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SUMMARY: NESTED | FIELD | CONSTR | METHOD DETAIL: FIELD | CONSTR | METHOD |
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FlexDoc/Javadoc 2.0 Demo Java Doc |
Class Package
java.lang.Package
All Implemented Interfaces:
public class Package
Represents metadata about a run-time package associated with a class loader.
Metadata includes annotations, versioning, and sealing.
Annotations for the run-time package are read from package-info.class
at the same code source as classes in the run-time package.
The set of classes that make up the run-time package may implement a
particular specification. The specification title, version, and vendor
(indicating the owner/maintainer of the specification) can be provided
when the Package is defined. An application can ask if the
Package is compatible with a particular specification version
by using the Package.isCompatibleWith(String)
method. In addition, information about the actual classes that make up the
run-time package can be provided when the Package is defined.
This information consists of an implementation title, version, and vendor
(indicating the supplier of the classes).
A Package may be explicitly defined with
the ClassLoader.definePackage(String, String, String, String,
String, String, String, URL) method.
The caller supplies the specification and implementation titles, versions, and
vendors. The caller also indicates whether the package is
sealed.
If a Package is not explicitly defined for a run-time package when
a class in that run-time package is defined, then a Package is
automatically defined by the class's defining class loader, as follows.
A Package automatically defined for classes in a named module has
the following properties:
- The name of the package is derived from the binary names
of the classes. Since classes in a named module must be in a named package,
the derived name is never empty.
- The package is sealed with the module location as the code source, if known.
- The specification and implementation titles, versions, and vendors
are unspecified.
- Any annotations on the package are read from package-info.class
as specified above.
A Package automatically defined for classes in an unnamed module
has the following properties:
- The name of the package is either "" (for classes in an unnamed package)
or derived from the binary names of the classes
(for classes in a named package).
- The package is not sealed.
- The specification and implementation titles, versions, and vendors
are unspecified.
- Any annotations on the package are read from package-info.class
as specified above.
A Package can be obtained with the Package.getPackage(String) and ClassLoader.getDefinedPackage(String) methods.
Every Package defined by a class loader can be obtained
with the Package.getPackages() and
ClassLoader.getDefinedPackages() methods.
Implementation Note:
The
builtin class loaders
do not explicitly define
Package objects for packages in
named modules. Instead those packages are automatically defined
and have no specification and implementation versioning information.
Since:
1.2
See Also:
Method Summary |
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Returns this element's annotation for the specified type if
such an annotation is present, else null.
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Returns annotations that are present on this element.
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Returns annotations that are associated with this element.
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Returns this element's annotation for the specified type if
such an annotation is directly present, else null.
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Returns annotations that are directly present on this element.
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Returns this element's annotation(s) for the specified type if
such annotations are either directly present or
indirectly present.
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Return the title of this package.
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Returns the vendor that implemented this package, null
is returned if it is not known.
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Return the version of this implementation.
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Return the name of this package.
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Deprecated. If multiple class loaders delegate to each other and define classes
with the same package name, and one such loader relies on the lookup
behavior of getPackage to return a Package from
a parent loader, then the properties exposed by the Package
may not be as expected in the rest of the program.
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Returns all of the Packages defined by the caller's class loader
and its ancestors.
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Return the title of the specification that this package implements.
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Return the name of the organization, vendor,
or company that owns and maintains the specification
of the classes that implement this package.
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Returns the version number of the specification
that this package implements.
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int |
Return the hash code computed from the package name.
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boolean |
Returns true if an annotation for the specified type
is present on this element, else false.
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boolean |
Compare this package's specification version with a
desired version.
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boolean |
Returns true if this package is sealed.
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boolean |
Returns true if this package is sealed with respect to the specified
code source url.
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Returns the string representation of this Package.
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Methods inherited from class java.lang. Object |
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Return the name of this package.
Returns:
The fully-qualified name of this package as defined in section {@jls 6.5.3} of
The Java Language Specification,
for example, java.lang
public String getSpecificationTitle |
() |
Return the title of the specification that this package implements.
Returns:
the specification title, null is returned if it is not known.
public String getSpecificationVersion |
() |
Returns the version number of the specification
that this package implements.
