Using constants to avoid the use of hardcoded values

src/main/java/dev/toonformat/jtoon/decoder/ArrayDecoder.java

@@ -7,6 +7,10 @@
 import java.util.List;
 import java.util.regex.Matcher;
 
+import static dev.toonformat.jtoon.util.Constants.BACKSLASH;
+import static dev.toonformat.jtoon.util.Constants.COLON;
+import static dev.toonformat.jtoon.util.Constants.DOUBLE_QUOTE;
+import static dev.toonformat.jtoon.util.Constants.LIST_ITEM_PREFIX;
 import static dev.toonformat.jtoon.util.Headers.ARRAY_HEADER_PATTERN;
 import static dev.toonformat.jtoon.util.Headers.TABULAR_HEADER_PATTERN;
 
@@ -47,10 +51,10 @@ static Delimiter extractDelimiterFromHeader(String header, DecodeContext context
         if (matcher.find()) {
             String delimiter = matcher.group(3);
             if (delimiter != null) {
-                if ("\t".equals(delimiter)) {
+                if (Delimiter.TAB.toString().equals(delimiter)) {
                     return Delimiter.TAB;
                 }
-                if ("|".equals(delimiter)) {
+                if (Delimiter.PIPE.toString().equals(delimiter)) {
                     return Delimiter.PIPE;
                 }
             }
@@ -82,7 +86,7 @@ static List<Object> parseArrayWithDelimiter(String header, int depth, Delimiter
             int headerEndIdx = arrayMatcher.end();
             String afterHeader = header.substring(headerEndIdx).trim();
 
-            if (afterHeader.startsWith(":")) {
+            if (afterHeader.startsWith(COLON)) {
                 String inlineContent = afterHeader.substring(1).trim();
 
                 if (!inlineContent.isEmpty()) {
@@ -106,7 +110,7 @@ static List<Object> parseArrayWithDelimiter(String header, int depth, Delimiter
                     return Collections.emptyList();
                 }
 
-                if (nextContent.startsWith("- ")) {
+                if (nextContent.startsWith(LIST_ITEM_PREFIX)) {
                     context.currentLine--;
                     return parseListArray(depth, header, context);
                 } else {
@@ -195,11 +199,11 @@ static List<String> parseDelimitedValues(String input, Delimiter arrayDelimiter)
                 stringBuilder.append(currentChar);
                 escaped = false;
                 i++;
-            } else if (currentChar == '\\') {
+            } else if (currentChar == BACKSLASH) {
                 stringBuilder.append(currentChar);
                 escaped = true;
                 i++;
-            } else if (currentChar == '"') {
+            } else if (currentChar == DOUBLE_QUOTE) {
                 stringBuilder.append(currentChar);
                 inQuotes = !inQuotes;
                 i++;

src/main/java/dev/toonformat/jtoon/decoder/DecodeHelper.java

@@ -5,6 +5,11 @@
 import java.util.List;
 import java.util.Map;
 
+import static dev.toonformat.jtoon.util.Constants.BACKSLASH;
+import static dev.toonformat.jtoon.util.Constants.DOUBLE_QUOTE;
+import static dev.toonformat.jtoon.util.Constants.SPACE;
+import static dev.toonformat.jtoon.util.Constants.COLON;
+
 /**
  * Handles indentation, depth, conflicts, and validation for other decode classes.
  */
@@ -47,7 +52,7 @@ private static int computeLeadingSpaces(String line, DecodeContext context) {
         int lengthOfLine = line.length();
         while (i < lengthOfLine) {
             char c = line.charAt(i);
-            if (c == ' ') {
+            if (c == SPACE.charAt(0)) {
                 leadingSpaces++;
             } else if (c == Delimiter.TAB.getValue()) {
                 if (context.options.strict()) {
@@ -98,11 +103,11 @@ static int findUnquotedColon(String content) {
 
             if (escaped) {
                 escaped = false;
-            } else if (c == '\\') {
+            } else if (c == BACKSLASH) {
                 escaped = true;
-            } else if (c == '"') {
+            } else if (c == DOUBLE_QUOTE) {
                 inQuotes = !inQuotes;
-            } else if (c == ':' && !inQuotes) {
+            } else if (c == COLON.charAt(0) && !inQuotes) {
                 return i;
             }
         }

src/main/java/dev/toonformat/jtoon/decoder/KeyDecoder.java

@@ -9,6 +9,7 @@
 import java.util.Map;
 import java.util.regex.Matcher;
 
+import static dev.toonformat.jtoon.util.Constants.DOT;
 import static dev.toonformat.jtoon.util.Headers.KEYED_ARRAY_PATTERN;
 
