[LOGBACK-540] Filtering out selected stack trace frames

logback-classic/src/main/java/ch/qos/logback/classic/pattern/ThrowableProxyConverter.java

@@ -38,6 +38,7 @@ public class ThrowableProxyConverter extends ThrowableHandlingConverter {
 
   int lengthOption;
   List<EventEvaluator<ILoggingEvent>> evaluatorList = null;
+  List<String> ignoredStackTraceLines = null;
 
   int errorCount = 0;
 
@@ -69,12 +70,16 @@ public void start() {
     if (optionList != null && optionList.size() > 1) {
       final int optionListSize = optionList.size();
       for (int i = 1; i < optionListSize; i++) {
-        String evaluatorStr = (String) optionList.get(i);
+        String evaluatorOrIgnoredStackTraceLine = (String) optionList.get(i);
         Context context = getContext();
         Map evaluatorMap = (Map) context.getObject(CoreConstants.EVALUATOR_MAP);
         EventEvaluator<ILoggingEvent> ee = (EventEvaluator<ILoggingEvent>) evaluatorMap
-                .get(evaluatorStr);
-        addEvaluator(ee);
+                .get(evaluatorOrIgnoredStackTraceLine);
+        if (ee != null) {
+          addEvaluator(ee);
+        } else {
+          addIgnoreStackTraceLine(evaluatorOrIgnoredStackTraceLine);
+        }
       }
     }
     super.start();
@@ -87,6 +92,13 @@ private void addEvaluator(EventEvaluator<ILoggingEvent> ee) {
     evaluatorList.add(ee);
   }
 
+  private void addIgnoreStackTraceLine(String ignoredStackTraceLine) {
+    if (ignoredStackTraceLines == null) {
+      ignoredStackTraceLines = new ArrayList<String>();
+    }
+    ignoredStackTraceLines.add(ignoredStackTraceLine);
+  }
+
   public void stop() {
     evaluatorList = null;
     super.stop();
@@ -185,10 +197,23 @@ protected void subjoinSTEPArray(StringBuilder buf, int indent, IThrowableProxy t
       maxIndex -= commonFrames;
     }
 
+    int ignoredCount = 0;
     for (int i = 0; i < maxIndex; i++) {
-      ThrowableProxyUtil.indent(buf, indent);
-      buf.append(stepArray[i]);
-      extraData(buf, stepArray[i]); // allow other data to be added
+      StackTraceElementProxy element = stepArray[i];
+      if (!isIgnoredStackTraceLine(element.toString())) {
+        ThrowableProxyUtil.indent(buf, indent);
+        printStackLine(buf, ignoredCount, element);
+        ignoredCount = 0;
+        buf.append(CoreConstants.LINE_SEPARATOR);
+      } else {
+        ++ignoredCount;
+        if (maxIndex < stepArray.length) {
+          ++maxIndex;
+        }
+      }
+    }
+    if (ignoredCount > 0) {
+      printIgnoredCount(buf, ignoredCount);
       buf.append(CoreConstants.LINE_SEPARATOR);
     }
 
@@ -198,4 +223,28 @@ protected void subjoinSTEPArray(StringBuilder buf, int indent, IThrowableProxy t
               " common frames omitted").append(CoreConstants.LINE_SEPARATOR);
     }
   }
+
+  private void printStackLine(StringBuilder buf, int ignoredCount, StackTraceElementProxy element) {
+    buf.append(element);
+    extraData(buf, element); // allow other data to be added
+    if (ignoredCount > 0) {
+      printIgnoredCount(buf, ignoredCount);
+    }
+  }
+
+  private void printIgnoredCount(StringBuilder buf, int ignoredCount) {
+    buf.append(" [").append(ignoredCount).append(" skipped]");
+  }
+
+  private boolean isIgnoredStackTraceLine(String line) {
+    if (ignoredStackTraceLines != null) {
+      for (String ignoredStackTraceLine : ignoredStackTraceLines) {
+        if (line.contains(ignoredStackTraceLine)) {
+          return true;
+        }
+      }
+    }
+    return false;
+  }
+
 }

logback-classic/src/test/java/ch/qos/logback/classic/pattern/ThrowableProxyConverterTest.java

@@ -21,6 +21,7 @@
 import java.util.Arrays;
 import java.util.List;
 
+import ch.qos.logback.core.CoreConstants;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -33,6 +34,7 @@
 import ch.qos.logback.classic.util.TeztHelper;
 
 import static ch.qos.logback.classic.util.TeztHelper.addSuppressed;
+import static org.fest.assertions.Assertions.assertThat;
 import static org.junit.Assert.*;
 import static org.junit.Assume.assumeTrue;
 
@@ -158,6 +160,57 @@ public void withShortArgument() throws Exception {
     assertNull("Unexpected line in stack trace", reader.readLine());
   }
 
+  @Test
+  public void skipSelectedLine() throws Exception {
+    //given
+    final Throwable t = TeztHelper.makeNestedException(0);
+    t.printStackTrace(pw);
+    final ILoggingEvent le = createLoggingEvent(t);
+    tpc.setOptionList(Arrays.asList("full", "skipSelectedLines"));
+    tpc.start();
+
+    //when
+    final String result = tpc.convert(le);
+
+    //then
+    assertThat(result).excludes("skipSelectedLines");
+  }
+
+  @Test
+  public void skipMultipleLines() throws Exception {
+    //given
+    final Throwable t = TeztHelper.makeNestedException(0);
+    t.printStackTrace(pw);
+    final ILoggingEvent le = createLoggingEvent(t);
+    tpc.setOptionList(Arrays.asList("full", "skipMultipleLines", "junit"));
+    tpc.start();
+
+    //when
+    final String result = tpc.convert(le);
+
+    //then
+    assertThat(result)
+        .excludes("skipSelectedLines")
+        .excludes("junit");
+  }
+
+  @Test
+  public void shouldLimitTotalLinesExcludingSkipped() throws Exception {
+    //given
+    final Throwable t = TeztHelper.makeNestedException(0);
+    t.printStackTrace(pw);
+    final ILoggingEvent le = createLoggingEvent(t);
+    tpc.setOptionList(Arrays.asList("3", "shouldLimitTotalLinesExcludingSkipped"));
+    tpc.start();
+
+    //when
+    final String result = tpc.convert(le);
+
+    //then
+    String[] lines = result.split(CoreConstants.LINE_SEPARATOR);
+    assertThat(lines).hasSize(3 + 1);
+  }
+
   void someMethod() throws Exception {
     throw new Exception("someMethod");
   }