All Downloads are FREE. Search and download functionalities are using the official Maven repository.

java.lang.Package Maven / Gradle / Ivy

There is a newer version: 1.2.9
Show newest version
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package java.lang;

import dalvik.system.VMStack;
import java.lang.annotation.Annotation;
import java.lang.reflect.AnnotatedElement;
import java.net.URL;

/**
 * Contains information about a Java package. This includes implementation and
 * specification versions. Typically this information is retrieved from the
 * manifest.
 * 

* Packages are managed by class loaders. All classes loaded by the same loader * from the same package share a {@code Package} instance. *

* * @see java.lang.ClassLoader */ public class Package implements AnnotatedElement { private static final Annotation[] NO_ANNOTATIONS = new Annotation[0]; private final String name; private final String specTitle; private final String specVersion; private final String specVendor; private final String implTitle; private final String implVersion; private final String implVendor; private final URL sealBase; Package(String name, String specTitle, String specVersion, String specVendor, String implTitle, String implVersion, String implVendor, URL sealBase) { this.name = name; this.specTitle = specTitle; this.specVersion = specVersion; this.specVendor = specVendor; this.implTitle = implTitle; this.implVersion = implVersion; this.implVendor = implVendor; this.sealBase = sealBase; } /** * Returns the annotation associated with the specified annotation type and * this package, if present. * * @param annotationType * the annotation type to look for. * @return an instance of {@link Annotation} or {@code null}. * @see java.lang.reflect.AnnotatedElement#getAnnotation(java.lang.Class) */ @SuppressWarnings("unchecked") public A getAnnotation(Class annotationType) { for (Annotation annotation : getAnnotations()) { if (annotationType.isInstance(annotation)) { return (A) annotation; } } return null; } /** * Returns an array of this package's annotations. */ public Annotation[] getAnnotations() { try { Class c = Class.forName(getName() + ".package-info"); return c.getAnnotations(); } catch (Exception ex) { return NO_ANNOTATIONS; } } /** * Returns an array of this package's declared annotations. Package annotations aren't * inherited, so this is equivalent to {@link #getAnnotations}. */ public Annotation[] getDeclaredAnnotations() { return getAnnotations(); } /** * Indicates whether the specified annotation is present. * * @param annotationType * the annotation type to look for. * @return {@code true} if the annotation is present; {@code false} * otherwise. * @see java.lang.reflect.AnnotatedElement#isAnnotationPresent(java.lang.Class) */ public boolean isAnnotationPresent(Class annotationType) { return getAnnotation(annotationType) != null; } /** * Returns the title of the implementation of this package, or {@code null} * if this is unknown. The format of this string is unspecified. * * @return the implementation title, may be {@code null}. */ public String getImplementationTitle() { return implTitle; } /** * Returns the name of the vendor or organization that provides this * implementation of the package, or {@code null} if this is unknown. The * format of this string is unspecified. * * @return the implementation vendor name, may be {@code null}. */ public String getImplementationVendor() { return implVendor; } /** * Returns the version of the implementation of this package, or {@code * null} if this is unknown. The format of this string is unspecified. * * @return the implementation version, may be {@code null}. */ public String getImplementationVersion() { return implVersion; } /** * Returns the name of this package in the standard dot notation; for * example: "java.lang". * * @return the name of this package. */ public String getName() { return name; } /** * Attempts to locate the requested package in the caller's class loader. If * no package information can be located, {@code null} is returned. * * @param packageName * the name of the package to find. * @return the requested package, or {@code null}. * @see ClassLoader#getPackage(java.lang.String) */ public static Package getPackage(String packageName) { ClassLoader classloader = VMStack.getCallingClassLoader(); if (classloader == null) { classloader = ClassLoader.getSystemClassLoader(); } return classloader.getPackage(packageName); } /** * Returns all the packages known to the caller's class loader. * * @return all the packages known to the caller's class loader. * @see ClassLoader#getPackages */ public static Package[] getPackages() { ClassLoader classloader = VMStack.getCallingClassLoader(); if (classloader == null) { classloader = ClassLoader.getSystemClassLoader(); } return classloader.getPackages(); } /** * Returns the title of the specification this package implements, or * {@code null} if this is unknown. * * @return the specification title, may be {@code null}. */ public String getSpecificationTitle() { return specTitle; } /** * Returns the name of the vendor or organization that owns and maintains * the specification this package implements, or {@code null} if this is * unknown. * * @return the specification vendor name, may be {@code null}. */ public String getSpecificationVendor() { return specVendor; } /** * Returns the version of the specification this package implements, or * {@code null} if this is unknown. The version string is a sequence of * non-negative integers separated by dots; for example: "1.2.3". * * @return the specification version string, may be {@code null}. */ public String getSpecificationVersion() { return specVersion; } @Override public int hashCode() { return name.hashCode(); } /** * Indicates whether this package's specification version is compatible with * the specified version string. Version strings are compared by comparing * each dot separated part of the version as an integer. * * @param version * the version string to compare against. * @return {@code true} if the package versions are compatible; {@code * false} otherwise. * @throws NumberFormatException * if this package's version string or the one provided are not * in the correct format. */ public boolean isCompatibleWith(String version) throws NumberFormatException { String[] requested = version.split("\\."); String[] provided = specVersion.split("\\."); for (int i = 0; i < Math.min(requested.length, provided.length); i++) { int reqNum = Integer.parseInt(requested[i]); int provNum = Integer.parseInt(provided[i]); if (reqNum > provNum) { return false; } else if (reqNum < provNum) { return true; } } if (requested.length > provided.length) { return false; } return true; } /** * Indicates whether this package is sealed. * * @return {@code true} if this package is sealed; {@code false} otherwise. */ public boolean isSealed() { return sealBase != null; } /** * Indicates whether this package is sealed with respect to the specified * URL. * * @param url * the URL to check. * @return {@code true} if this package is sealed with {@code url}; {@code * false} otherwise */ public boolean isSealed(URL url) { return sealBase != null && sealBase.sameFile(url); } @Override public String toString() { return "package " + name; } }




© 2015 - 2024 Weber Informatics LLC | Privacy Policy