add debug logging with slf4j.Logger for mvn -X

allow e.g. maven (which also uses Slf4j) to see / capture resolver debug log output e.g. when running mvn -X clean install

Signed-off-by: Christoph Rueger <[email protected]>

biz.aQute.resolve/src/biz/aQute/resolve/ResolverLogger.java

@@ -10,6 +10,8 @@
 
 import org.osgi.framework.ServiceReference;
 import org.osgi.service.log.LogService;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import aQute.bnd.exceptions.Exceptions;
 import aQute.bnd.osgi.Constants;
@@ -19,6 +21,8 @@
 
 public class ResolverLogger implements LogService, AutoCloseable {
 
+	private static final Logger	logger			= LoggerFactory.getLogger(ResolverLogger.class);
+
 	public static final int		DEFAULT_LEVEL	= 4;
 
 	public static final int		LOG_ERROR		= 1;
@@ -56,6 +60,7 @@ public ResolverLogger(int level, PrintStream out) {
 		printer = IO.writer(out, UTF_8);
 	}
 
+
 	@Override
 	public void log(int level, String msg, Throwable throwable) {
 		switch (level) {
@@ -68,6 +73,7 @@ public void log(int level, String msg, Throwable throwable) {
 				printLog(msg, throwable);
 				if (throwable != null) {
 					throwable.printStackTrace(printer);
+					logger.debug("", throwable);
 				}
 				break;
 			case LOG_INFO :
@@ -91,10 +97,13 @@ public void log(int level, String msg, Throwable throwable) {
 
 	private void printLog(String msg, Throwable throwable) {
 		printer.print(msg);
+		logger.debug(msg);
 		if (throwable != null) {
 			printer.print(" (");
 			printer.print(throwable);
 			printer.print(")");
+
+			logger.debug("({})", String.valueOf(throwable));
 		}
 		printer.println();
 	}
@@ -203,7 +212,7 @@ public static ResolverLogger newLogger(Processor processor, boolean keepLogFileT
 				logger.setKeepLogFileTillExit(keepLogFileTillJvmExit);
 				return logger;
 			}
-			ResolverLogger logger = new ResolverLogger();
+			ResolverLogger logger = new ResolverLogger(DEFAULT_LEVEL);
 			logger.setKeepLogFileTillExit(keepLogFileTillJvmExit);
 			return logger;
 		} catch (Exception e) {