 /**
@@ -156,7 +157,7 @@ static boolean shouldExpandKey(String key, DecodeContext context) {
             return false;
         }
         // Check if a key contains dots and is a valid identifier pattern
-        if (!key.contains(".")) {
+        if (!key.contains(DOT)) {
             return false;
         }
         // Valid identifier: starts with a letter or underscore, followed by letters,

src/main/java/dev/toonformat/jtoon/decoder/ListItemDecoder.java

@@ -8,6 +8,8 @@
 import java.util.Map;
 import java.util.regex.Matcher;
 
+import static dev.toonformat.jtoon.util.Constants.LIST_ITEM_MARKER;
+import static dev.toonformat.jtoon.util.Constants.OPEN_BRACKET;
 import static dev.toonformat.jtoon.util.Headers.KEYED_ARRAY_PATTERN;
 
 /**
@@ -31,7 +33,7 @@ public static void processListArrayItem(String line, int lineDepth, int depth,
         if (lineDepth == depth + 1) {
             String content = line.substring((depth + 1) * context.options.indent());
 
-            if (content.startsWith("-")) {
+            if (content.startsWith(LIST_ITEM_MARKER)) {
                 result.add(parseListItem(content, depth, context));
             } else {
                 context.currentLine++;
@@ -66,7 +68,7 @@ public static Object parseListItem(String content, int depth, DecodeContext cont
         }
 
         // Check for standalone array (e.g., "[2]: 1,2")
-        if (itemContent.startsWith("[")) {
+        if (itemContent.startsWith(OPEN_BRACKET)) {
             // For nested arrays in list items, default to comma delimiter if not specified
             Delimiter nestedArrayDelimiter = ArrayDecoder.extractDelimiterFromHeader(itemContent, context);
             // parseArrayWithDelimiter handles currentLine increment internally

src/main/java/dev/toonformat/jtoon/decoder/PrimitiveDecoder.java

@@ -2,6 +2,11 @@
 
 import dev.toonformat.jtoon.util.StringEscaper;
 
+import static dev.toonformat.jtoon.util.Constants.DOT;
+import static dev.toonformat.jtoon.util.Constants.NULL_LITERAL;
+import static dev.toonformat.jtoon.util.Constants.TRUE_LITERAL;
+import static dev.toonformat.jtoon.util.Constants.FALSE_LITERAL;
+
 /**
  * Handles parsing of primitive TOON values with type inference.
  *
@@ -48,13 +53,13 @@ static Object parse(String value) {
 
         // Check for null literal
         switch (value) {
-            case "null" -> {
+            case NULL_LITERAL -> {
                 return null;
             }
-            case "true" -> {
+            case TRUE_LITERAL -> {
                 return true;
             }
-            case "false" -> {
+            case FALSE_LITERAL -> {
                 return false;
             }
             default -> {
@@ -78,7 +83,7 @@ static Object parse(String value) {
         // Try parsing as number
         try {
             // Check if it contains exponent notation or decimal point
-            if (value.contains(".") || value.contains("e") || value.contains("E")) {
+            if (value.contains(DOT) || value.contains("e") || value.contains("E")) {
                 double parsed = Double.parseDouble(value);
                 // Handle negative zero - Java doesn't distinguish, but spec says it should be 0
                 if (parsed == 0.0) {

src/main/java/dev/toonformat/jtoon/decoder/TabularArrayDecoder.java

@@ -10,6 +10,8 @@
 import java.util.Map;
 import java.util.regex.Matcher;
 
+import static dev.toonformat.jtoon.util.Constants.BACKSLASH;
+import static dev.toonformat.jtoon.util.Constants.DOUBLE_QUOTE;
 import static dev.toonformat.jtoon.util.Headers.TABULAR_HEADER_PATTERN;
 
 /**
@@ -101,9 +103,9 @@ private static void validateKeysDelimiter(String keysStr, Delimiter expectedDeli
             char c = keysStr.charAt(i);
             if (escaped) {
                 escaped = false;
-            } else if (c == '\\') {
+            } else if (c == BACKSLASH) {
                 escaped = true;
-            } else if (c == '"') {
+            } else if (c == DOUBLE_QUOTE) {
                 inQuotes = !inQuotes;
             } else if (!inQuotes) {
                 checkDelimiterMismatch(expectedChar, c);

src/main/java/dev/toonformat/jtoon/decoder/ValueDecoder.java

@@ -7,6 +7,8 @@
 import java.util.LinkedHashMap;
 import java.util.regex.Matcher;
 
+import static dev.toonformat.jtoon.util.Constants.NULL_LITERAL;
+import static dev.toonformat.jtoon.util.Constants.OPEN_BRACKET;
 import static dev.toonformat.jtoon.util.Headers.KEYED_ARRAY_PATTERN;
 
