Class ModuleDescriptor

java.lang.Object

java.lang.module.ModuleDescriptor

All Implemented Interfaces:: Comparable<ModuleDescriptor>

public classModuleDescriptorextendsObjectimplementsComparable<ModuleDescriptor>

A module descriptor.

A module descriptor describes a named module and defines methods to obtain each of its components. The module descriptor for a named module in the Java virtual machine is obtained by invoking theModule'sgetDescriptor method. Module descriptors can also be created using theModuleDescriptor.Builder class or by reading the binary form of a module declaration (module-info.class) using theread methods defined here.

A module descriptor describes anormal, open, or automatic module.Normal modules and open modules describe theirdependences,exported-packages, the services that theyuse orprovide, and other components.Normal modules mayopen specific packages. The module descriptor for an open module does not declare any open packages (itsopens method returns an empty set) but when instantiated in the Java virtual machine then it is treated as if all packages are open. The module descriptor for an automatic module does not declare any dependences (except for the mandatory dependency on java.base), and does not declare any exported or open packages. Automatic modules receive special treatment during resolution so that they read all other modules in the configuration. When an automatic module is instantiated in the Java virtual machine then it reads every unnamed module and is treated as if all packages are exported and open.

ModuleDescriptor objects are immutable and safe for use by multiple concurrent threads.

Since:

See Also:

Module

Nested Class Summary
Nested Classes
Modifier and Type
Class
Description
static final class
ModuleDescriptor.Builder
A builder for buildingModuleDescriptor objects.
static final class
ModuleDescriptor.Exports
A package exported by a module, may be qualified or unqualified.
static enum
ModuleDescriptor.Modifier
A modifier on a module.
static final class
ModuleDescriptor.Opens
A package opened by a module, may be qualified or unqualified.
static final class
ModuleDescriptor.Provides
A service that a module provides one or more implementations of.
static final class
ModuleDescriptor.Requires
A dependence upon a module.
static final class
ModuleDescriptor.Version
A module's version string.
Method Summary
Modifier and Type
Method
Description
Set<AccessFlag>
accessFlags()
Returns the set of themodule flags.
int
compareTo(ModuleDescriptor that)
Compares this module descriptor to another.
boolean
equals(Object ob)
Tests this module descriptor for equality with the given object.
Set<ModuleDescriptor.Exports>
exports()
Returns the set ofExports objects representing the exported packages.
int
hashCode()
Computes a hash code for this module descriptor.
boolean
isAutomatic()
Returnstrue if this is an automatic module.
boolean
isOpen()
Returnstrue if this is an open module.
Optional<String>
mainClass()
Returns the module main class.
Set<ModuleDescriptor.Modifier>
modifiers()
Returns the set of module modifiers.
String
name()
Returns the module name.
staticModuleDescriptor.Builder
newAutomaticModule(String name)
Instantiates a builder to build a module descriptor for an automatic module.
staticModuleDescriptor.Builder
newModule(String name)
Instantiates a builder to build a module descriptor for anormal module.
staticModuleDescriptor.Builder
newModule(String name,Set<ModuleDescriptor.Modifier> ms)
Instantiates a builder to build a module descriptor.
staticModuleDescriptor.Builder
newOpenModule(String name)
Instantiates a builder to build a module descriptor for an open module.
Set<ModuleDescriptor.Opens>
opens()
Returns the set ofOpens objects representing the open packages.
Set<String>
packages()
Returns the set of packages in the module.
Set<ModuleDescriptor.Provides>
provides()
Returns the set ofProvides objects representing the services that the module provides.
Optional<String>
rawVersion()
Returns the string with the possibly-unparseable version of the module.
staticModuleDescriptor
read(InputStream in)
Reads the binary form of a module declaration from an input stream as a module descriptor.
staticModuleDescriptor
read(InputStream in,Supplier<Set<String>> packageFinder)
Reads the binary form of a module declaration from an input stream as a module descriptor.
staticModuleDescriptor
read(ByteBuffer bb)
Reads the binary form of a module declaration from a byte buffer as a module descriptor.
staticModuleDescriptor
read(ByteBuffer bb,Supplier<Set<String>> packageFinder)
Reads the binary form of a module declaration from a byte buffer as a module descriptor.
Set<ModuleDescriptor.Requires>
requires()
Returns the set ofRequires objects representing the module dependences.
String
toNameAndVersion()
Returns a string containing the module name and, if present, its version.
String
toString()
Returns a string describing the module.
Set<String>
uses()
Returns the set of service dependences.
Optional<ModuleDescriptor.Version>
version()
Returns the module version.
Methods declared in class java.lang.Object
clone,finalize,getClass,notify,notifyAll,wait,wait,wait

