MergedBinding.java revision e52882df6130221462bf07f5f2b52de5c4b0f8de 
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;
18
19import android.databinding.tool.expr.ArgListExpr;
20import android.databinding.tool.expr.Expr;
21import android.databinding.tool.expr.ExprModel;
22import android.databinding.tool.reflection.ModelClass;
23import android.databinding.tool.store.SetterStore;
24import android.databinding.tool.util.L;
25import android.databinding.tool.writer.WriterPackage;
26
27import java.lang.reflect.Array;
28import java.util.ArrayList;
29import java.util.Arrays;
30import java.util.List;
31
32/**
33 * Multiple binding expressions can be evaluated using a single adapter. In those cases,
34 * we replace the Binding with a MergedBinding.
35 */
36public class MergedBinding extends Binding {
37    private final SetterStore.MultiAttributeSetter mMultiAttributeSetter;
38    public MergedBinding(ExprModel model, SetterStore.MultiAttributeSetter multiAttributeSetter,
39            BindingTarget target, Iterable<Binding> bindings) {
40        super(target, createMergedName(bindings), createArgListExpr(model, bindings));
41        mMultiAttributeSetter = multiAttributeSetter;
42    }
43
44    private static Expr createArgListExpr(ExprModel model, final Iterable<Binding> bindings) {
45        List<Expr> args = new ArrayList<>();
46        for (Binding binding : bindings) {
47            args.add(binding.getExpr());
48        }
49        Expr expr = model.argListExpr(args);
50        expr.setBindingExpression(true);
51        return expr;
52    }
53
54    private static String createMergedName(Iterable<Binding> bindings) {
55        StringBuilder sb = new StringBuilder();
56        for (Binding binding : bindings) {
57            sb.append(binding.getName());
58        }
59        return sb.toString();
60    }
61
62    @Override
63    public void resolveListeners() {
64        ModelClass[] params = mMultiAttributeSetter.getParameterTypes();
65        List<Expr> expressions = getExpr().getChildren();
66        for (int i = 0; i < params.length; i++) {
67            expressions.get(i).resolveListeners(params[i]);
68        }
69    }
70
71    public Expr[] getComponentExpressions() {
72        ArgListExpr args = (ArgListExpr) getExpr();
73        return args.getChildren().toArray(new Expr[args.getChildren().size()]);
74    }
75
76    @Override
77    public String getBindingAdapterInstanceClass() {
78        return mMultiAttributeSetter.getBindingAdapterInstanceClass();
79    }
80
81    @Override
82    public void setBindingAdapterCall(String method) {
83        mMultiAttributeSetter.setBindingAdapterCall(method);
84    }
85
86    @Override
87    public boolean requiresOldValue() {
88        return mMultiAttributeSetter.requiresOldValue();
89    }
90
91    @Override
92    public int getMinApi() {
93        return 1;
94    }
95
96    @Override
97    public String toJavaCode(String targetViewName, String bindingComponent) {
98        final ArgListExpr args = (ArgListExpr) getExpr();
99        final List<String> newValues = new ArrayList<>();
100        for (Expr expr : args.getChildren()) {
101            newValues.add(expr.toCode().generate());
102        }
103        final List<String> oldValues;
104        if (requiresOldValue()) {
105            oldValues = new ArrayList<>();
106            for (Expr expr : args.getChildren()) {
107                oldValues.add("this." + WriterPackage.getOldValueName(expr));
108            }
109        } else {
110            oldValues = Arrays.asList(new String[args.getChildren().size()]);
111        }
112        final String[] expressions = concat(oldValues, newValues, String.class);
113        L.d("merged binding arg: %s", args.getUniqueKey());
114        return mMultiAttributeSetter.toJava(bindingComponent, targetViewName, expressions);
115    }
116
117    private static <T> T[] concat(List<T> l1, List<T> l2, Class<T> klass) {
118        List<T> result = new ArrayList<>();
119        result.addAll(l1);
120        result.addAll(l2);
121        return result.toArray((T[]) Array.newInstance(klass, result.size()));
122    }
123}
124