This version string must be a sequence of non-negative decimal
integers separated by "."'s and may have leading zeros.
When version strings are compared the most significant
numbers are compared.
Specification version numbers use a syntax that consists of non-negative
decimal integers separated by periods ".", for example "2.0" or
"1.2.3.4.5.6.7". This allows an extensible number to be used to represent
major, minor, micro, etc. versions. The version specification is described
by the following formal grammar:
- SpecificationVersion:
- Digits RefinedVersionopt
- RefinedVersion:
- . Digits
- . Digits RefinedVersion
- Digits:
- Digit
- Digits
- Digit:
- any character for which Character.isDigit(char) returns true,
e.g. 0, 1, 2, ...
Returns:
the specification version, null is returned if it is not known.
public String getSpecificationVendor |
() |
Return the name of the organization, vendor,
or company that owns and maintains the specification
of the classes that implement this package.
Returns:
the specification vendor, null is returned if it is not known.
public String getImplementationTitle |
() |
Return the title of this package.
Returns:
the title of the implementation, null is returned if it is not known.
public String getImplementationVersion |
() |
Return the version of this implementation. It consists of any string
assigned by the vendor of this implementation and does
not have any particular syntax specified or expected by the Java
runtime. It may be compared for equality with other
package version strings used for this implementation
by this vendor for this package.
Returns:
the version of the implementation, null is returned if it is not known.
public String getImplementationVendor |
() |
Returns the vendor that implemented this package,
null
is returned if it is not known.
Returns:
the vendor that implemented this package, null
is returned if it is not known.
public boolean isSealed |
() |
Returns true if this package is sealed.
Returns:
true if the package is sealed, false otherwise
Returns true if this package is sealed with respect to the specified
code source
url.
Parameters:
url - the code source URL
Returns:
true if this package is sealed with respect to the given url
public boolean isCompatibleWith |
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throws |
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Compare this package's specification version with a
desired version. It returns true if
this packages specification version number is greater than or equal
to the desired version number.
Version numbers are compared by sequentially comparing corresponding
components of the desired and specification strings.
Each component is converted as a decimal integer and the values
compared.
If the specification value is greater than the desired
value true is returned. If the value is less false is returned.
If the values are equal the period is skipped and the next pair of
components is compared.
Parameters:
desired - the version string of the desired version.
Returns:
true if this package's version number is greater
than or equal to the desired version number
Throws:
NumberFormatException - if the current version is not known or
the desired or current version is not of the correct dotted form.
Deprecated. If multiple class loaders delegate to each other and define classes
with the same package name, and one such loader relies on the lookup
behavior of getPackage to return a Package from
a parent loader, then the properties exposed by the Package
may not be as expected in the rest of the program.
For example, the Package will only expose annotations from the
package-info.class file defined by the parent loader, even if
annotations exist in a package-info.class file defined by
a child loader. A more robust approach is to use the
ClassLoader.getDefinedPackage(String) method which returns
a Package for the specified class loader.
Finds a package by name in the caller's class loader and its
ancestors.
If the caller's class loader defines a Package of the given name,
the Package is returned. Otherwise, the ancestors of the
caller's class loader are searched recursively (parent by parent)
for a Package of the given name.
Calling this method is equivalent to calling ClassLoader.getPackage(String)
on a ClassLoader instance which is the caller's class loader.
Parameters:
name - A package name, such as "java.lang".
Returns:
The Package of the given name defined by the caller's
class loader or its ancestors, or null if not found.
Throws:
See Also:
public static Package[] getPackages |
() |
Returns all of the
Packages defined by the caller's class loader
and its ancestors. The returned array may contain more than one
Package object of the same package name, each defined by
a different class loader in the class loader hierarchy.
Calling this method is equivalent to calling ClassLoader.getPackages()
on a ClassLoader instance which is the caller's class loader.
Returns:
The array of Package objects defined by this
class loader and its ancestors
See Also:
Return the hash code computed from the package name.
Overrides:
Returns:
the hash code computed from the package name.
See Also:
Returns the string representation of this Package.