Method Details
- name
  public String name()
  Returns the module name.
  Returns:
  The module name
- modifiers
  public Set<ModuleDescriptor.Modifier> modifiers()
  Returns the set of module modifiers.
  Returns:
  A possibly-empty unmodifiable set of modifiers
- accessFlags
  public Set<AccessFlag> accessFlags()
  Returns the set of themodule flags.
  Returns:
  A possibly-empty unmodifiable set of module flags
  SeeJava Virtual Machine Specification:
  4.7.25 The Module Attribute
  Since:
  20
  See Also:
  modifiers()
- isOpen
  public boolean isOpen()
  Returnstrue if this is an open module.
  This method is equivalent to testing if the set ofmodifiers contains theOPEN modifier.
  Returns:
  true if this is an open module
- isAutomatic
  public boolean isAutomatic()
  Returnstrue if this is an automatic module.
  This method is equivalent to testing if the set ofmodifiers contains theAUTOMATIC modifier.
  Returns:
  true if this is an automatic module
- requires
  public Set<ModuleDescriptor.Requires> requires()
  Returns the set ofRequires objects representing the module dependences.
  The set includes a dependency on "java.base" when this module is not named "java.base". If this module is an automatic module then it does not have a dependency on any module other than "java.base".
  Returns:
  A possibly-empty unmodifiable set ofModuleDescriptor.Requires objects
- exports
  public Set<ModuleDescriptor.Exports> exports()
  Returns the set ofExports objects representing the exported packages.
  If this module is an automatic module then the set of exports is empty.
  Returns:
  A possibly-empty unmodifiable set of exported packages
- opens
  public Set<ModuleDescriptor.Opens> opens()
  Returns the set ofOpens objects representing the open packages.
  If this module is an open module or an automatic module then the set of open packages is empty.
  Returns:
  A possibly-empty unmodifiable set of open packages
- uses
  public Set<String> uses()
  Returns the set of service dependences.
  If this module is an automatic module then the set of service dependences is empty.
  Returns:
  A possibly-empty unmodifiable set of thebinary names of the service types used
- provides
  public Set<ModuleDescriptor.Provides> provides()
  Returns the set ofProvides objects representing the services that the module provides.
  Returns:
  The possibly-empty unmodifiable set of the services that this module provides
- version
  public Optional<ModuleDescriptor.Version> version()
  Returns the module version.
  Returns:
  This module's version, or an emptyOptional if the module does not have a version or the version isunparseable
- rawVersion
  public Optional<String> rawVersion()
  Returns the string with the possibly-unparseable version of the module.
  Returns:
  The string containing the version of the module or an emptyOptional if the module does not have a version
  See Also:
  version()
- toNameAndVersion
  public String toNameAndVersion()
  Returns a string containing the module name and, if present, its version.
  Returns:
  A string containing the module name and, if present, its version
- mainClass
  public Optional<String> mainClass()
  Returns the module main class.
  Returns:
  Thebinary name of the module's main class
- packages
  public Set<String> packages()
  Returns the set of packages in the module.
  The set of packages includes all exported and open packages, as well as the packages of any service providers, and the package for the main class.
  Returns:
  A possibly-empty unmodifiable set of the packages in the module
- compareTo
  public int compareTo(ModuleDescriptor that)
  Compares this module descriptor to another.
  TwoModuleDescriptor objects are compared by comparing their module names lexicographically. Where the module names are equal then the module versions are compared. When comparing the module versions then a module descriptor with a version is considered to succeed a module descriptor that does not have a version. If both versions areunparseable then theraw version strings are compared lexicographically. Where the module names are equal and the versions are equal (or not present in both), then the set of modifiers are compared. Sets of modifiers are compared by comparing abinary value computed for each set. If a modifier is present in the set then the bit at the position of its ordinal is1 in the binary value, otherwise0. If the two set of modifiers are also equal then the other components of the module descriptors are compared in a manner that is consistent withequals.
