Implement single quotes in MessageFormat

classpath/java/text/MessageFormat.java

@@ -12,6 +12,24 @@ package java.text;
 
 import java.util.Locale;
 
+/**
+ * A minimalist Java message formatter.
+ * The string is a sequence of letters, copied verbatim unless the letter
+ * is "{" or "'".  If the letter is a "{", this begins a parameter, which
+ * is a base-10 number.  {0} will be replaced by the first argument to
+ * format, {1} is the second argument, and so on.
+ * If the letter is a single tick ("'"), then all characters
+ * until the mathcing tick are outputted verbatim(this is useful for escaping
+ * the { character).
+ * <h3>Examples</h3>
+ * <table>
+ * <tr><th>format</th><th>Args</th><th>Result</th></tr>
+ * <tr><td>There are {0} grapes</td><td>six</td><td>There are six grapes</td></tr>
+ * <tr><td>{2} + {1} = {0}</td><td>5 2 3</td><td>3 + 2 = 5</td></tr>
+ * <tr><td>{0} and {0} and {0}</td><td>again</td><td>again and again and again</td></tr>
+ * <tr><td>Joe''s age is {0}, not '{0}'</td><td>30</td><td>Joe's age is 30, not {0}</td></tr>
+ * </table>
+ */
 public class MessageFormat extends Format {
   private String pattern;
   private final Locale locale;
@@ -25,31 +43,61 @@ public class MessageFormat extends Format {
     this(pattern, Locale.getDefault());
   }
 
-  public StringBuffer format(Object[] args, StringBuffer target,
-                             FieldPosition p)
-  {
-    // todo: handle other format substitutions and escapes, and make
-    // this more efficient:
-    String result = pattern;
-    int length = args.length;
-    for (int i = 0; i < length; i++) {
-      result = result.replace("{" + i + "}", String.valueOf(args[i]));
+  public StringBuffer format(Object args[], StringBuffer target, FieldPosition pos) {
+    int i=0;
+    int len=pattern.length();
+
+    while (i < len) {
+      char ch = pattern.charAt(i);
+      if (ch == '{') {
+        // Param should be a number
+        int num=0;
+        while (i < (len-1)) {
+          i++;
+          ch = pattern.charAt(i);
+          if ((ch >= '0') && (ch <= '9')) {
+            num = num * 10 + (ch - '0');
+          } else if (ch == '}') {
+            target.append((args[num] == null) ? "null" : args[num].toString());
+            break;
+          } else {
+            throw new IllegalArgumentException("Character within {} isn't digit: " + ch);
+          }
+        }
+      } else if (ch == '\'') {
+        // Char is a literal string
+        i++;
+        ch = pattern.charAt(i);
+        if (ch == '\'') {
+          target.append('\'');
+        } else {
+          while (ch != '\'') {
+            target.append(ch);
+            i++;
+            ch = pattern.charAt(i);
+          }
+        }
+      } else {
+        target.append(ch);
+      }
+      i++;
     }
-    return target.append(result);
+    return target;
   }
 
-  public StringBuffer format(Object args, StringBuffer target, FieldPosition p)
-  {
+  public static String format(String message, Object... args) {
+    return new MessageFormat(message).format(args, new StringBuffer(), new FieldPosition(0)).toString();
+  }
+
+  public StringBuffer format(Object args, StringBuffer target, FieldPosition p) {
     return format((Object[]) args, target, p);
   }
 
-  public static String format(String pattern, Object ... args) {
-    return new MessageFormat
-      (pattern).format(args, new StringBuffer(), new FieldPosition(0))
-      .toString();
-  }
-
   public void applyPattern(String pattern) {
     this.pattern = pattern;
   }
+
+  public String toPattern() {
+    return pattern;
+  }
 }