/*
 * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation. Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package java.lang;

import java.lang.module.Configuration;
import java.lang.module.ModuleReference;
import java.net.URI;

/**
 * A NamedPackage represents a package by name in a specific module.
 *
 * A class loader will automatically create NamedPackage for each
 * package when a class is defined. Package object is lazily
 * defined until Class::getPackage, Package::getPackage(s), or
 * ClassLoader::getDefinedPackage(s) method is called.
 *
 * NamedPackage allows ClassLoader to keep track of the runtime
 * packages with minimal footprint and avoid constructing Package
 * object.
 */
class NamedPackage {
 private final String name;
 private final Module module;

 NamedPackage(String pn, Module module) {
 if (pn.isEmpty() && module.isNamed()) {
 throw new InternalError("unnamed package in " + module);
 }
 this.name = pn.intern();
 this.module = module;
 }

 /**
 * Returns the name of this package.
 */
 String packageName() {
 return name;
 }

 /**
 * Returns the module of this named package.
 */
 Module module() {
 return module;
 }

 /**
 * Returns the location of the module if this named package is in
 * a named module; otherwise, returns null.
 */
 URI location() {
 if (module.isNamed() && module.getLayer() != null) {
 Configuration cf = module.getLayer().configuration();
 ModuleReference mref
 = cf.findModule(module.getName()).get().reference();
 return mref.location().orElse(null);
 }
 return null;
 }

 /**
 * Creates a Package object of the given name and module.
 */
 static Package toPackage(String name, Module module) {
 return new Package(name, module);
 }
}