OpenJDK 27 · java.lang.module.ModuleDescriptor · APIdia, the JavaDoc alternative

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 the Module's getDescriptor method. Module descriptors can also be created using the ModuleDescriptor.Builder class or by reading the binary form of a module declaration (module-info.class) using the read methods defined here.

A module descriptor describes a normal, open, or automatic module. Normal modules and open modules describe their dependences, exported-packages, the services that they use or provide, and other components. Normal modules may open specific packages. The module descriptor for an open module does not declare any open packages (its opens 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.

Modifier and Type	Class and Description
public static class	ModuleDescriptor.Builder A builder for building `ModuleDescriptor` objects.
public static class	ModuleDescriptor.Exports A package exported by a module, may be qualified or unqualified.
public static enum	ModuleDescriptor.Modifier A modifier on a module.
public static class	ModuleDescriptor.Opens A package opened by a module, may be qualified or unqualified.
public static class	ModuleDescriptor.Provides A service that a module provides one or more implementations of.
public static class	ModuleDescriptor.Requires A dependence upon a module.
public static class	ModuleDescriptor.Version A module's version string.

Modifier and Type	Field and Description
private final boolean	automatic
private final Set<ModuleDescriptor.Exports>	exports
private transient int	hash
private final String	mainClass
private final Set<ModuleDescriptor.Modifier>	modifiers
private final String	name
private final boolean	open
private final Set<ModuleDescriptor.Opens>	opens
private final Set<String>	packages
private final Set<ModuleDescriptor.Provides>	provides
private final String	rawVersionString
private final Set<ModuleDescriptor.Requires>	requires
private final Set<String>	uses
private final ModuleDescriptor.Version	version

Access	Constructor and Description
private	ModuleDescriptor(String name, ModuleDescriptor.Version version, String rawVersionString, Set<ModuleDescriptor.Modifier> modifiers, Set<ModuleDescriptor.Requires> requires, Set<ModuleDescriptor.Exports> exports, Set<ModuleDescriptor.Opens> opens, Set<String> uses, Set<ModuleDescriptor.Provides> provides, Set<String> packages, String mainClass)
private	ModuleDescriptor(String name, ModuleDescriptor.Version version, Set<ModuleDescriptor.Modifier> modifiers, Set<ModuleDescriptor.Requires> requires, Set<ModuleDescriptor.Exports> exports, Set<ModuleDescriptor.Opens> opens, Set<String> uses, Set<ModuleDescriptor.Provides> provides, Set<String> packages, String mainClass, int hashCode, boolean unused) Creates a module descriptor from its components.

Method Summary

Modifier and Type	Method and Description
public Set<AccessFlag>	Returns: A possibly-empty unmodifiable set of module flags accessFlags() Returns the set of the module flags.
private static <T extends Comparable<? super T>> int	compare(T obj1, T obj2)
private static <T extends Comparable<? super T>> int	compare(Set<T> s1, Set<T> s2) Compares two sets of `Comparable` objects.
public int	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 compareTo(ModuleDescriptor The module descriptor to compare that) Implements java.lang.Comparable.compareTo. Compares this module descriptor to another.
public boolean	Returns: `true` if, and only if, the given object is a module descriptor that is equal to this module descriptor equals(Object the object to which this object is to be compared ob) Overrides java.lang.Object.equals. Tests this module descriptor for equality with the given object.
public Set<ModuleDescriptor.Exports>	Returns: A possibly-empty unmodifiable set of exported packages exports() Returns the set of `Exports` objects representing the exported packages.
public int	Returns: The hash-code value for this module descriptor hashCode() Overrides java.lang.Object.hashCode. Computes a hash code for this module descriptor.
public boolean	Returns: `true` if this is an automatic module isAutomatic() Returns `true` if this is an automatic module.
public boolean	Returns: `true` if this is an open module isOpen() Returns `true` if this is an open module.
public Optional<String>	Returns: The binary name of the module's main class mainClass() Returns the module main class.
public Set<ModuleDescriptor.Modifier>	Returns: A possibly-empty unmodifiable set of modifiers modifiers() Returns the set of module modifiers.
private static int	modsHashCode(Iterable<? extends Enum<?>> enums) Generates and returns a hashcode for the enum instances.
private static <E extends Enum<E>> long	modsValue(Set<E> set)
public String	Returns: The module name name() Returns the module name.
public static ModuleDescriptor.Builder	Returns: A new builder that builds an automatic module newAutomaticModule(String The module name name) Instantiates a builder to build a module descriptor for an automatic module.
public static ModuleDescriptor.Builder	Returns: A new builder newModule(String The module name name, Set<ModuleDescriptor.Modifier> The set of module modifiers ms) Instantiates a builder to build a module descriptor.
public static ModuleDescriptor.Builder	Returns: A new builder newModule(String The module name name) Instantiates a builder to build a module descriptor for a normal module.
public static ModuleDescriptor.Builder	Returns: A new builder that builds an open module newOpenModule(String The module name name) Instantiates a builder to build a module descriptor for an open module.
public Set<ModuleDescriptor.Opens>	Returns: A possibly-empty unmodifiable set of open packages opens() Returns the set of `Opens` objects representing the open packages.
private static String	packageName(String cn)
public Set<String>	Returns: A possibly-empty unmodifiable set of the packages in the module packages() Returns the set of all packages in the module.
public Set<ModuleDescriptor.Provides>	Returns: The possibly-empty unmodifiable set of the services that this module provides provides() Returns the set of `Provides` objects representing the services that the module provides.
public Optional<String>	Returns: The string containing the version of the module or an empty `Optional` if the module does not have a version rawVersion() Returns the string with the possibly-unparseable version of the module.
public static ModuleDescriptor	Returns: The module descriptor read(InputStream The input stream in, Supplier<Set<String>> A supplier that can produce the set of packages packageFinder) Reads the binary form of a module declaration from an input stream as a module descriptor.
public static ModuleDescriptor	Returns: The module descriptor read(InputStream The input stream in) Reads the binary form of a module declaration from an input stream as a module descriptor.
public static ModuleDescriptor	Returns: The module descriptor read(ByteBuffer The byte buffer bb, Supplier<Set<String>> A supplier that can produce the set of packages packageFinder) Reads the binary form of a module declaration from a byte buffer as a module descriptor.
public static ModuleDescriptor	Returns: The module descriptor read(ByteBuffer The byte buffer bb) Reads the binary form of a module declaration from a byte buffer as a module descriptor.
public Set<ModuleDescriptor.Requires>	Returns: A possibly-empty unmodifiable set of `Requires` objects requires() Returns the set of `Requires` objects representing the module dependences.
public String	Returns: A string containing the module name and, if present, its version toNameAndVersion() Returns a string containing the module name and, if present, its version.
public String	Returns: A string describing the module toString() Overrides java.lang.Object.toString. Returns a string describing the module.
private static <M> String	toString(Set<M> mods, String what) Returns a string containing the given set of modifiers and label.
public Set<String>	Returns: A possibly-empty unmodifiable set of the binary names of the service types used uses() Returns the set of service dependences.
public Optional<ModuleDescriptor.Version>	Returns: This module's version, or an empty `Optional` if the module does not have a version or the version is unparseable version() Returns the module version.

Inherited from java.lang.Object:: clone finalize getClass notify notifyAll wait wait wait

public final Class ModuleDescriptor

Nested and Inner Type Summary

Field Summary

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Method Summary