java.lang.module.ModuleReference Maven / Gradle / Ivy
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* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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package java.lang.module;
import java.io.IOException;
import java.net.URI;
import java.util.Objects;
import java.util.Optional;
/**
* A reference to a module's content.
*
* A module reference is a concrete implementation of this class that
* implements the abstract methods defined by this class. It contains the
* module's descriptor and its location, if known. It also has the ability to
* create a {@link ModuleReader} in order to access the module's content, which
* may be inside the Java run-time system itself or in an artifact such as a
* modular JAR file.
*
* @see ModuleFinder
* @see ModuleReader
* @since 9
*/
public abstract class ModuleReference {
private final ModuleDescriptor descriptor;
private final URI location;
/**
* Constructs a new instance of this class.
*
* @param descriptor
* The module descriptor
* @param location
* The module location or {@code null} if not known
*/
protected ModuleReference(ModuleDescriptor descriptor, URI location) {
this.descriptor = Objects.requireNonNull(descriptor);
this.location = location;
}
/**
* Returns the module descriptor.
*
* @return The module descriptor
*/
public final ModuleDescriptor descriptor() {
return descriptor;
}
/**
* Returns the location of this module's content, if known.
*
*
This URI, when present, can be used as the {@linkplain
* java.security.CodeSource#getLocation location} value of a {@link
* java.security.CodeSource CodeSource} so that a module's classes can be
* granted specific permissions when loaded by a {@link
* java.security.SecureClassLoader SecureClassLoader}.
*
* @return The location or an empty {@code Optional} if not known
*/
public final Optional location() {
return Optional.ofNullable(location);
}
/**
* Opens the module content for reading.
*
* @return A {@code ModuleReader} to read the module
*
* @throws IOException
* If an I/O error occurs
* @throws SecurityException
* If denied by the security manager
*/
public abstract ModuleReader open() throws IOException;
}