  Specified by:
  compareTo in interface Comparable<ModuleDescriptor>
  Parameters:
  that - The module descriptor to compare
  Returns:
  A negative integer, zero, or a positive integer if this module descriptor is less than, equal to, or greater than the given module descriptor
- equals
  public boolean equals(Object ob)
  Tests this module descriptor for equality with the given object.
  If the given object is not aModuleDescriptor then this method returnsfalse. Two module descriptors are equal if each of their corresponding components is equal.
  This method satisfies the general contract of theObject.equals method.
  Overrides:
  equals in class Object
  Parameters:
  ob - the object to which this object is to be compared
  Returns:
  true if, and only if, the given object is a module descriptor that is equal to this module descriptor
  See Also:
  Object.hashCode()
  HashMap
- hashCode
  public int hashCode()
  Computes a hash code for this module descriptor.
  The hash code is based upon the components of the module descriptor, and satisfies the general contract of theObject.hashCode method.
  Overrides:
  hashCode in class Object
  Returns:
  The hash-code value for this module descriptor
  See Also:
  Object.equals(java.lang.Object)
  System.identityHashCode(java.lang.Object)
- toString
  public String toString()
  Returns a string describing the module.
  Overrides:
  toString in class Object
  Returns:
  A string describing the module
- newModule
  public static ModuleDescriptor.Builder newModule(String name,Set<ModuleDescriptor.Modifier> ms)
  Instantiates a builder to build a module descriptor.
  Parameters:
  name - The module name
  ms - The set of module modifiers
  Returns:
  A new builder
  Throws:
  IllegalArgumentException - If the module name isnull or is not a legal module name, or the set of modifiers containsAUTOMATIC with other modifiers
- newModule
  public static ModuleDescriptor.Builder newModule(String name)
  Instantiates a builder to build a module descriptor for anormal module. This method is equivalent to invokingnewModule with an empty set ofmodifiers.
  Parameters:
  name - The module name
  Returns:
  A new builder
  Throws:
  IllegalArgumentException - If the module name isnull or is not a legal module name
- newOpenModule
  public static ModuleDescriptor.Builder newOpenModule(String name)
  Instantiates a builder to build a module descriptor for an open module. This method is equivalent to invokingnewModule with theOPEN modifier.
  The builder for an open module cannot be used to declare any open packages.
  Parameters:
  name - The module name
  Returns:
  A new builder that builds an open module
  Throws:
  IllegalArgumentException - If the module name isnull or is not a legal module name
- newAutomaticModule
  public static ModuleDescriptor.Builder newAutomaticModule(String name)
  Instantiates a builder to build a module descriptor for an automatic module. This method is equivalent to invokingnewModule with theAUTOMATIC modifier.
  The builder for an automatic module cannot be used to declare module or service dependences. It also cannot be used to declare any exported or open packages.
  Parameters:
  name - The module name
  Returns:
  A new builder that builds an automatic module
  Throws:
  IllegalArgumentException - If the module name isnull or is not a legal module name
  See Also:
  ModuleFinder.of(Path[])
- read
  public static ModuleDescriptor read(InputStream in,Supplier<Set<String>> packageFinder) throwsIOException
  Reads the binary form of a module declaration from an input stream as a module descriptor.
  If the descriptor encoded in the input stream does not indicate a set of packages in the module then thepackageFinder will be invoked. The set of packages that thepackageFinder returns must include all the packages that the module exports, opens, as well as the packages of the service implementations that the module provides, and the package of the main class (if the module has a main class). If thepackageFinder throws anUncheckedIOException thenIOException cause will be re-thrown.
