provide framework for application logging

src/main/java/com/sparrowwallet/drongo/ApplicationAppender.java

@@ -0,0 +1,20 @@
+package com.sparrowwallet.drongo;
+
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.AppenderBase;
+import org.slf4j.event.Level;
+
+import java.lang.reflect.InvocationTargetException;
+
+public class ApplicationAppender extends AppenderBase<ILoggingEvent> {
+    private LogHandler callback;
+
+    @Override
+    protected void append(ILoggingEvent e) {
+        callback.handleLog(e.getThreadName(), Level.valueOf(e.getLevel().toString()), e.getMessage(), e.getLoggerName(), e.getTimeStamp(), e.getCallerData());
+    }
+
+    public void setCallback(String callback) throws ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InvocationTargetException, InstantiationException {
+        this.callback = (LogHandler)Class.forName(callback).getConstructor().newInstance();
+    }
+}

src/main/java/com/sparrowwallet/drongo/LogHandler.java

@@ -0,0 +1,7 @@
+package com.sparrowwallet.drongo;
+
+import org.slf4j.event.Level;
+
+public interface LogHandler {
+    void handleLog(String threadName, Level level, String message, String loggerName, long timestamp, StackTraceElement[] callerData);
+}