Merge pull request #140 from ralfs-gutmanis/master

Add ability to pass CharSequence instead of forcing String for contex…

src/main/gwt/com/samskivert/super/java/io/Writer.java

@@ -9,4 +9,6 @@ package java.io;
 public abstract class Writer
 {
     public abstract void write (String text) throws IOException;
+
+    public abstract Writer append (CharSequence text) throws IOException;
 }

src/main/java/com/samskivert/mustache/Mustache.java

@@ -207,10 +207,25 @@ public class Mustache {
           * then empty strings are considered falsey. If {@link #zeroIsFalse} is true, then zero
           * values are considered falsey. */
         public boolean isFalsey (Object value) {
-            return ((emptyStringIsFalse && "".equals(formatter.format(value))) ||
+            return ((emptyStringIsFalse && isEmptyCharSequence(formatter.format(value))) ||
                     (zeroIsFalse && (value instanceof Number) && ((Number)value).longValue() == 0));
         }
 
+        /**
+         * Replaces "".equals(value). E.g. only not null values with length 0
+         */
+        private boolean isEmptyCharSequence(Object value) {
+            if (value == null) {
+                return false;
+            }
+
+            if(value instanceof CharSequence) {
+                return ((CharSequence) value).length() == 0;
+            }
+
+            return false;
+        }
+
         /** Loads and compiles the template {@code name} using this compiler's configured template
           * loader. Note that this does no caching: the caller should cache the loaded template if
           * they expect to use it multiple times.
@@ -259,8 +274,8 @@ public class Mustache {
     /** Handles converting objects to strings when rendering templates. */
     public interface Formatter {
 
-        /** Converts {@code value} to a string for inclusion in a template. */
+        /** Converts {@code value} to a CharSequence for inclusion in a template. */
-        String format (Object value);
+        CharSequence format (Object value);
     }
 
     /** Handles lambdas. */
@@ -299,6 +314,11 @@ public class Mustache {
 
         /** Returns {@code raw} with the appropriate characters replaced with escape sequences. */
         String escape (String raw);
+
+        /** Returns {@code raw} with the appropriate characters replaced with escape sequences. **/
+        default CharSequence escape (CharSequence raw) {
+            return escape(raw.toString());
+        }
     }
 
     /** Handles loading partial templates. */

src/main/java/com/samskivert/mustache/Template.java

@@ -384,9 +384,9 @@ public class Template {
 
         abstract void visit (Mustache.Visitor visitor);
 
-        protected static void write (Writer out, String data) {
+        protected static void write (Writer out, CharSequence data) {
             try {
-                out.write(data);
+                out.append(data);
             } catch (IOException ioe) {
                 throw new MustacheException(ioe);
             }

src/test/java/com/samskivert/mustache/MustacheTest.java

@@ -17,9 +17,6 @@ import java.util.Optional;
 import java.util.TimeZone;
 
 import org.junit.Test;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
 
 /**
  * Mustache tests that can only be run on the JVM. Most tests should go in BaseMustacheTest so
@@ -54,6 +51,14 @@ public class MustacheTest extends SharedTests
         });
     }
 
+    @Test public void testCharSequenceVariable() {
+        Map<String, CharSequence> ctx = new HashMap<>();
+        StringBuffer stringBuffer = new StringBuffer();
+        stringBuffer.append("bar");
+        ctx.put("foo", stringBuffer);
+        test("bar", "{{foo}}", ctx);
+    }
+
     public interface HasDefault {
         default String getFoo () { return "bar"; }
     }