref = ref;
79: }
80:
81: @Nonnull
82: public String toString()
83: {
84:• return String.format("LazySupplier(%s)", (ref == null && !initialized) ? "<not initialised>" : ref);
85: }
86: }