// Copyright 2020 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package com.google.api.generator.engine.escaper;

import com.google.common.escape.Escaper;
import com.google.common.escape.Escapers;

public class MetacharEscaper extends Escaper {
  // Handle escape characters (https://docs.oracle.com/javase/tutorial/java/data/characters.html)
  // for the comments here, else JavaFormmater cannot properly format the string comment.
  // `"` and `'` are overlooked because the comments will not be surrounded by `"` or `'`.
  private static final Escaper escaper =
      Escapers.builder()
          .addEscape('\t', "\\t")
          .addEscape('\b', "\\b")
          .addEscape('\r', "\\r")
          .addEscape('\f', "\\f")
          .addEscape('\n', "\\n")
          .addEscape('\\', "\\\\")
          .build();

  private MetacharEscaper() {}

  @Override
  public String escape(String sourceString) {
    return escaper.escape(sourceString);
  }

  public static String escaper(String source) {
    return new MetacharEscaper().escape(source);
  }
}

@@ -763,16 +763,91 @@
 caper %7B%0A
+  private static final MetacharEscaper SINGLETON = new MetacharEscaper();%0A%0A
   // Han
@@ -936,16 +936,16 @@
 s.html)%0A
-
   // for
@@ -1148,17 +1148,21 @@
 Escaper 
-e
+charE
 scaper =
@@ -1514,17 +1514,21 @@
  return 
-e
+charE
 scaper.e
@@ -1612,37 +1612,25 @@
  return 
-new MetacharEscaper()
+SINGLETON
 .escape(

use singleton in MetacharEscaper (#273)