 /**
@@ -52,7 +54,7 @@ public static Object decode(String toon, DecodeOptions options) {
 
         // Special case: if input is exactly "null", return null
         String trimmed = toon.trim();
-        if ("null".equals(trimmed)) {
+        if (NULL_LITERAL.equals(trimmed)) {
             return null;
         }
 
@@ -78,7 +80,7 @@ public static Object decode(String toon, DecodeOptions options) {
         }
 
         // Handle standalone arrays: [2]:
-        if (!line.isEmpty() && line.charAt(0) == '[') {
+        if (!line.isEmpty() && line.charAt(0) == OPEN_BRACKET.charAt(0)) {
             return ArrayDecoder.parseArray(line, depth, context);
         }
 

src/main/java/dev/toonformat/jtoon/encoder/ArrayEncoder.java

@@ -1,6 +1,5 @@
 package dev.toonformat.jtoon.encoder;
 
-
 import dev.toonformat.jtoon.EncodeOptions;
 import tools.jackson.databind.JsonNode;
 import tools.jackson.databind.node.ArrayNode;

src/main/java/dev/toonformat/jtoon/encoder/Flatten.java

@@ -10,6 +10,8 @@
 import java.util.Set;
 import java.util.regex.Pattern;
 
+import static dev.toonformat.jtoon.util.Constants.DOT;
+
 /**
  * Recursively flattens a JSON object or array into a single-level object.
  */
@@ -75,7 +77,7 @@ public static FoldResult tryFoldKeyChain(String key,
         }
 
         // start chain from absolute key
-        String absKey = (pathPrefix == null) ? key : String.join(".", pathPrefix, key);
+        String absKey = (pathPrefix == null) ? key : String.join(DOT, pathPrefix, key);
 
         // Collect segments of the single-key chain
         final ChainResult chain = collectSingleKeyChain(absKey, value, remainingDepth);
@@ -97,7 +99,7 @@ public static FoldResult tryFoldKeyChain(String key,
         }
 
         // Build folded key
-        String foldedKey = String.join(".", chain.segments);
+        String foldedKey = String.join(DOT, chain.segments);
 
         // Detect collisions with sibling keys
         if (siblings.contains(foldedKey)) {
@@ -107,7 +109,7 @@ public static FoldResult tryFoldKeyChain(String key,
         // Compute absolute dotted path
         String absolutePath =
                 (pathPrefix != null && !pathPrefix.isEmpty())
-                        ? String.join(".", pathPrefix, foldedKey)
+                        ? String.join(DOT, pathPrefix, foldedKey)
                         : foldedKey;
 
 
@@ -138,8 +140,8 @@ public static FoldResult tryFoldKeyChain(String key,
      */
     private static ChainResult collectSingleKeyChain(String startKey, JsonNode startValue, int maxDepth) {
         // normalize absolute key to its local segment
-        String localStartKey = startKey.contains(".")
-                ? startKey.substring(startKey.lastIndexOf('.') + 1)
+        String localStartKey = startKey.contains(DOT)
+                ? startKey.substring(startKey.lastIndexOf(DOT.charAt(0)) + 1)
                 : startKey;
 
         final List<String> segments = new ArrayList<>();

src/main/java/dev/toonformat/jtoon/encoder/HeaderFormatter.java

@@ -2,7 +2,13 @@
 
 import java.util.List;
 
-import static dev.toonformat.jtoon.util.Constants.*;
+import static dev.toonformat.jtoon.util.Constants.COLON;
+import static dev.toonformat.jtoon.util.Constants.OPEN_BRACKET;
+import static dev.toonformat.jtoon.util.Constants.COMMA;
+import static dev.toonformat.jtoon.util.Constants.OPEN_BRACE;
+import static dev.toonformat.jtoon.util.Constants.CLOSE_BRACE;
+import static dev.toonformat.jtoon.util.Constants.CLOSE_BRACKET;
+import static dev.toonformat.jtoon.util.Constants.HASHTAG;
 
 /**
  * Formats headers for arrays and tables in TOON format.
@@ -81,7 +87,7 @@ private static void appendArrayLength(
         header.append(OPEN_BRACKET);
 
         if (lengthMarker) {
-            header.append("#");
+            header.append(HASHTAG);
         }
 
         header.append(length);

src/main/java/dev/toonformat/jtoon/encoder/LineWriter.java

@@ -3,6 +3,8 @@
 import java.util.ArrayList;
 import java.util.List;
 
