com.fitbur.jackson.core.util.VersionUtil Maven / Gradle / Ivy
package com.fitbur.jackson.core.util;
import java.io.*;
import java.util.Properties;
import java.util.regex.Pattern;
import com.fitbur.jackson.core.Version;
import com.fitbur.jackson.core.Versioned;
/**
* Functionality for supporting exposing of component {@link Version}s.
* Also contains other misc methods that have no other place to live in.
*
* Note that this class can be used in two roles: first, as a static
* utility class for loading purposes, and second, as a singleton
* loader of per-module version information.
*
* Note that method for accessing version information changed between versions
* 2.1 and 2.2; earlier code used file named "VERSION.txt"; but this has serious
* performance issues on some platforms (Android), so a replacement system
* was implemented to use class generation and dynamic class loading.
*
* Note that functionality for reading "VERSION.txt" was removed completely
* from Jackson 2.6.
*/
public class VersionUtil
{
private final static Pattern V_SEP = Pattern.compile("[-_./;:]");
private final Version _v;
/*
/**********************************************************
/* Instance life-cycle
/**********************************************************
*/
protected VersionUtil()
{
Version v = null;
try {
/* Class we pass only matters for resource-loading: can't use this Class
* (as it's just being loaded at this point), nor anything that depends on it.
*/
v = VersionUtil.versionFor(getClass());
} catch (Exception e) { // not good to dump to stderr; but that's all we have at this low level
System.err.println("ERROR: Failed to load Version information from "+getClass());
}
if (v == null) {
v = Version.unknownVersion();
}
_v = v;
}
public Version version() { return _v; }
/*
/**********************************************************
/* Static load methods
/**********************************************************
*/
/**
* Helper method that will try to load version information for specified
* class. Implementation is as follows:
*
* First, tries to load version info from a class named
* "PackageVersion" in the same package as the class.
*
* If no version information is found, {@link Version#unknownVersion()} is returned.
*/
public static Version versionFor(Class cls)
{
Version version = packageVersionFor(cls);
return version == null ? Version.unknownVersion() : version;
}
/**
* Loads version information by introspecting a class named
* "PackageVersion" in the same package as the given class.
*
* If the class could not be found or does not have a public
* static Version field named "VERSION", returns null.
*/
public static Version packageVersionFor(Class cls)
{
Version v = null;
try {
String versionInfoClassName = cls.getPackage().getName() + ".PackageVersion";
Class vClass = Class.forName(versionInfoClassName, true, cls.getClassLoader());
// However, if class exists, it better work correctly, no swallowing exceptions
try {
v = ((Versioned) vClass.newInstance()).version();
} catch (Exception e) {
throw new IllegalArgumentException("Failed to get Versioned out of "+vClass);
}
} catch (Exception e) { // ok to be missing (not good but acceptable)
;
}
return (v == null) ? Version.unknownVersion() : v;
}
/**
* Will attempt to load the maven version for the given groupId and
* artifactId. Maven puts a pom.properties file in
* META-INF/maven/groupId/artifactId, containing the groupId,
* artifactId and version of the library.
*
* @param cl the ClassLoader to load the pom.properties file from
* @param groupId the groupId of the library
* @param artifactId the artifactId of the library
* @return The version
*
* @deprecated Since 2.6: functionality not used by any official Jackson component, should be
* moved out if anyone needs it
*/
@SuppressWarnings("resource")
@Deprecated // since 2.6
public static Version mavenVersionFor(ClassLoader cl, String groupId, String artifactId)
{
InputStream pomProperties = cl.getResourceAsStream("META-INF/maven/"
+ groupId.replaceAll("\\.", "/")+ "/" + artifactId + "/pom.properties");
if (pomProperties != null) {
try {
Properties props = new Properties();
props.load(pomProperties);
String versionStr = props.getProperty("version");
String pomPropertiesArtifactId = props.getProperty("artifactId");
String pomPropertiesGroupId = props.getProperty("groupId");
return parseVersion(versionStr, pomPropertiesGroupId, pomPropertiesArtifactId);
} catch (IOException e) {
// Ignore
} finally {
_close(pomProperties);
}
}
return Version.unknownVersion();
}
/**
* Method used by PackageVersion classes to decode version injected by Maven build.
*/
public static Version parseVersion(String s, String groupId, String artifactId)
{
if (s != null && (s = s.trim()).length() > 0) {
String[] parts = V_SEP.split(s);
return new Version(parseVersionPart(parts[0]),
(parts.length > 1) ? parseVersionPart(parts[1]) : 0,
(parts.length > 2) ? parseVersionPart(parts[2]) : 0,
(parts.length > 3) ? parts[3] : null,
groupId, artifactId);
}
return Version.unknownVersion();
}
protected static int parseVersionPart(String s) {
int number = 0;
for (int i = 0, len = s.length(); i < len; ++i) {
char c = s.charAt(i);
if (c > '9' || c < '0') break;
number = (number * 10) + (c - '0');
}
return number;
}
private final static void _close(Closeable c) {
try {
c.close();
} catch (IOException e) { }
}
/*
/**********************************************************
/* Orphan utility methods
/**********************************************************
*/
public final static void throwInternal() {
throw new RuntimeException("Internal error: this code path should never get executed");
}
}