StringFormatter: fix exception format

src/main/java/io/gitlab/jfronny/commons/StringFormatter.java

@@ -1,7 +1,7 @@
 package io.gitlab.jfronny.commons;
 
-import java.io.*;
-import java.util.Locale;
+import java.util.*;
+import java.util.function.Function;
 
 public class StringFormatter {
     public static String toString(Object o) {
@@ -11,20 +11,47 @@ public class StringFormatter {
             else if (d > 1) return String.format(Locale.US, "%.4f", d);
             else return String.format(Locale.US, "%s", d);
         } else if (o instanceof Throwable t) {
-            try {
-                return t.getMessage() + getStackTrace(t);
-            } catch (IOException e) {
-                return t.toString();
-            }
+            return toString(t, Objects::toString);
         } else return o.toString();
     }
 
-    public static String getStackTrace(Throwable t) throws IOException {
-        try (ByteArrayOutputStream baot = new ByteArrayOutputStream()) {
-            try (PrintStream ps = new PrintStream(baot, true)) {
-                t.printStackTrace(ps);
-            }
-            return baot.toString();
+    public static String toString(Throwable t, Function<Throwable, String> stringify) {
+        return stringify.apply(t) + "\n" + getStackTrace(t, stringify);
+    }
+
+    public static String getStackTrace(Throwable t) {
+        return getStackTrace(t, Objects::toString);
+    }
+
+    public static String getStackTrace(Throwable t, Function<Throwable, String> stringify) {
+        StringBuilder sb = new StringBuilder();
+        getStackTrace(sb, t, new StackTraceElement[0], "", "", Objects.requireNonNull(stringify), new HashSet<>(), true);
+        return sb.toString();
+    }
+
+    private static void getStackTrace(StringBuilder sb, Throwable t, StackTraceElement[] enclosingTrace, String caption, String prefix, Function<Throwable, String> stringify, Set<Throwable> dejaVu, boolean skipHeader) {
+        if (!skipHeader) sb.append(prefix).append(caption);
+
+        if (!dejaVu.add(t)) {
+            sb.append("[CIRCULAR REFERENCE: ").append(stringify.apply(t)).append("]\n");
+            return;
         }
+
+        StackTraceElement[] trace = t.getStackTrace();
+        int m = trace.length - 1;
+        int n = enclosingTrace.length - 1;
+        while (m >= 0 && n >= 0 && trace[m].equals(enclosingTrace[n])) {
+            m--; n--;
+        }
+        int framesInCommon = trace.length - 1 - m;
+
+        if (!skipHeader) sb.append(stringify.apply(t)).append('\n');
+        for (int i = 0; i <= m; i++) sb.append(prefix).append("\tat ").append(trace[i]).append('\n');
+        if (framesInCommon != 0) sb.append(prefix).append("\t... ").append(framesInCommon).append(" more").append('\n');
+        for (Throwable se : t.getSuppressed()) {
+            getStackTrace(sb, se, trace, "Suppressed: ", prefix + "\t", stringify, dejaVu, false);
+        }
+        Throwable cause = t.getCause();
+        if (cause != null) getStackTrace(sb, cause, trace, "Caused by: ", prefix, stringify, dejaVu, false);
     }
 }