Pushing commit for BAEL-4999

logging-modules/logback/src/main/java/com/baeldung/logback/MaskingPatternLayout.java

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+package com.baeldung.logback;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+import ch.qos.logback.classic.PatternLayout;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+
+public class MaskingPatternLayout extends PatternLayout {
+
+    private Pattern multilinePattern;
+    private List<String> maskPatterns = new ArrayList<>();
+
+    // invoked for every single entry in the xml
+    public void addMaskPattern(String maskPattern) {
+        maskPatterns.add(maskPattern);
+        multilinePattern = Pattern.compile(maskPatterns.stream().collect(Collectors.joining("|")), Pattern.MULTILINE);
+    }
+
+    @Override
+    public String doLayout(ILoggingEvent event) {
+        return maskMessage(super.doLayout(event));
+    }
+
+    private String maskMessage(String message) {
+        if (multilinePattern == null) {
+            return message;
+        }
+        StringBuilder sb = new StringBuilder(message);
+        Matcher matcher = multilinePattern.matcher(sb);
+        while (matcher.find()) {
+            IntStream.rangeClosed(1, matcher.groupCount()).forEach(group -> {
+                if (matcher.group(group) != null) {
+                    // replace each character with asterisk
+                    IntStream.range(matcher.start(group), matcher.end(group)).forEach(i -> sb.setCharAt(i, '*'));
+                }
+            });
+        }
+        return sb.toString();
+    }
+
+}

logging-modules/logback/src/main/java/com/baeldung/logback/MaskingPatternLayoutExample.java

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+package com.baeldung.logback;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.json.JSONObject;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class MaskingPatternLayoutExample {
+
+    private static final Logger logger = LoggerFactory.getLogger(MaskingPatternLayoutExample.class);
+
+    public static void main(String[] args) {
+        Map<String, String> user = new HashMap<String, String>();
+        user.put("user_id", "87656");
+        user.put("SSN", "786445563");
+        user.put("address", "22 Street");
+        user.put("city", "Chicago");
+        user.put("Country", "U.S.");
+        user.put("ip_address", "192.168.1.1");
+        user.put("email_id", "spring@baeldung.com");
+        JSONObject userDetails = new JSONObject(user);
+
+        logger.info("MaskingPatternExample log from {}" + userDetails,
+                MaskingPatternLayoutExample.class.getSimpleName());
+    }
+}