BracketExpr.java revision d3f2b9229472c9dae9bf4ae8b3e2d653b5653b01 
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
17package android.databinding.tool.expr;
18
19import android.databinding.tool.reflection.ModelAnalyzer;
20import android.databinding.tool.reflection.ModelClass;
21import android.databinding.tool.writer.KCode;
22
23import java.util.List;
24
25public class BracketExpr extends Expr {
26
27    public static enum BracketAccessor {
28        ARRAY,
29        LIST,
30        MAP,
31    }
32
33    private BracketAccessor mAccessor;
34
35    BracketExpr(Expr target, Expr arg) {
36        super(target, arg);
37    }
38
39    @Override
40    protected ModelClass resolveType(ModelAnalyzer modelAnalyzer) {
41        ModelClass targetType = getTarget().getResolvedType();
42        if (targetType.isArray()) {
43            mAccessor = BracketAccessor.ARRAY;
44        } else if (targetType.isList()) {
45            mAccessor = BracketAccessor.LIST;
46        } else if (targetType.isMap()) {
47            mAccessor = BracketAccessor.MAP;
48        } else {
49            throw new IllegalArgumentException("Cannot determine variable type used in [] " +
50                    "expression. Cast the value to List, Map, " +
51                    "or array. Type detected: " + targetType.toJavaCode());
52        }
53        return targetType.getComponentType();
54    }
55
56    @Override
57    protected List<Dependency> constructDependencies() {
58        final List<Dependency> dependencies = constructDynamicChildrenDependencies();
59        for (Dependency dependency : dependencies) {
60            if (dependency.getOther() == getTarget()) {
61                dependency.setMandatory(true);
62            }
63        }
64        return dependencies;
65    }
66
67    protected String computeUniqueKey() {
68        final String targetKey = getTarget().computeUniqueKey();
69        return addTwoWay(join(targetKey, "$", getArg().computeUniqueKey(), "$"));
70    }
71
72    @Override
73    public String getInvertibleError() {
74        return null;
75    }
76
77    public Expr getTarget() {
78        return getChildren().get(0);
79    }
80
81    public Expr getArg() {
82        return getChildren().get(1);
83    }
84
85    public BracketAccessor getAccessor() {
86        return mAccessor;
87    }
88
89    public boolean argCastsInteger() {
90        return mAccessor != BracketAccessor.MAP && getArg().getResolvedType().isObject();
91    }
92
93    @Override
94    protected KCode generateCode(boolean expand) {
95        String cast = argCastsInteger() ? "(Integer) " : "";
96        switch (getAccessor()) {
97            case ARRAY: {
98                return new KCode().
99                        app("getFromArray(", getTarget().toCode()).
100                        app(", ").
101                        app(cast, getArg().toCode()).app(")");
102            }
103            case LIST: {
104                ModelClass listType = ModelAnalyzer.getInstance().findClass(java.util.List.class).
105                        erasure();
106                ModelClass targetType = getTarget().getResolvedType().erasure();
107                if (listType.isAssignableFrom(targetType)) {
108                    return new KCode().
109                            app("getFromList(", getTarget().toCode()).
110                            app(", ").
111                            app(cast, getArg().toCode()).
112                            app(")");
113                } else {
114                    return new KCode().
115                            app("", getTarget().toCode()).
116                            app(".get(").
117                            app(cast, getArg().toCode()).
118                            app(")");
119                }
120            }
121            case MAP:
122                return new KCode().
123                        app("", getTarget().toCode()).
124                        app(".get(", getArg().toCode()).
125                        app(")");
126        }
127        throw new IllegalStateException("Invalid BracketAccessor type");
128    }
129
130    @Override
131    public KCode toInverseCode(KCode value) {
132        String cast = argCastsInteger() ? "(Integer) " : "";
133        return new KCode().
134                app("setTo(", getTarget().toCode(true)).
135                app(", ").
136                app(cast, getArg().toCode(true)).
137                app(", ", value).app(");");
138    }
139}
140