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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.databinding.tool.util;
     18 
     19 import android.databinding.tool.reflection.Callable;
     20 
     21 /**
     22  * Central place to convert method/field names to BR observable fields
     23  */
     24 public class BrNameUtil {
     25     private static String stripPrefixFromField(String name) {
     26         if (name.length() >= 2) {
     27             char firstChar = name.charAt(0);
     28             char secondChar = name.charAt(1);
     29             if (name.length() > 2 && firstChar == 'm' && secondChar == '_') {
     30                 char thirdChar = name.charAt(2);
     31                 if (Character.isJavaIdentifierStart(thirdChar)) {
     32                     return "" + Character.toLowerCase(thirdChar) +
     33                             name.subSequence(3, name.length());
     34                 }
     35             } else if ((firstChar == 'm' && Character.isUpperCase(secondChar)) ||
     36                     (firstChar == '_' && Character.isJavaIdentifierStart(secondChar))) {
     37                 return "" + Character.toLowerCase(secondChar) + name.subSequence(2, name.length());
     38             }
     39         }
     40         return name;
     41     }
     42 
     43     public static String brKey(Callable callable) {
     44         if (callable.type == Callable.Type.FIELD) {
     45             return stripPrefixFromField(callable.name);
     46         }
     47         CharSequence propertyName;
     48         final String name = callable.name;
     49         if (isGetter(callable) || isSetter(callable)) {
     50             propertyName = name.subSequence(3, name.length());
     51         } else if (isBooleanGetter(callable)) {
     52             propertyName = name.subSequence(2, name.length());
     53         } else {
     54             L.e("@Bindable associated with method must follow JavaBeans convention %s", callable);
     55             return null;
     56         }
     57         char firstChar = propertyName.charAt(0);
     58         return "" + Character.toLowerCase(firstChar) +
     59                 propertyName.subSequence(1, propertyName.length());
     60     }
     61 
     62     private static boolean isGetter(Callable callable) {
     63         return prefixes(callable.name, "get") &&
     64                 Character.isJavaIdentifierStart(callable.name.charAt(3)) &&
     65                 callable.getParameterCount() == 0 &&
     66                 !callable.resolvedType.isVoid();
     67     }
     68 
     69     private static boolean isSetter(Callable callable) {
     70         return prefixes(callable.name, "set") &&
     71                 Character.isJavaIdentifierStart(callable.name.charAt(3)) &&
     72                 callable.getParameterCount() == 1 &&
     73                 callable.resolvedType.isVoid();
     74     }
     75 
     76     private static boolean isBooleanGetter(Callable callable) {
     77         return prefixes(callable.name, "is") &&
     78                 Character.isJavaIdentifierStart(callable.name.charAt(2)) &&
     79                 callable.getParameterCount() == 0 &&
     80                 callable.resolvedType.isBoolean();
     81     }
     82 
     83     private static boolean prefixes(CharSequence sequence, String prefix) {
     84         boolean prefixes = false;
     85         if (sequence.length() > prefix.length()) {
     86             int count = prefix.length();
     87             prefixes = true;
     88             for (int i = 0; i < count; i++) {
     89                 if (sequence.charAt(i) != prefix.charAt(i)) {
     90                     prefixes = false;
     91                     break;
     92                 }
     93             }
     94         }
     95         return prefixes;
     96     }
     97 }
     98