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      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 
     17 package android.databinding.tool.expr;
     18 
     19 import android.databinding.tool.reflection.ModelAnalyzer;
     20 import android.databinding.tool.reflection.ModelClass;
     21 import android.databinding.tool.reflection.ModelMethod;
     22 import android.databinding.tool.writer.KCode;
     23 import android.databinding.tool.writer.LayoutBinderWriterKt;
     24 
     25 import java.util.ArrayList;
     26 import java.util.List;
     27 
     28 /**
     29  * This wraps an expression, but makes it unique for a particular event listener type.
     30  * This is used to differentiate listener methods. For example:
     31  * <pre>
     32  *     public void onFoo(String str) {...}
     33  *     public void onFoo(int i) {...}
     34  * </pre>
     35  */
     36 public class ListenerExpr extends Expr {
     37     private final String mName;
     38     private final ModelClass mListenerType;
     39     private final ModelMethod mMethod;
     40 
     41     ListenerExpr(Expr expr, String name, ModelClass listenerType, ModelMethod method) {
     42         super(expr);
     43         mName = name;
     44         mListenerType = listenerType;
     45         mMethod = method;
     46     }
     47 
     48     @Override
     49     protected ModelClass resolveType(ModelAnalyzer modelAnalyzer) {
     50         return mListenerType;
     51     }
     52 
     53     public ModelMethod getMethod() {
     54         return mMethod;
     55     }
     56 
     57     public Expr getChild() {
     58         return getChildren().get(0);
     59     }
     60 
     61     public String getName() {
     62         return mName;
     63     }
     64 
     65     @Override
     66     public boolean isDynamic() {
     67         return getChild().isDynamic();
     68     }
     69 
     70     @Override
     71     protected List<Dependency> constructDependencies() {
     72         final List<Dependency> dependencies = new ArrayList<Dependency>();
     73         Dependency dependency = new Dependency(this, getChild());
     74         dependency.setMandatory(true);
     75         dependencies.add(dependency);
     76         return dependencies;
     77     }
     78 
     79     protected String computeUniqueKey() {
     80         return join(getResolvedType().getCanonicalName(), getChild().computeUniqueKey(), mName);
     81     }
     82 
     83     @Override
     84     public KCode generateCode(boolean expand) {
     85         KCode code = new KCode("(");
     86         final int minApi = Math.max(mListenerType.getMinApi(), mMethod.getMinApi());
     87         if (minApi > 1) {
     88             code.app("(getBuildSdkInt() < " + minApi + ") ? null : ");
     89         }
     90         final String fieldName = LayoutBinderWriterKt.getFieldName(this);
     91         final String listenerClassName = LayoutBinderWriterKt.getListenerClassName(this);
     92         final KCode value = getChild().toCode();
     93             code.app("((")
     94                     .app(fieldName)
     95                     .app(" == null) ? (")
     96                     .app(fieldName)
     97                     .app(" = new ")
     98                     .app(listenerClassName)
     99                     .app("()) : ")
    100                     .app(fieldName)
    101                     .app(")");
    102         if (getChild().isDynamic()) {
    103             code.app(".setValue(", value)
    104                     .app(")");
    105         }
    106         code.app(")");
    107         return code;
    108     }
    109 
    110     @Override
    111     public String getInvertibleError() {
    112         return "Listeners cannot be the target of a two-way binding";
    113     }
    114 }
    115