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Provides minimum set of core utilities required by all OSGL libraries
package org.osgl.bootstrap;
/*-
* #%L
* OSGL Bootstrap
* %%
* Copyright (C) 2017 OSGL (Open Source General Library)
* %%
* 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.
* #L%
*/
import java.util.Properties;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
/**
* Represent **version** of a specific Java library.
*
* The version contains two piece of information:
*
* * maven project version, which is defined by `${project.version}`
* * scm build version, usually provided by
* [buildnumber-maven-plugin](http://www.mojohaus.org/buildnumber-maven-plugin/)
*
* # Usage
*
* ## 1. Prepare version file
*
* Application or library developer put a file named `.version` into a dir corresponding
* to app/lib's package inside the `resources` dir. For example if a library package
* name is `org.mrcool.swissknife`, then put the `.version` file under
*
* ```
* src/main/resources/org/mrcool/swissknife`
* ```
*
* The content of the `.version` file should be
*
* ```
* version=${project.version}
* build=${buildNumber} # optional
* ```
*
* **Note** don't forget to set resource filter in the library's `pom.xml` file:
*
* ```
*
*
* src/main/resources
* true
*
*
* ```
*
* **Note** as a general rule, do **NOT** put the `.version` file for the first level
* package, e.g. `org`, `com`, `net` etc. Version tool will never read the `.version`
* file for a package name that does not contain a `.` inside
*
* ## 2. Retrieve the version info
*
* In order to obtain the version information about a library or app's class, one can use
* the API provided by this `Version` class:
*
* ```java
* Version swissKnifeVersion = Version.of(org.mrcool.siwssknife.SwissKnife.class);
* ```
*/
public final class Version {
public static final String UNKNOWN_STR = "unknown";
public static final Version UNKNOWN = new Version(UNKNOWN_STR, UNKNOWN_STR);
private static final ConcurrentMap cache = new ConcurrentHashMap();
private final String projectVersion;
private final String buildNumber;
private Version(String projectVersion, String buildNumber) {
if (null == projectVersion || "".equals(projectVersion.trim())) {
throw new IllegalArgumentException("project version is empty");
}
this.projectVersion = projectVersion.trim();
this.buildNumber = isBlank(buildNumber) ? "" : buildNumber.trim();
}
/**
* Returns project version which is defined in `${project.version}` maven environment variable
*
* @return the project version
*/
public String getProjectVersion() {
return projectVersion;
}
/**
* Returns the build number which is defined in `${buildNumber}` maven environment variable when
* [buildnumber-maven-plugin](http://www.mojohaus.org/buildnumber-maven-plugin/) is provided
*
* @return the SCM build number
*/
public String getBuildNumber() {
return buildNumber;
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
Version version = (Version) o;
if (!projectVersion.equals(version.projectVersion)) {
return false;
}
return buildNumber != null ? buildNumber.equals(version.buildNumber) : version.buildNumber == null;
}
@Override
public int hashCode() {
int result = projectVersion.hashCode();
result = 31 * result + (buildNumber != null ? buildNumber.hashCode() : 0);
return result;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder(projectVersion);
if (!isBlank(buildNumber)) {
sb.append("-").append(buildNumber);
}
return sb.toString();
}
/**
* Returns a `Version` corresponding to the package name specified.
*
* This method will tried to check if {@link #cache local cache} contains
* the package name first, and return the version instance mapped to the
* package name in local cache, or if not found in local cache try to load
* the `.version` file as a resource corresponding to the package name.
*
* If the `.version` file not found, this method will try to get version
* of parent package until the package name is empty, in which case
* the {@link #UNKNOWN} will be returned
*
* @param packageName the package name
* @return a `Version` instance for that package
*/
public static Version of(String packageName) {
if (!isValidPackageName(packageName)) {
throw new IllegalArgumentException("package name is not valid: " + packageName);
}
return of_(packageName);
}
/**
* Returns a `Version` of the library contains the class of the object
* specified.
*
* @param object the object
* @return a `Version` for that class if provided or
* {@link #UNKNOWN} if not provided
* @throws NullPointerException if the object specified is `null`
* @see #of(String)
*/
public static Version of(Object object) {
return object instanceof Class ? of((Class) object) : of(object.getClass());
}
/**
* Returns a `Version` of the library contains the class specified.
*
* @param clazz the class
* @return a `Version` for that class if provided or
* {@link #UNKNOWN} if not provided
* @throws NullPointerException if the class specified is `null`
* @see #of(String)
*/
public static Version of(Class clazz) {
String className = clazz.getName();
int pos = className.lastIndexOf('.');
if (pos < 0) {
return UNKNOWN;
}
String packageName = className.substring(0, pos);
return of_(packageName);
}
/**
* Returns a `Version` of the library contains the package specified.
*
* @param pkg the package
* @return a `Version` for the package if provided or
* {@link #UNKNOWN} if not provided
* @throws NullPointerException if the class specified is `null`
* @see #of(String)
*/
public static Version of(Package pkg) {
return of_(pkg.getName());
}
private static Version of_(String packageName) {
if (!packageName.contains(".")) {
return UNKNOWN;
}
Version version = cache.get(packageName);
if (null != version) {
return version;
}
version = loadFromResource(packageName);
if (null == version) {
int pos = packageName.lastIndexOf('.');
if (pos < 0) {
return UNKNOWN;
}
return of(packageName.substring(0, pos));
}
cache.put(packageName, version);
return version;
}
private static boolean isBlank(String s) {
return null == s || "".equals(s.trim());
}
private static Version loadFromResource(String packageName) {
Properties properties = PropertyLoader.INSTANCE.loadFromResource(packageName);
return null == properties ? null : loadFrom(properties);
}
private static Version loadFrom(Properties properties) {
String projectVersion = properties.getProperty("version");
String buildNumber = properties.getProperty("build");
return new Version(projectVersion, buildNumber);
}
private static boolean isValidPackageName(String s) {
if (null == s) {
return false;
}
int len = s.length();
if (0 == len) {
return false;
}
char[] ca = s.toCharArray();
if (!Character.isJavaIdentifierStart(ca[0])) {
return false;
}
boolean lastTimeIsDot = false;
for (int i = 1; i < len; i++) {
char c = ca[i];
if ('.' == c) {
if (lastTimeIsDot) {
return false;
} else {
lastTimeIsDot = true;
}
continue;
}
lastTimeIsDot = false;
if (!Character.isJavaIdentifierPart(ca[i])) {
return false;
}
}
return true;
}
static void clearCache() {
cache.clear();
}
}
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