begin working on log panel for immediate status and info reporting

src/main/java/com/mykola2312/mptv/ui/LogPanel.java

@@ -0,0 +1,74 @@
+package com.mykola2312.mptv.ui;
+
+import java.awt.BorderLayout;
+
+import javax.swing.JPanel;
+import javax.swing.JScrollPane;
+import javax.swing.JTextArea;
+import javax.swing.text.DefaultCaret;
+
+import org.apache.log4j.AppenderSkeleton;
+import org.apache.log4j.Level;
+import org.apache.log4j.Logger;
+import org.apache.log4j.spi.LoggingEvent;
+import org.apache.log4j.spi.Filter;;
+
+public class LogPanel extends JPanel {
+    private class LogAppender extends AppenderSkeleton {
+        private final LogPanel area;
+        
+        public LogAppender(LogPanel area) {
+            super();
+            this.area = area;
+            
+            this.addFilter(new Filter() {
+                @Override()
+                public int decide(LoggingEvent event) {
+                    if (event.getLevel().equals(Level.DEBUG)) {
+                        return DENY;
+                    } else {
+                        return ACCEPT;
+                    }
+                }
+            });
+        }
+
+        @Override
+        public void close() {}
+
+        @Override
+        public boolean requiresLayout() {
+            return false;
+        }
+
+        @Override
+        protected void append(LoggingEvent event) {
+            area.appendEvent(event);
+        }
+    }
+
+    private final JTextArea logArea;
+    private final JScrollPane scrollLog;
+
+    public void appendEvent(LoggingEvent event) {
+        String content = event.getRenderedMessage();
+        logArea.append(content + "\n");
+        logArea.setCaretPosition(logArea.getDocument().getLength());
+    }
+
+    public LogPanel(Logger target) {
+        super(new BorderLayout());
+        
+        logArea = new JTextArea();
+        logArea.setEditable(false);
+        DefaultCaret caret = (DefaultCaret) logArea.getCaret();
+        caret.setUpdatePolicy(DefaultCaret.OUT_BOTTOM);
+
+        scrollLog = new JScrollPane(logArea);
+        scrollLog.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_NEVER);
+        scrollLog.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
+        add(scrollLog, BorderLayout.CENTER);
+
+        target.addAppender(new LogAppender(this));
+    }
+}