Its value is the string "package " and the package name.
If the package title is defined it is appended.
If the package version is defined it is appended.
Overrides:
Returns:
the string representation of the package.
Returns this element's annotation for the specified type if
such an annotation is
present, else null.
Note that any annotation returned by this method is a
declaration annotation.
Specified by:
Type Parameters:
A - the type of the annotation to query for and return if present
Parameters:
annotationClass - the Class object corresponding to the
annotation type
Returns:
this element's annotation for the specified annotation type if
present on this element, else null
Throws:
Since:
1.5
public boolean isAnnotationPresent |
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Returns true if an annotation for the specified type
is
present on this element, else false. This method
is designed primarily for convenient access to marker annotations.
The truth value returned by this method is equivalent to:
getAnnotation(annotationClass) != null
Specified by:
Parameters:
annotationClass - the Class object corresponding to the
annotation type
Returns:
true if an annotation for the specified annotation
type is present on this element, else false
Throws:
Since:
1.5
Returns annotations that are
associated with this element.
If there are no annotations
associated with this element, the return
value is an array of length 0.
The difference between this method and
AnnotatedElement.getAnnotation(Class)
is that this method detects if its argument is a
repeatable
annotation type (JLS {@jls 9.6}), and if so, attempts to find one or
more annotations of that type by "looking through" a container
annotation.
The caller of this method is free to modify the returned array; it will
have no effect on the arrays returned to other callers.
Note that any annotations returned by this method are
declaration annotations.
Specified by:
Type Parameters:
A - the type of the annotation to query for and return if present
Parameters:
annotationClass - the Class object corresponding to the
annotation type
Returns:
all this element's annotations for the specified annotation type if
associated with this element, else an array of length zero
Throws:
Since:
1.8
Returns annotations that are
present on this element.
If there are no annotations
present on this element, the return
value is an array of length 0.
The caller of this method is free to modify the returned array; it will
have no effect on the arrays returned to other callers.
Note that any annotations returned by this method are
declaration annotations.
Specified by:
Returns:
annotations present on this element
Since:
1.5
Returns this element's annotation for the specified type if
such an annotation is
directly present, else null.
This method ignores inherited annotations. (Returns null if no
annotations are directly present on this element.)
Note that any annotation returned by this method is a
declaration annotation.
Specified by:
Type Parameters:
A - the type of the annotation to query for and return if directly present
Parameters:
annotationClass - the Class object corresponding to the
annotation type
Returns:
this element's annotation for the specified annotation type if
directly present on this element, else null
Throws:
Since:
1.8
getDeclaredAnnotationsByType
public < A extends Annotation> A[] getDeclaredAnnotationsByType |
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Returns this element's annotation(s) for the specified type if
such annotations are either
directly present or
indirectly present. This method ignores inherited
annotations.
If there are no specified annotations directly or indirectly
present on this element, the return value is an array of length
0.
The difference between this method and
AnnotatedElement.getDeclaredAnnotation(Class) is that this method detects if its
argument is a
repeatable annotation type (JLS {@jls 9.6}), and if so,
attempts to find one or more annotations of that type by "looking
through" a container annotation if one is present.
The caller of this method is free to modify the returned array; it will
have no effect on the arrays returned to other callers.
Specified by:
Type Parameters:
A - the type of the annotation to query for and return
if directly or indirectly present
Parameters:
annotationClass - the Class object corresponding to the
annotation type
Returns:
all this element's annotations for the specified annotation type if
directly or indirectly present on this element, else an array of length zero
Throws:
Since:
1.8
Returns annotations that are
directly present on this element.
This method ignores inherited annotations.
If there are no annotations
directly present on this element,
the return value is an array of length 0.
The caller of this method is free to modify the returned array; it will
have no effect on the arrays returned to other callers.
Note that any annotations returned by this method are
declaration annotations.
Specified by:
Returns:
annotations directly present on this element
Since:
1.5
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SUMMARY: NESTED | FIELD | CONSTR | METHOD DETAIL: FIELD | CONSTR | METHOD |
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FlexDoc/Javadoc 2.0 Demo Java Doc |
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