BracketExpr.java revision e0d5ed7613cb72192430cd2ed8e4159618ca308e 
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        return join(getTarget().computeUniqueKey(), "$", getArg().computeUniqueKey(), "$");
69    }
70
71    public Expr getTarget() {
72        return getChildren().get(0);
73    }
74
75    public Expr getArg() {
76        return getChildren().get(1);
77    }
78
79    public BracketAccessor getAccessor() {
80        return mAccessor;
81    }
82
83    public boolean argCastsInteger() {
84        return Object.class.equals(getArg().getResolvedType());
85    }
86
87    @Override
88    protected KCode generateCode() {
89        KCode code = new KCode()
90                .app("", getTarget().toCode());
91        switch (getAccessor()) {
92            case ARRAY:
93                return code.app("[", getArg().toCode()).app("]");
94            case LIST:
95                code.app(".get(");
96                if (argCastsInteger()) {
97                    code.app("(Integer)");
98                }
99                return code.app("", getArg().toCode()).app(")");
100            case MAP:
101                return code.app(".get(", getArg().toCode()).app(")");
102        }
103        throw new IllegalStateException("Invalid BracketAccessor type");
104    }
105}
106