1 files changed, 92 insertions, 0 deletions
diff --git a/src/main/java/org/junit/internal/management/ReflectiveThreadMXBean.java b/src/main/java/org/junit/internal/management/ReflectiveThreadMXBean.java
new file mode 100644
index 0000000..bc741be
--- /dev/null
+++ b/src/main/java/org/junit/internal/management/ReflectiveThreadMXBean.java
@@ -0,0 +1,92 @@
+package org.junit.internal.management;
+
+import org.junit.internal.Classes;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+/**
+ * Implementation of {@link ThreadMXBean} using the JVM reflectively.
+ */
+final class ReflectiveThreadMXBean implements ThreadMXBean {
+  private final Object threadMxBean;
+
+
+  private static final class Holder {
+    static final Method getThreadCpuTimeMethod;
+    static final Method isThreadCpuTimeSupportedMethod;
+
+    private static final String FAILURE_MESSAGE = "Unable to access ThreadMXBean";
+
+    static {
+      Method threadCpuTime = null;
+      Method threadCpuTimeSupported = null;
+      try {
+        Class<?> threadMXBeanClass = Classes.getClass("java.lang.management.ThreadMXBean");
+        threadCpuTime = threadMXBeanClass.getMethod("getThreadCpuTime", long.class);
+        threadCpuTimeSupported = threadMXBeanClass.getMethod("isThreadCpuTimeSupported");
+      } catch (ClassNotFoundException e) {
+        // do nothing, the methods will be null on failure
+      } catch (NoSuchMethodException e) {
+        // do nothing, the methods will be null on failure
+      } catch (SecurityException e) {
+        // do nothing, the methods will be null on failure
+      }
+      getThreadCpuTimeMethod = threadCpuTime;
+      isThreadCpuTimeSupportedMethod = threadCpuTimeSupported;
+    }
+  }
+
+  ReflectiveThreadMXBean(Object threadMxBean) {
+    super();
+    this.threadMxBean = threadMxBean;
+  }
+
+  /**
+   * {@inheritDoc}
+   */
+  public long getThreadCpuTime(long id) {
+    if (Holder.getThreadCpuTimeMethod != null) {
+      Exception error = null;
+      try {
+        return (Long) Holder.getThreadCpuTimeMethod.invoke(threadMxBean, id);
+      } catch (ClassCastException e) {
+        error = e;
+        // fallthrough
+      } catch (IllegalAccessException e) {
+        error = e;
+        // fallthrough
+      } catch (IllegalArgumentException e) {
+        error = e;
+        // fallthrough
+      } catch (InvocationTargetException e) {
+        error = e;
+        // fallthrough
+      }
+      throw new UnsupportedOperationException(Holder.FAILURE_MESSAGE, error);
+    }
+    throw new UnsupportedOperationException(Holder.FAILURE_MESSAGE);
+  }
+
+  /**
+   * {@inheritDoc}
+   */
+  public boolean isThreadCpuTimeSupported() {
+    if (Holder.isThreadCpuTimeSupportedMethod != null) {
+      try {
+        return (Boolean) Holder.isThreadCpuTimeSupportedMethod.invoke(threadMxBean);
+      } catch (ClassCastException e) {
+        // fallthrough
+      } catch (IllegalAccessException e) {
+        // fallthrough
+      } catch (IllegalArgumentException e) {
+        // fallthrough
+      } catch (InvocationTargetException e) {
+        // fallthrough
+      }
+    }
+    return false;
+  }
+
+}
+