Named oliver.twist has no better access to the Package having a subpackage with the same simple name as a top levelįor example, there is no special access relationshipīetween a package named oliver and another packageĪnd evelyn.waugh. Hierarchical naming structure for packages is intended to beĬonvenient for organizing related packages in a conventional manner,īut has no significance in itself other than the prohibition against a Because the package vector contains aĬlass named Vector, it cannot also have a Types are different, reflected by the fact that they have differentįully qualified names ( §6.7). Named Vector, even though the package java.utilĪlso declares a class named Vector. It is however possible for members of different Happened to pick the same package name and these packages were later The conflicts that would otherwise occur if two development groups Package names should be chosen using qualified names. Have a simple name, but if code is to be widely distributed, unique Package is accessible only to code inside the module.ĭevelopment, a package can be unnamed ( §7.4.2) or Type that is declared public but is not a member of an exported The type is declared public and is a member of an exported package. Level type is accessible outside the module that declares it only if Package that declares it only if the type is declared public. Package and also automatically imports all of the public typesĭeclared in the predefined package java.lang.Ī top level type is accessible ( §6.6) outside the Modules and packages that are stored in aįile system may have certain constraints on the organization of theirĬompilation units to allow a simple implementation to find module andĬompilation unit automatically has access to all types declared in its Modules and packages may be stored in a file system or in a database Packages (by specifying which of its packages are exported). Specifying dependences) and controls how other modules use its Thus, a module controls how its packages use other modules (by Module, then the first module must explicitly depend on the second Furthermore, ifĬode in a module wishes to access the packages exported by another Then only code inside the module may access its types. If a package is not exported by a module, Packages as exported, which means their types may be accessed fromĬode outside the module. If a set of packages is sufficiently cohesive, then the packages mayīe grouped into a module. May contain compilation units and subpackages of their own.Įach package has its own set of names for types, which helps to ( §7.1) are class and interface types, which areĭeclared in compilation units of the package, and subpackages, which Programs are organized as sets of packages. Static-Import-on-Demand Declarations 7.6. Type-Import-on-Demand Declarations 7.5.3. Package Observability and Visibility 7.5. Host Support for Modules and Packages 7.3. For example, URLClassLoader would not be implementable for 'http:' URLs because the HTTP protocol does not provide a standard way to retrieve the entries in a directory.īesides, there are few situations where a production application really needs to reflectively find all classes in a package.Table of Contents 7.1. If the classloader API did include a method to give all classes in a package, it would limit the schemes that can be used for classloading. I understand that the omission is deliberate. It seems this is a massive fault in the java reflection API I would recommend that you find an alternative approach to the problem you are tying to address. One problem is that the ClassLoader API does not support iterating over all of the classes / packages that it could load. Then you use Class.forName() load the corresponding classes (trying to avoid initializing them), and use clazz.isAssignableFrom(subclazz) to see which of them are subclasses.īut this won't work in all cases. Basically, you need to map the package name to a pathname and use the File and/or ZipFile APIs to look for files in the relevant "directory" whose name ends with ".class". if your application's classes are loaded from local directories or JAR files. It is possible to do (messily) in some cases e.g.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |