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| injector [2024/10/21 11:59] – created datafox | injector [2024/11/05 09:03] (current) – datafox |
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| Injector is a dependency injector. It scans the classpath for all classes, fields and methods with specific annotations and instantiates/invokes them automatically, resolving and injecting dependencies as it does. From version 2.0.0 onwards type parameters are supported as well. | Injector is a dependency injector. It scans the classpath for all classes, fields and methods with specific annotations and instantiates/invokes them automatically, resolving and injecting dependencies as it does. From version 2.0.0 onwards type parameters are supported as well. |
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| | ===== Important ===== |
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| | Before building the injector with ''InjectorBuilder.build()'', you must first call one of the scan methods. The ''InjectorBuilder.scan()'' method is recommended for most use cases, but if you need specific scan parameters or if your environment (Android, GraalVM) requires build time scanning, you can use ''InjectorBuilder.load(ClassHierarchy)''. ''ClassHierarchy'' is a class serializable by any serializer that supports serializing ''Class<T>'' objects, and the scanner makes sure to only include classes that can be retrieved with ''Class.forName(String)''. You can generate it with the ''scan()'' methods in ''ClassScanner''. |
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| ===== Dependencies ===== | ===== Dependencies ===== |
| The ''@Component'' annotation can be used for both classes and methods. | The ''@Component'' annotation can be used for both classes and methods. |
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| A component class will be instantiated with a specific constructor (see [[#inject|''@Inject'']]), and a component method will be invoked. In both cases, all parameters of the constructor/method will be treated as dependencies. If a component method is not static, its declaring class will be treated as if it was also annotated as a component and will be subject to all the same rules. | A component class will be instantiated with a specific constructor (see ''[[#inject|@Inject]])'', and a component method will be invoked. In both cases, all parameters of the constructor/method will be treated as dependencies. If a component method is not static, its declaring class will be treated as if it was also annotated as a component and will be subject to all the same rules. |
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| If a method annotated as component is ''void'', the method will be treated as a special void component. Void components are invoked once after everything else is invoked, including methods annotated with ''@Initialize''. This is useful when you need to validate other components in ways that are not covered by the Injector itself. | If a method annotated as component is ''void'', the method will be treated as a special void component. Void components are invoked once after everything else is invoked, including methods annotated with ''@Initialize''. This is useful when you need to validate other components in ways that are not covered by the Injector itself. |
