hide debug info by default

Signed-off-by: pengzhile <pengzhile@gmail.com>

src/main/java/io/zhile/research/ja/netfilter/Launcher.java

@@ -20,7 +20,6 @@ public class Launcher {
         }
 
         try {
-            jarURL = new URL("file:/Users/neo/Downloads/ja-netfilter/target/ja-netfilter-jar-with-dependencies.jar");
             inst.appendToBootstrapClassLoaderSearch(new JarFile(jarURL.getPath()));
         } catch (Throwable e) {
             throw new RuntimeException("Can not access ja-netfilter jar file.", e);

src/main/java/io/zhile/research/ja/netfilter/TransformDispatcher.java

@@ -1,5 +1,6 @@
 package io.zhile.research.ja.netfilter;
 
+import io.zhile.research.ja.netfilter.commons.DebugInfo;
 import io.zhile.research.ja.netfilter.transformers.HttpClientTransformer;
 import io.zhile.research.ja.netfilter.transformers.InetAddressTransformer;
 import io.zhile.research.ja.netfilter.transformers.MyTransformer;
@@ -33,7 +34,7 @@ public class TransformDispatcher implements ClassFileTransformer {
             try {
                 return transformer.transform(className, classFileBuffer);
             } catch (Exception e) {
-                System.out.println("=== Transform class failed: " + e.getMessage());
+                DebugInfo.output("=== Transform class failed: " + e.getMessage());
             }
         } while (false);
 

src/main/java/io/zhile/research/ja/netfilter/commons/DebugInfo.java

@@ -0,0 +1,20 @@
+package io.zhile.research.ja.netfilter.commons;
+
+import io.zhile.research.ja.netfilter.utils.DateUtils;
+
+public class DebugInfo {
+    private static final boolean DEBUG = "1".equals(System.getenv("JANF_DEBUG"));
+
+    public static void output(String content) { // No logger lib required
+        if (!DEBUG) {
+            return;
+        }
+
+        String template = "[%s] %s DEBUG : %s%n";
+
+        StackTraceElement[] traces = new Throwable().getStackTrace();
+        String caller = traces.length < 2 ? "UNKNOWN" : traces[1].toString();
+
+        System.out.printf(template, DateUtils.formatNow(), caller, content);
+    }
+}

src/main/java/io/zhile/research/ja/netfilter/filters/DNSFilter.java

@@ -1,5 +1,6 @@
 package io.zhile.research.ja.netfilter.filters;
 
+import io.zhile.research.ja.netfilter.commons.DebugInfo;
 import io.zhile.research.ja.netfilter.enums.RuleType;
 import io.zhile.research.ja.netfilter.models.FilterRule;
 
@@ -26,7 +27,7 @@ public class DNSFilter {
                 continue;
             }
 
-            System.out.println("=== reject dns query: " + host + ", rule: " + rule);
+            DebugInfo.output("=== reject dns query: " + host + ", rule: " + rule);
             throw new java.net.UnknownHostException();
         }
 
@@ -43,7 +44,7 @@ public class DNSFilter {
                 continue;
             }
 
-            System.out.println("=== reject dns reachable test: " + n.getHostName() + ", rule: " + rule);
+            DebugInfo.output("=== reject dns reachable test: " + n.getHostName() + ", rule: " + rule);
             return false;
         }
 

src/main/java/io/zhile/research/ja/netfilter/filters/URLFilter.java

@@ -1,5 +1,6 @@
 package io.zhile.research.ja.netfilter.filters;
 
+import io.zhile.research.ja.netfilter.commons.DebugInfo;
 import io.zhile.research.ja.netfilter.enums.RuleType;
 import io.zhile.research.ja.netfilter.models.FilterRule;
 
@@ -27,7 +28,7 @@ public class URLFilter {
                 continue;
             }
 
-            System.out.println("=== reject url: " + url + ", rule: " + rule);
+            DebugInfo.output("=== reject url: " + url + ", rule: " + rule);
             throw new SocketTimeoutException("connect timed out");
         }
 

src/main/java/io/zhile/research/ja/netfilter/utils/DateUtils.java

@@ -0,0 +1,40 @@
+package io.zhile.research.ja.netfilter.utils;
+
+import java.text.DateFormat;
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+
+public class DateUtils {
+    public static final DateFormat FULL_DF = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
+    public static final DateFormat DATE_DF = new SimpleDateFormat("yyyy-MM-dd");
+    public static final DateFormat TIME_DF = new SimpleDateFormat("HH:mm:ss");
+
+    public static String formatDateTime(Date date) {
+        return FULL_DF.format(date);
+    }
+
+    public static String formatDate(Date date) {
+        return DATE_DF.format(date);
+    }
+
+    public static String formatTime(Date date) {
+        return TIME_DF.format(date);
+    }
+
+    public static Date parseTime(String timeStr) throws ParseException {
+        return TIME_DF.parse(timeStr);
+    }
+
+    public static Date parseDate(String dateStr) throws ParseException {
+        return DATE_DF.parse(dateStr);
+    }
+
+    public static Date parseDateTime(String dateTimeStr) throws ParseException {
+        return FULL_DF.parse(dateTimeStr);
+    }
+
+    public static String formatNow() {
+        return formatDateTime(new Date());
+    }
+}