  If there are bytes following the module descriptor then it is implementation specific as to whether those bytes are read, ignored, or reported as anInvalidModuleDescriptorException. If this method fails with anInvalidModuleDescriptorException or IOException then it may do so after some, but not all, bytes have been read from the input stream. It is strongly recommended that the stream be promptly closed and discarded if an exception occurs.
  API Note:
  ThepackageFinder parameter is for use when reading module descriptors from legacy module-artifact formats that do not record the set of packages in the descriptor itself.
  Parameters:
  in - The input stream
  packageFinder - A supplier that can produce the set of packages
  Returns:
  The module descriptor
  Throws:
  InvalidModuleDescriptorException - If an invalid module descriptor is detected or the set of packages returned by thepackageFinder does not include all of the packages obtained from the module descriptor
  IOException - If an I/O error occurs reading from the input stream or UncheckedIOException is thrown by the package finder
- read
  public static ModuleDescriptor read(InputStream in) throwsIOException
  Reads the binary form of a module declaration from an input stream as a module descriptor. This method works exactly as specified by the 2-argread method with the exception that a package finder is not used to find additional packages when the module descriptor read from the stream does not indicate the set of packages.
  Parameters:
  in - The input stream
  Returns:
  The module descriptor
  Throws:
  InvalidModuleDescriptorException - If an invalid module descriptor is detected
  IOException - If an I/O error occurs reading from the input stream
- read
  public static ModuleDescriptor read(ByteBuffer bb,Supplier<Set<String>> packageFinder)
  Reads the binary form of a module declaration from a byte buffer as a module descriptor.
  If the descriptor encoded in the byte buffer does not indicate a set of packages in the module then thepackageFinder will be invoked. The set of packages that thepackageFinder returns must include all the packages that the module exports, opens, as well as the packages of the service implementations that the module provides, and the package of the main class (if the module has a main class). If thepackageFinder throws anUncheckedIOException thenIOException cause will be re-thrown.
  The module descriptor is read from the buffer starting at indexp, wherep is the buffer'sposition when this method is invoked. Upon return the buffer's position will be equal top + n wheren is the number of bytes read from the buffer.
  If there are bytes following the module descriptor then it is implementation specific as to whether those bytes are read, ignored, or reported as anInvalidModuleDescriptorException. If this method fails with anInvalidModuleDescriptorException then it may do so after some, but not all, bytes have been read.
  API Note:
  ThepackageFinder parameter is for use when reading module descriptors from legacy module-artifact formats that do not record the set of packages in the descriptor itself.
  Parameters:
  bb - The byte buffer
  packageFinder - A supplier that can produce the set of packages
  Returns:
  The module descriptor
  Throws:
  InvalidModuleDescriptorException - If an invalid module descriptor is detected or the set of packages returned by thepackageFinder does not include all of the packages obtained from the module descriptor
- read
  public static ModuleDescriptor read(ByteBuffer bb)
  Reads the binary form of a module declaration from a byte buffer as a module descriptor. This method works exactly as specified by the 2-argread method with the exception that a package finder is not used to find additional packages when the module descriptor encoded in the buffer does not indicate the set of packages.
  Parameters:
  bb - The byte buffer
  Returns:
  The module descriptor
  Throws:
  InvalidModuleDescriptorException - If an invalid module descriptor is detected

Movatterモバイル変換

Class ModuleDescriptor

Nested Class Summary

Method Summary

Methods declared in class java.lang.Object

Method Details

name

modifiers

accessFlags

isOpen

isAutomatic

requires

exports

opens

uses

provides

version

rawVersion

toNameAndVersion

mainClass

packages

compareTo

equals

hashCode

toString

newModule

newModule

newOpenModule

newAutomaticModule

read

read

read

read