TernaryExpr.java revision 9784c9aaedeb863018f5fcaa0a598e8e2f8ed2f3 
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.ArrayList;
24import java.util.BitSet;
25import java.util.List;
26
27public class TernaryExpr extends Expr {
28    TernaryExpr(Expr pred, Expr ifTrue, Expr ifFalse) {
29        super(pred, ifTrue, ifFalse);
30    }
31
32    public Expr getPred() {
33        return getChildren().get(0);
34    }
35
36    public Expr getIfTrue() {
37        return getChildren().get(1);
38    }
39
40    public Expr getIfFalse() {
41        return getChildren().get(2);
42    }
43
44    @Override
45    protected String computeUniqueKey() {
46        return "?:" + super.computeUniqueKey();
47    }
48
49    @Override
50    protected ModelClass resolveType(ModelAnalyzer modelAnalyzer) {
51        final Expr ifTrue = getIfTrue();
52        final Expr ifFalse = getIfFalse();
53        if (isNullLiteral(ifTrue)) {
54            return ifFalse.getResolvedType();
55        } else if (isNullLiteral(ifFalse)) {
56            return ifTrue.getResolvedType();
57        }
58        return modelAnalyzer.findCommonParentOf(getIfTrue().getResolvedType(),
59                getIfFalse().getResolvedType());
60    }
61
62    private static boolean isNullLiteral(Expr expr) {
63        final ModelClass type = expr.getResolvedType();
64        return (type.isObject() && (expr instanceof SymbolExpr) &&
65                "null".equals(((SymbolExpr)expr).getText()));
66    }
67
68    @Override
69    protected List<Dependency> constructDependencies() {
70        List<Dependency> deps = new ArrayList<Dependency>();
71        Expr predExpr = getPred();
72        final Dependency pred = new Dependency(this, predExpr);
73        pred.setMandatory(true);
74        deps.add(pred);
75
76        Expr ifTrueExpr = getIfTrue();
77        if (ifTrueExpr.isDynamic()) {
78            deps.add(new Dependency(this, ifTrueExpr, predExpr, true));
79        }
80        Expr ifFalseExpr = getIfFalse();
81        if (ifFalseExpr.isDynamic()) {
82            deps.add(new Dependency(this, ifFalseExpr, predExpr, false));
83        }
84        return deps;
85    }
86
87    @Override
88    protected BitSet getPredicateInvalidFlags() {
89        return getPred().getInvalidFlags();
90    }
91
92    @Override
93    protected KCode generateCode() {
94        return new KCode()
95                .app("", getPred().toCode())
96                .app(" ? ", getIfTrue().toCode())
97                .app(" : ", getIfFalse().toCode());
98
99    }
100
101    @Override
102    public boolean isConditional() {
103        return true;
104    }
105}
106