1 /*
2  * Copyright (C) 2016 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 package android.databinding.tool.expr;
17 
18 import android.databinding.tool.CallbackWrapper;
19 import android.databinding.tool.processing.ErrorMessages;
20 import android.databinding.tool.reflection.ModelAnalyzer;
21 import android.databinding.tool.reflection.ModelClass;
22 import android.databinding.tool.util.Preconditions;
23 import android.databinding.tool.writer.KCode;
24 
25 import java.util.Collections;
26 import java.util.List;
27 
28 /**
29  * This expressions that are used to reference arguments in callbacks.
30  * <p
31  * While the callback is being parsed, they get whatever the variable user defined in the lambda.
32  * When the code is being generated, they get simple enumarated names so that multiple callbacks
33  * can be handled in the same method.
34  */
35 public class CallbackArgExpr extends IdentifierExpr {
36 
37     private int mArgIndex;
38 
39     private String mName;
40 
41     private ModelClass mClassFromCallback;
42 
CallbackArgExpr(int argIndex, String name)43     public CallbackArgExpr(int argIndex, String name) {
44         super(name);
45         mArgIndex = argIndex;
46         mName = name;
47     }
48 
49     @Override
isDynamic()50     public boolean isDynamic() {
51         return false;
52     }
53 
setClassFromCallback(ModelClass modelClass)54     public void setClassFromCallback(ModelClass modelClass) {
55         mClassFromCallback = modelClass;
56     }
57 
58     @Override
resolveType(ModelAnalyzer modelAnalyzer)59     protected ModelClass resolveType(ModelAnalyzer modelAnalyzer) {
60         Preconditions
61                 .checkNotNull(mClassFromCallback, ErrorMessages.UNDEFINED_CALLBACK_ARGUMENT, mName);
62         return mClassFromCallback;
63     }
64 
65     @Override
constructDependencies()66     protected List<Dependency> constructDependencies() {
67         return Collections.emptyList();
68     }
69 
70     @Override
generateCode()71     protected KCode generateCode() {
72         return new KCode(CallbackWrapper.ARG_PREFIX + mArgIndex);
73     }
74 
75     @Override
computeUniqueKey()76     protected String computeUniqueKey() {
77         return CallbackWrapper.ARG_PREFIX + mArgIndex;
78     }
79 
80     @Override
getInvertibleError()81     public String getInvertibleError() {
82         return "Callback arguments cannot be inverted";
83     }
84 
getName()85     public String getName() {
86         return mName;
87     }
88 
89     @Override
cloneToModel(ExprModel model)90     public Expr cloneToModel(ExprModel model) {
91         return new CallbackArgExpr(mArgIndex, mName);
92     }
93 }
94