Adding a comparator to sort keys in options

config/src/main/java/com/typesafe/config/ConfigRenderOptions.java

@@ -3,6 +3,9 @@
  */
 package com.typesafe.config;
 
+import java.io.Serializable;
+import java.util.Comparator;
+
 /**
  * <p>
  * A set of options related to rendering a {@link ConfigValue}. Passed to
@@ -21,13 +24,15 @@ public final class ConfigRenderOptions {
     private final boolean comments;
     private final boolean formatted;
     private final boolean json;
+    private final Comparator<String> comparator;
 
     private ConfigRenderOptions(boolean originComments, boolean comments, boolean formatted,
-            boolean json) {
+            boolean json, Comparator<String> comparator) {
         this.originComments = originComments;
         this.comments = comments;
         this.formatted = formatted;
         this.json = json;
+        this.comparator = comparator;
     }
 
     /**
@@ -38,7 +43,7 @@ public final class ConfigRenderOptions {
      * @return the default render options
      */
     public static ConfigRenderOptions defaults() {
-        return new ConfigRenderOptions(true, true, true, true);
+        return new ConfigRenderOptions(true, true, true, true, new DefaultComparator());
     }
 
     /**
@@ -48,7 +53,7 @@ public final class ConfigRenderOptions {
      * @return the concise render options
      */
     public static ConfigRenderOptions concise() {
-        return new ConfigRenderOptions(false, false, false, true);
+        return new ConfigRenderOptions(false, false, false, true, new DefaultComparator());
     }
 
     /**
@@ -64,7 +69,7 @@ public final class ConfigRenderOptions {
         if (value == comments)
             return this;
         else
-            return new ConfigRenderOptions(originComments, value, formatted, json);
+            return new ConfigRenderOptions(originComments, value, formatted, json, new DefaultComparator());
     }
 
     /**
@@ -97,7 +102,7 @@ public final class ConfigRenderOptions {
         if (value == originComments)
             return this;
         else
-            return new ConfigRenderOptions(value, comments, formatted, json);
+            return new ConfigRenderOptions(value, comments, formatted, json, new DefaultComparator());
     }
 
     /**
@@ -122,7 +127,7 @@ public final class ConfigRenderOptions {
         if (value == formatted)
             return this;
         else
-            return new ConfigRenderOptions(originComments, comments, value, json);
+            return new ConfigRenderOptions(originComments, comments, value, json, new DefaultComparator());
     }
 
     /**
@@ -150,7 +155,7 @@ public final class ConfigRenderOptions {
         if (value == json)
             return this;
         else
-            return new ConfigRenderOptions(originComments, comments, formatted, value);
+            return new ConfigRenderOptions(originComments, comments, formatted, value, new DefaultComparator());
     }
 
     /**
@@ -163,6 +168,31 @@ public final class ConfigRenderOptions {
         return json;
     }
 
+    /**
+     * Returns options with a custom comparator to sort the keys in the
+     * rendered output.
+     *
+     * @param value
+     *            the comparator used to sort the keys in the output
+     * @return options with requested setting for the comparator
+     */
+    public ConfigRenderOptions setComparator(Comparator<String> value) {
+        if (value == comparator)
+            return this;
+        else
+            return new ConfigRenderOptions(originComments, comments, formatted, json, value);
+    }
+
+    /**
+     * Returns whether the options enable a custom comparator to sort
+     * the keys in the rendered output.
+     *
+     * @return the comparator set
+     */
+    public Comparator<String> getComparator() {
+        return comparator;
+    }
+
     @Override
     public String toString() {
         StringBuilder sb = new StringBuilder("ConfigRenderOptions(");
@@ -174,9 +204,53 @@ public final class ConfigRenderOptions {
             sb.append("formatted,");
         if (json)
             sb.append("json,");
+        if (comparator != null)
+            sb.append(comparator.getClass().getSimpleName());
         if (sb.charAt(sb.length() - 1) == ',')
             sb.setLength(sb.length() - 1);
         sb.append(")");
         return sb.toString();
     }
+
+    // this is only Serializable to chill out a findbugs warning
+    static final private class DefaultComparator implements java.util.Comparator<String>, Serializable {
+        private static final long serialVersionUID = 1L;
+
+        private static boolean isAllDigits(String s) {
+            int length = s.length();
+
+            // empty string doesn't count as a number
+            if (length == 0)
+                return false;
+
+            for (int i = 0; i < length; ++i) {
+                char c = s.charAt(i);
+
+                if (Character.isDigit(c))
+                    continue;
+                else
+                    return false;
+            }
+            return true;
+        }
+
+        // This is supposed to sort numbers before strings,
+        // and sort the numbers numerically. The point is
+        // to make objects which are really list-like
+        // (numeric indices) appear in order.
+        @Override
+        public int compare(String a, String b) {
+            boolean aDigits = isAllDigits(a);
+            boolean bDigits = isAllDigits(b);
+            if (aDigits && bDigits) {
+                return Integer.compare(Integer.parseInt(a), Integer.parseInt(b));
+            } else if (aDigits) {
+                return -1;
+            } else if (bDigits) {
+                return 1;
+            } else {
+                return a.compareTo(b);
+            }
+        }
+    }
 }

config/src/main/java/com/typesafe/config/impl/SimpleConfigObject.java

@@ -418,48 +418,6 @@ final class SimpleConfigObject extends AbstractConfigObject implements Serializa
         });
     }
 
-    // this is only Serializable to chill out a findbugs warning
-    static final private class RenderComparator implements java.util.Comparator<String>, Serializable {
-        private static final long serialVersionUID = 1L;
-
-        private static boolean isAllDigits(String s) {
-            int length = s.length();
-
-            // empty string doesn't count as a number
-            if (length == 0)
-                return false;
-
-            for (int i = 0; i < length; ++i) {
-                char c = s.charAt(i);
-
-                if (Character.isDigit(c))
-                    continue;
-                else
-                    return false;
-            }
-            return true;
-        }
-
-        // This is supposed to sort numbers before strings,
-        // and sort the numbers numerically. The point is
-        // to make objects which are really list-like
-        // (numeric indices) appear in order.
-        @Override
-        public int compare(String a, String b) {
-            boolean aDigits = isAllDigits(a);
-            boolean bDigits = isAllDigits(b);
-            if (aDigits && bDigits) {
-                return Integer.compare(Integer.parseInt(a), Integer.parseInt(b));
-            } else if (aDigits) {
-                return -1;
-            } else if (bDigits) {
-                return 1;
-            } else {
-                return a.compareTo(b);
-            }
-        }
-    }
-
     @Override
     protected void render(StringBuilder sb, int indent, boolean atRoot, ConfigRenderOptions options) {
         if (isEmpty()) {
@@ -480,7 +438,7 @@ final class SimpleConfigObject extends AbstractConfigObject implements Serializa
 
             int separatorCount = 0;
             String[] keys = keySet().toArray(new String[size()]);
-            Arrays.sort(keys, new RenderComparator());
+            Arrays.sort(keys, options.getComparator());
             for (String k : keys) {
                 AbstractConfigValue v;
                 v = value.get(k);