strip leading and trailing, but do not squash inner whitespaces (#100)

src/main/java/de/siegmar/logbackgelf/GelfEncoder.java

@@ -438,34 +438,12 @@ protected String normalizeShortMessage(final String shortMessage) {
         return sanitizedShortMessage;
     }
 
-    private String sanitizeShortMessage(final String sanitizedShortMessage) {
-        if (sanitizedShortMessage.isEmpty()) {
-            return sanitizedShortMessage;
+    private String sanitizeShortMessage(final String shortMessage) {
+        String sanitized = shortMessage.stripLeading();
+        if (getMaxShortMessageLength() != 0 && sanitized.length() > getMaxShortMessageLength()) {
+            sanitized = sanitized.substring(0, getMaxShortMessageLength());
         }
-
-        final int len = maxShortMessageLength == 0
-            ? sanitizedShortMessage.length()
-            : Math.min(sanitizedShortMessage.length(), maxShortMessageLength);
-        final char[] tmp = new char[len];
-
-        int iDst = 0;
-        boolean whitspaceLast = false;
-        boolean whitespaceStart = true;
-        for (int iSrc = 0; iSrc < sanitizedShortMessage.length() && iDst < tmp.length; iSrc++) {
-            final char c = sanitizedShortMessage.charAt(iSrc);
-            if (Character.isWhitespace(c)) {
-                if (!whitespaceStart && !whitspaceLast) {
-                    tmp[iDst++] = ' ';
-                }
-                whitspaceLast = true;
-            } else {
-                tmp[iDst++] = c;
-                whitspaceLast = false;
-                whitespaceStart = false;
-            }
-        }
-
-        return new String(tmp, 0, iDst).trim();
+        return sanitized.stripTrailing();
     }
 
     protected String buildShortMessage(final ILoggingEvent event) {

src/test/java/de/siegmar/logbackgelf/GelfEncoderTest.java

@@ -134,6 +134,58 @@ void shortenShortMessageDefault() {
             .isEqualTo(expectedShortMessage);
     }
 
+    @Test
+    void doNotSquashInnerWhitespaces() {
+        final String shortMessage = "unknown operand:\nx=1 § 1\n    ^";
+
+        final GelfEncoder gelfEncoder = new GelfEncoder();
+
+        final String actual = gelfEncoder.normalizeShortMessage(shortMessage);
+        assertThat(actual).isEqualTo(shortMessage);
+    }
+
+    @Test
+    void stripLeadingAndTrailingWhitespaces() {
+        final String shortMessage = "\t [---] \n";
+
+        final GelfEncoder gelfEncoder = new GelfEncoder();
+
+        final String actual = gelfEncoder.normalizeShortMessage(shortMessage);
+        assertThat(actual).isEqualTo("[---]");
+    }
+
+    @Test
+    void stripTrailingWhitespacesAfterTrimming() {
+        final String shortMessage = "a          b";
+
+        final GelfEncoder gelfEncoder = new GelfEncoder();
+        gelfEncoder.setMaxShortMessageLength(5);
+
+        final String actual = gelfEncoder.normalizeShortMessage(shortMessage);
+        assertThat(actual).isEqualTo("a");
+    }
+
+    @Test
+    void maxMessageLengthSetAndMessageIsShorter() {
+        final String shortMessage = "abc";
+
+        final GelfEncoder gelfEncoder = new GelfEncoder();
+        gelfEncoder.setMaxShortMessageLength(5);
+
+        final String actual = gelfEncoder.normalizeShortMessage(shortMessage);
+        assertThat(actual).isEqualTo("abc");
+    }
+
+    @Test
+    void shortenAfterStrippingWhitespaces() {
+        final String shortMessage = "\t \n" + "A".repeat(250) + "\t \n";
+
+        final GelfEncoder gelfEncoder = new GelfEncoder();
+
+        final String actual = gelfEncoder.normalizeShortMessage(shortMessage);
+        assertThat(actual).hasSize(250).doesNotContainAnyWhitespaces();
+    }
+
     @Test
     void exception() {
         encoder.start();