Merge pull request #411 from scijava/fix-logservice-calling-class

LogService: Make getLevel() more robust against ClassNotFoundException

Author: ctrueden

src/main/java/org/scijava/log/AbstractLogService.java

@@ -104,7 +104,7 @@ public LogSource getSource() {
 	@Override
 	public int getLevel() {
 		if (classAndPackageLevels.isEmpty()) return currentLevel;
-		return getLevelForClass(CallingClassUtils.getCallingClass().getName(),
+		return getLevelForClass(CallingClassUtils.getCallingClassName(),
 			currentLevel);
 	}
 

src/main/java/org/scijava/log/CallingClassUtils.java

@@ -29,6 +29,8 @@
 
 package org.scijava.log;
 
+import org.scijava.Context;
+
 /**
  * Utility class for getting the calling class of a method.
  *
@@ -43,12 +45,44 @@ private CallingClassUtils() {
 	}
 
 	/**
+	 * Inspects the stack trace to return the name of the class that calls
+	 * this method, but ignores every class annotated with @IgnoreAsCallingClass.
+	 * <p>
+	 * If every class on the stack trace is annotated, then the class at the
+	 * root of the stack trace is returned.
+	 */
+	public static String getCallingClassName() {
+		StackTraceElement[] stackTrace = Thread.currentThread().getStackTrace();
+		for (int i = 1; i < stackTrace.length - 2; i++) {
+			String className = stackTrace[i].getClassName();
+			if (!hasIgnoreAsCallingClassAnnotation(className)) return className;
+		}
+		return stackTrace[stackTrace.length - 1].getClassName();
+	}
+
+	private static boolean hasIgnoreAsCallingClassAnnotation(String className) {
+		try {
+			Class< ? > clazz = Context.getClassLoader().loadClass(className);
+			return clazz.isAnnotationPresent(IgnoreAsCallingClass.class);
+		}
+		catch (ClassNotFoundException ignore) {
+			return false;
+		}
+	}
+
+	/**
+	 * @deprecated Use {@link #getCallingClassName()} instead.
+	 *
+	 * Warning: This method throws a IllegalStateException as soon as it comes
+	 * across a class that can't be loaded with the default class loader.
+	 *
 	 * Inspects the stack trace to return the class that calls this method, but
 	 * ignores every class annotated with @IgnoreAsCallingClass.
 	 *
 	 * @throws IllegalStateException if every method on the stack, is in a class
 	 *           annotated with @IgnoreAsCallingClass.
 	 */
+	@Deprecated
 	public static Class<?> getCallingClass() {
 		try {
 			StackTraceElement[] stackTrace = Thread.currentThread().getStackTrace();

src/main/java/org/scijava/log/IgnoreAsCallingClass.java

@@ -34,7 +34,7 @@
 
 /**
  * Classes annotated with {@link IgnoreAsCallingClass} are ignored by
- * {@link CallingClassUtils#getCallingClass()}.
+ * {@link CallingClassUtils#getCallingClassName()}.
  *
  * @author Matthias Arzt
  */

src/test/java/org/scijava/log/CallingClassUtilsTest.java

@@ -31,6 +31,8 @@
 
 import org.junit.Test;
 
+import java.util.function.Supplier;
+
 import static org.junit.Assert.assertEquals;
 
 /**
@@ -41,26 +43,26 @@
 public class CallingClassUtilsTest {
 	@Test
 	public void testGetCallingClass() {
-		Class<?> callingClass = CallingClassUtils.getCallingClass();
-		assertEquals(this.getClass(), callingClass);
+		String callingClass = CallingClassUtils.getCallingClassName();
+		assertEquals(this.getClass().getName(), callingClass);
 	}
 
 	@Test
 	public void testIgnoreAsCallingClass() {
-		assertEquals(ClassA.class, ClassA.returnGetCallingClass());
-		assertEquals(this.getClass(), ClassB.returnGetCallingClass());
+		assertEquals(ClassA.class.getName(), ClassA.returnGetCallingClass());
+		assertEquals(this.getClass().getName(), ClassB.returnGetCallingClass());
 	}
 
 	public static class ClassA {
-		static Class<?> returnGetCallingClass() {
-			return CallingClassUtils.getCallingClass();
+		static String returnGetCallingClass() {
+			return CallingClassUtils.getCallingClassName();
 		}
 	}
 
 	@IgnoreAsCallingClass
 	private static class ClassB {
-		static Class<?> returnGetCallingClass() {
-			return CallingClassUtils.getCallingClass();
+		static String returnGetCallingClass() {
+			return CallingClassUtils.getCallingClassName();
 		}
 	}
 }