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/*
 * ====================================================================
 * 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
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 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
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 * This software consists of voluntary contributions made by many
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package org.apache.http.util;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Properties;

/**
 * Provides access to version information for HTTP components.
 * Static methods are used to extract version information from property
 * files that are automatically packaged with HTTP component release JARs.
 * 

* All available version information is provided in strings, where * the string format is informal and subject to change without notice. * Version information is provided for debugging output and interpretation * by humans, not for automated processing in applications. *

* * @since 4.0 */ public class VersionInfo { /** A string constant for unavailable information. */ public final static String UNAVAILABLE = "UNAVAILABLE"; /** The filename of the version information files. */ public final static String VERSION_PROPERTY_FILE = "version.properties"; // the property names public final static String PROPERTY_MODULE = "info.module"; public final static String PROPERTY_RELEASE = "info.release"; public final static String PROPERTY_TIMESTAMP = "info.timestamp"; /** The package that contains the version information. */ private final String infoPackage; /** The module from the version info. */ private final String infoModule; /** The release from the version info. */ private final String infoRelease; /** The timestamp from the version info. */ private final String infoTimestamp; /** The classloader from which the version info was obtained. */ private final String infoClassloader; /** * Instantiates version information. * * @param pckg the package * @param module the module, or {@code null} * @param release the release, or {@code null} * @param time the build time, or {@code null} * @param clsldr the class loader, or {@code null} */ protected VersionInfo(final String pckg, final String module, final String release, final String time, final String clsldr) { Args.notNull(pckg, "Package identifier"); infoPackage = pckg; infoModule = (module != null) ? module : UNAVAILABLE; infoRelease = (release != null) ? release : UNAVAILABLE; infoTimestamp = (time != null) ? time : UNAVAILABLE; infoClassloader = (clsldr != null) ? clsldr : UNAVAILABLE; } /** * Obtains the package name. * The package name identifies the module or informal unit. * * @return the package name, never {@code null} */ public final String getPackage() { return infoPackage; } /** * Obtains the name of the versioned module or informal unit. * This data is read from the version information for the package. * * @return the module name, never {@code null} */ public final String getModule() { return infoModule; } /** * Obtains the release of the versioned module or informal unit. * This data is read from the version information for the package. * * @return the release version, never {@code null} */ public final String getRelease() { return infoRelease; } /** * Obtains the timestamp of the versioned module or informal unit. * This data is read from the version information for the package. * * @return the timestamp, never {@code null} */ public final String getTimestamp() { return infoTimestamp; } /** * Obtains the classloader used to read the version information. * This is just the {@code toString} output of the classloader, * since the version information should not keep a reference to * the classloader itself. That could prevent garbage collection. * * @return the classloader description, never {@code null} */ public final String getClassloader() { return infoClassloader; } /** * Provides the version information in human-readable format. * * @return a string holding this version information */ @Override public String toString() { final StringBuilder sb = new StringBuilder (20 + infoPackage.length() + infoModule.length() + infoRelease.length() + infoTimestamp.length() + infoClassloader.length()); sb.append("VersionInfo(") .append(infoPackage).append(':').append(infoModule); // If version info is missing, a single "UNAVAILABLE" for the module // is sufficient. Everything else just clutters the output. if (!UNAVAILABLE.equals(infoRelease)) { sb.append(':').append(infoRelease); } if (!UNAVAILABLE.equals(infoTimestamp)) { sb.append(':').append(infoTimestamp); } sb.append(')'); if (!UNAVAILABLE.equals(infoClassloader)) { sb.append('@').append(infoClassloader); } return sb.toString(); } /** * Loads version information for a list of packages. * * @param pckgs the packages for which to load version info * @param clsldr the classloader to load from, or * {@code null} for the thread context classloader * * @return the version information for all packages found, * never {@code null} */ public static VersionInfo[] loadVersionInfo(final String[] pckgs, final ClassLoader clsldr) { Args.notNull(pckgs, "Package identifier array"); final List vil = new ArrayList(pckgs.length); for (final String pckg : pckgs) { final VersionInfo vi = loadVersionInfo(pckg, clsldr); if (vi != null) { vil.add(vi); } } return vil.toArray(new VersionInfo[vil.size()]); } /** * Loads version information for a package. * * @param pckg the package for which to load version information, * for example "org.apache.http". * The package name should NOT end with a dot. * @param clsldr the classloader to load from, or * {@code null} for the thread context classloader * * @return the version information for the argument package, or * {@code null} if not available */ public static VersionInfo loadVersionInfo(final String pckg, final ClassLoader clsldr) { Args.notNull(pckg, "Package identifier"); final ClassLoader cl = clsldr != null ? clsldr : Thread.currentThread().getContextClassLoader(); Properties vip = null; // version info properties, if available try { // org.apache.http becomes // org/apache/http/version.properties final InputStream is = cl.getResourceAsStream (pckg.replace('.', '/') + "/" + VERSION_PROPERTY_FILE); if (is != null) { try { final Properties props = new Properties(); props.load(is); vip = props; } finally { is.close(); } } } catch (final IOException ex) { // shamelessly munch this exception } VersionInfo result = null; if (vip != null) { result = fromMap(pckg, vip, cl); } return result; } /** * Instantiates version information from properties. * * @param pckg the package for the version information * @param info the map from string keys to string values, * for example {@link java.util.Properties} * @param clsldr the classloader, or {@code null} * * @return the version information */ protected static VersionInfo fromMap(final String pckg, final Map info, final ClassLoader clsldr) { Args.notNull(pckg, "Package identifier"); String module = null; String release = null; String timestamp = null; if (info != null) { module = (String) info.get(PROPERTY_MODULE); if ((module != null) && (module.length() < 1)) { module = null; } release = (String) info.get(PROPERTY_RELEASE); if ((release != null) && ((release.length() < 1) || (release.equals("${pom.version}")))) { release = null; } timestamp = (String) info.get(PROPERTY_TIMESTAMP); if ((timestamp != null) && ((timestamp.length() < 1) || (timestamp.equals("${mvn.timestamp}"))) ) { timestamp = null; } } // if info String clsldrstr = null; if (clsldr != null) { clsldrstr = clsldr.toString(); } return new VersionInfo(pckg, module, release, timestamp, clsldrstr); } /** * Sets the user agent to {@code "/ (Java/)"}. *

* For example: *

"Apache-HttpClient/4.3 (Java/1.6.0_35)"
* * @param name the component name, like "Apache-HttpClient". * @param pkg * the package for which to load version information, for example "org.apache.http". The package name * should NOT end with a dot. * @param cls * the class' class loader to load from, or {@code null} for the thread context class loader * @since 4.3 */ public static String getUserAgent(final String name, final String pkg, final Class cls) { // determine the release version from packaged version info final VersionInfo vi = VersionInfo.loadVersionInfo(pkg, cls.getClassLoader()); final String release = (vi != null) ? vi.getRelease() : VersionInfo.UNAVAILABLE; final String javaVersion = System.getProperty("java.version"); return String.format("%s/%s (Java/%s)", name, release, javaVersion); } } // class VersionInfo




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