1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.maven.di;
20
21 import java.util.function.Supplier;
22
23 import org.apache.maven.api.annotations.Experimental;
24 import org.apache.maven.api.annotations.Nonnull;
25
26 /**
27 * A {@code Scope} defines how visible instances are when managed by a {@link org.apache.maven.di.Injector}.
28 * Typically, instances are created with <i>no scope</i>, meaning they don’t retain any state from the
29 * framework’s perspective: the {@code Injector} generates the instance, injects it into the necessary class,
30 * and then immediately forgets it. By linking a scope to a specific binding, the created instance can be
31 * “remembered” and reused for future injections.
32 * <p>
33 * Instances are associated to a given scope by means of a {@link org.apache.maven.api.di.Scope @Scope}
34 * annotation, usually put on another annotation. For example, the {@code @Singleton} annotation is used
35 * to indicate that a given binding should be scoped as a singleton.
36 * <p>
37 * The following scopes are currently supported:
38 * <ul>
39 * <li>{@link org.apache.maven.api.di.Singleton @Singleton}</li>
40 * <li>{@link org.apache.maven.api.di.SessionScoped @SessionScoped}</li>
41 * <li>{@link org.apache.maven.api.di.MojoExecutionScoped @MojoExecutionScoped}</li>
42 * </ul>
43 *
44 * @since 4.0.0
45 */
46 @Experimental
47 public interface Scope {
48
49 @Nonnull
50 <T> Supplier<T> scope(@Nonnull Key<T> key, @Nonnull Supplier<T> unscoped);
51 }