+import static dev.toonformat.jtoon.util.Constants.SPACE;
+
 /**
  * Line writer that accumulates indented lines for building the final output.
  */
@@ -16,7 +18,7 @@ public final class LineWriter {
      * @param indentSize Number of spaces per indentation level
      */
     public LineWriter(int indentSize) {
-        this.indentationString = " ".repeat(indentSize);
+        this.indentationString = SPACE.repeat(indentSize);
     }
 
     /**

src/main/java/dev/toonformat/jtoon/encoder/ListItemEncoder.java

@@ -10,7 +10,12 @@
 import java.util.List;
 import java.util.Set;
 
-import static dev.toonformat.jtoon.util.Constants.*;
+import static dev.toonformat.jtoon.util.Constants.LIST_ITEM_MARKER;
+import static dev.toonformat.jtoon.util.Constants.COLON;
+import static dev.toonformat.jtoon.util.Constants.SPACE;
+import static dev.toonformat.jtoon.util.Constants.LIST_ITEM_PREFIX;
+import static dev.toonformat.jtoon.util.Constants.OPEN_BRACKET;
+import static dev.toonformat.jtoon.util.Constants.CLOSE_BRACKET;
 
 /**
  * Handles encoding of objects as list items in non-uniform arrays.

src/main/java/dev/toonformat/jtoon/encoder/ObjectEncoder.java

@@ -12,6 +12,7 @@
 import java.util.Set;
 import java.util.stream.Collectors;
 
+import static dev.toonformat.jtoon.util.Constants.DOT;
 import static dev.toonformat.jtoon.util.Constants.COLON;
 import static dev.toonformat.jtoon.util.Constants.SPACE;
 
@@ -44,7 +45,7 @@ public static void encodeObject(ObjectNode value, LineWriter writer, int depth,
         if (depth == 0 && rootLiteralKeys != null) {
             rootLiteralKeys.clear();
             fields.stream()
-                .filter(e -> e.getKey().contains("."))
+                .filter(e -> e.getKey().contains(DOT))
                 .map(Map.Entry::getKey)
                 .forEach(rootLiteralKeys::add);
         }
@@ -89,7 +90,7 @@ public static void encodeKeyValuePair(String key,
             return;
         }
         String encodedKey = PrimitiveEncoder.encodeKey(key);
-        String currentPath = pathPrefix != null ? pathPrefix + "." + key : key;
+        String currentPath = pathPrefix != null ? pathPrefix + DOT + key : key;
         int effectiveFlattenDepth = flattenDepth != null && flattenDepth > 0 ? flattenDepth : options.flattenDepth();
         int remainingDepth = effectiveFlattenDepth - depth;
 
@@ -156,9 +157,9 @@ private static EncodeOptions flatten(String key, Flatten.FoldResult foldResult,
 
         // Case 2: Partially folded with a tail object
         if (remainder.isObject()) {
-            writer.push(depth, indentedLine(depth, encodedFoldedKey + ":", options.indent()));
+            writer.push(depth, indentedLine(depth, encodedFoldedKey + COLON, options.indent()));
 
-            String foldedPath = pathPrefix != null ? String.join(".", pathPrefix, foldedKey) : foldedKey;
+            String foldedPath = pathPrefix != null ? String.join(DOT, pathPrefix, foldedKey) : foldedKey;
             int newRemainingDepth = remainingDepth - foldResult.segmentCount();
 
             if (newRemainingDepth <= 0) {
@@ -182,7 +183,7 @@ private static void handleFullyFoldedLeaf(Flatten.FoldResult foldResult, LineWri
         if (leaf.isValueNode()) {
             writer.push(depth,
                 indentedLine(depth,
-                    encodedFoldedKey + ": " +
+                    encodedFoldedKey + COLON + SPACE +
                         PrimitiveEncoder.encodePrimitive(leaf, options.delimiter().toString()),
                     options.indent()));
             return;
@@ -196,7 +197,7 @@ private static void handleFullyFoldedLeaf(Flatten.FoldResult foldResult, LineWri
 
         // Object
         if (leaf.isObject()) {
-            writer.push(depth, indentedLine(depth, encodedFoldedKey + ":", options.indent()));
+            writer.push(depth, indentedLine(depth, encodedFoldedKey + COLON, options.indent()));
             if (!leaf.isEmpty()) {
                 encodeObject((ObjectNode) leaf, writer, depth + 1, options,
                     null, null, null, null);

src/main/java/dev/toonformat/jtoon/encoder/PrimitiveEncoder.java

@@ -8,7 +8,8 @@
 import java.util.List;
 import java.util.Objects;
 
-import static dev.toonformat.jtoon.util.Constants.*;
+import static dev.toonformat.jtoon.util.Constants.NULL_LITERAL;
+import static dev.toonformat.jtoon.util.Constants.DOUBLE_QUOTE;
 
 /**
  * Encodes primitive values and object keys for TOON format.