read version info from from MANIFEST.MF using different strategy (#163)

chewiebug · Feb 15, 2016 · babffd3 · babffd3
1 parent 37376ba
commit babffd3
Showing 1 changed file with 23 additions and 11 deletions.
diff --git a/src/main/java/com/tagtraum/perf/gcviewer/util/BuildInfoReader.java b/src/main/java/com/tagtraum/perf/gcviewer/util/BuildInfoReader.java
@@ -1,8 +1,9 @@
 package com.tagtraum.perf.gcviewer.util;
 
 import java.io.IOException;
-import java.io.InputStream;
-import java.util.Properties;
+import java.net.URL;
+import java.util.jar.Attributes;
+import java.util.jar.Manifest;
 
 /**
  * Small helper class to provide current version of GCViewer.
@@ -13,7 +14,7 @@
  */
 public class BuildInfoReader {
 
-    private final static String FILE_NAME = "META-INF/MANIFEST.MF";
+    private final static String FILE_NAME = "/META-INF/MANIFEST.MF";
     private final static String BUILD_VERSION = "Implementation-Version";
     private final static String BUILD_TIMESTAMP = "Implementation-Date";
 
@@ -25,14 +26,11 @@ public class BuildInfoReader {
      */
     private static String readPropertyValue(String propertyName) {
         String propertyValue = "n/a";
-        try (InputStream in = Thread.currentThread().getContextClassLoader().getResourceAsStream(FILE_NAME)) {
-            if (in != null) {
-                Properties props = new Properties();
-                props.load(in);
-                propertyValue = props.getProperty(propertyName);
-                if (propertyValue == null || propertyValue.length() == 0) {
-                    propertyValue = "n/a";
-                }
+        try {
+            Attributes attributes = getAttributes();
+            propertyValue = attributes.getValue(propertyName);
+            if (propertyValue == null || propertyValue.length() == 0) {
+                propertyValue = "n/a";
             }
         }
         catch (IOException e) {
@@ -42,6 +40,20 @@ private static String readPropertyValue(String propertyName) {
         return propertyValue;
     }
 
+    private static Attributes getAttributes() throws IOException {
+        Class clazz = BuildInfoReader.class;
+        String className = clazz.getSimpleName() + ".class";
+        String classPath = clazz.getResource(className).toString();
+        if (!classPath.startsWith("jar")) {
+            // Class not from JAR
+            return new Attributes(0);
+        }
+        String manifestPath = classPath.substring(0, classPath.lastIndexOf("!") + 1) + FILE_NAME;
+        Manifest manifest = null;
+        manifest = new Manifest(new URL(manifestPath).openStream());
+        return manifest.getMainAttributes();
+    }
+
     /**
      * Read version from properties file in classpath if it can be found.
      *