src-spring-framework

13156 Commits

19 Branches

274 Tags

318 MiB

Tree: 5202250179

Commit Graph

Author	SHA1	Message	Date
Stephane Nicoll	dcade06fa0	Support for candidate components index This commit adds a "spring-context-indexer" module that can be added to any project in order to generate an index of candidate components defined in the project. `CandidateComponentsIndexer` is a standard annotation processor that looks for source files with target annotations (typically `@Component`) and references them in a `META-INF/spring.components` generated file. Each entry in the index is the fully qualified name of a candidate component and the comma-separated list of stereotypes that apply to that candidate. A typical example of a stereotype is `@Component`. If a project has a `com.example.FooService` annotated with `@Component` the following `META-INF/spring.components` file is generated at compile time: ``` com.example.FooService=org.springframework.stereotype.Component ``` A new `@Indexed` annotation can be added on any annotation to instructs the scanner to include a source file that contains that annotation. For instance, `@Component` is meta-annotated with `@Indexed` now and adding `@Indexed` to more annotation types will transparently improve the index with additional information. This also works for interaces or parent classes: adding `@Indexed` on a `Repository` base interface means that the indexed can be queried for its implementation by using the fully qualified name of the `Repository` interface. The indexer also adds any class or interface that has a type-level annotation from the `javax` package. This includes obviously JPA (`@Entity` and related) but also CDI (`@Named`, `@ManagedBean`) and servlet annotations (i.e. `@WebFilter`). These are meant to handle cases where a component needs to identify candidates and use classpath scanning currently. If a `package-info.java` file exists, the package is registered using a "package-info" stereotype. Such files can later be reused by the `ApplicationContext` to avoid using component scan. A global `CandidateComponentsIndex` can be easily loaded from the current classpath using `CandidateComponentsIndexLoader`. The core framework uses such infrastructure in two areas: to retrieve the candidate `@Component`s and to build a default `PersistenceUnitInfo`. Rather than scanning the classpath and using ASM to identify candidates, the index is used if present. As long as the include filters refer to an annotation that is directly annotated with `@Indexed` or an assignable type that is directly annotated with `@Indexed`, the index can be used since a dedicated entry wil be present for that type. If any other unsupported include filter is specified, we fallback on classpath scanning. In case the index is incomplete or cannot be used, The `spring.index.ignore` system property can be set to `true` or, alternatively, in a "spring.properties" at the root of the classpath. Issue: SPR-11890	9 years ago

Author

SHA1

Message

Date

Stephane Nicoll

dcade06fa0

Support for candidate components index

This commit adds a "spring-context-indexer" module that can be added to
any project in order to generate an index of candidate components defined
in the project.

`CandidateComponentsIndexer` is a standard annotation processor that
looks for source files with target annotations (typically `@Component`)
and references them in a `META-INF/spring.components` generated file.

Each entry in the index is the fully qualified name of a candidate
component and the comma-separated list of stereotypes that apply to that
candidate. A typical example of a stereotype is `@Component`. If a
project has a `com.example.FooService` annotated with `@Component` the
following `META-INF/spring.components` file is generated at compile time:

```
com.example.FooService=org.springframework.stereotype.Component
```

A new `@Indexed` annotation can be added on any annotation to instructs
the scanner to include a source file that contains that annotation. For
instance, `@Component` is meta-annotated with `@Indexed` now and adding
`@Indexed` to more annotation types will transparently improve the index
with additional information. This also works for interaces or parent
classes: adding `@Indexed` on a `Repository` base interface means that
the indexed can be queried for its implementation by using the fully
qualified name of the `Repository` interface.

The indexer also adds any class or interface that has a type-level
annotation from the `javax` package. This includes obviously JPA
(`@Entity` and related) but also CDI (`@Named`, `@ManagedBean`) and
servlet annotations (i.e. `@WebFilter`). These are meant to handle
cases where a component needs to identify candidates and use classpath
scanning currently.

If a `package-info.java` file exists, the package is registered using
a "package-info" stereotype.

Such files can later be reused by the `ApplicationContext` to avoid
using component scan. A global `CandidateComponentsIndex` can be easily
loaded from the current classpath using `CandidateComponentsIndexLoader`.

The core framework uses such infrastructure in two areas: to retrieve
the candidate `@Component`s and to build a default `PersistenceUnitInfo`.
Rather than scanning the classpath and using ASM to identify candidates,
the index is used if present.

As long as the include filters refer to an annotation that is directly
annotated with `@Indexed` or an assignable type that is directly
annotated with `@Indexed`, the index can be used since a dedicated entry
wil be present for that type. If any other unsupported include filter is
specified, we fallback on classpath scanning.

In case the index is incomplete or cannot be used, The
`spring.index.ignore` system property can be set to `true` or,
alternatively, in a "spring.properties" at the root of the classpath.

Issue: SPR-11890

9 years ago

1 Commits (5202250179caf4703943726358583835b152ab9c)