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      1 /*
      2  * Copyright (C) 2016 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.processing.Scope;
     20 import android.databinding.tool.reflection.ModelAnalyzer;
     21 import android.databinding.tool.reflection.ModelClass;
     22 import android.databinding.tool.reflection.ModelMethod;
     23 import android.databinding.tool.solver.ExecutionPath;
     24 
     25 import java.util.ArrayList;
     26 import java.util.List;
     27 
     28 public abstract class MethodBaseExpr extends Expr {
     29     String mName;
     30 
     31     MethodBaseExpr(Expr parent, String name) {
     32         super(parent);
     33         mName = name;
     34     }
     35 
     36     public Expr getTarget() {
     37         return getChildren().get(0);
     38     }
     39 
     40     @Override
     41     public List<ExecutionPath> toExecutionPath(List<ExecutionPath> paths) {
     42         final List<ExecutionPath> targetPaths = getTarget().toExecutionPath(paths);
     43         // after this, we need a null check.
     44         List<ExecutionPath> result = new ArrayList<ExecutionPath>();
     45         if (getTarget() instanceof StaticIdentifierExpr) {
     46             result.addAll(toExecutionPathInOrder(paths, getTarget()));
     47         } else {
     48             for (ExecutionPath path : targetPaths) {
     49                 final ComparisonExpr cmp = getModel()
     50                         .comparison("!=", getTarget(), getModel().symbol("null", Object.class));
     51                 path.addPath(cmp);
     52                 final ExecutionPath subPath = path.addBranch(cmp, true);
     53                 if (subPath != null) {
     54                     subPath.addPath(this);
     55                     result.add(subPath);
     56                 }
     57             }
     58         }
     59         return result;
     60     }
     61 
     62     protected Expr resolveListenersAsMethodReference(ModelClass listener, Expr parent) {
     63         final Expr target = getTarget();
     64         final ModelClass childType = target.getResolvedType();
     65         if (listener == null) {
     66             throw new IllegalStateException(
     67                     String.format("Could not resolve %s as a listener.", this));
     68         }
     69 
     70         List<ModelMethod> abstractMethods = listener.getAbstractMethods();
     71         int numberOfAbstractMethods = abstractMethods == null ? 0 : abstractMethods.size();
     72         if (numberOfAbstractMethods != 1) {
     73             throw new IllegalStateException(String.format(
     74                     "Could not find accessor %s.%s and %s has %d abstract methods, so is" +
     75                             " not resolved as a listener",
     76                     childType.getCanonicalName(), mName,
     77                     listener.getCanonicalName(), numberOfAbstractMethods));
     78         }
     79 
     80         // Look for a signature matching the abstract method
     81         final ModelMethod listenerMethod = abstractMethods.get(0);
     82         final ModelClass[] listenerParameters = listenerMethod.getParameterTypes();
     83         boolean isStatic = getTarget() instanceof StaticIdentifierExpr;
     84         List<ModelMethod> methods = childType.findMethods(mName, isStatic);
     85         for (ModelMethod method : methods) {
     86             if (acceptsParameters(method, listenerParameters) &&
     87                     method.getReturnType(null).equals(listenerMethod.getReturnType(null))) {
     88                 target.getParents().remove(this);
     89                 resetResolvedType();
     90                 // replace this with ListenerExpr in parent
     91                 Expr listenerExpr = getModel().listenerExpr(getTarget(), mName, listener,
     92                         listenerMethod);
     93                 if (parent != null) {
     94                     int index;
     95                     while ((index = parent.getChildren().indexOf(this)) != -1) {
     96                         parent.getChildren().set(index, listenerExpr);
     97                     }
     98                 }
     99                 if (getModel().mBindingExpressions.contains(this)) {
    100                     getModel().bindingExpr(listenerExpr);
    101                 }
    102                 getParents().remove(parent);
    103                 if (getParents().isEmpty()) {
    104                     getModel().removeExpr(this);
    105                 }
    106                 return listenerExpr;
    107             }
    108         }
    109 
    110         throw new IllegalStateException(String.format(
    111                 "Listener class %s with method %s did not match signature of any method %s",
    112                 listener.getCanonicalName(), listenerMethod.getName(), this));
    113     }
    114 
    115     private boolean acceptsParameters(ModelMethod method, ModelClass[] listenerParameters) {
    116         ModelClass[] parameters = method.getParameterTypes();
    117         if (parameters.length != listenerParameters.length) {
    118             return false;
    119         }
    120         for (int i = 0; i < parameters.length; i++) {
    121             if (!parameters[i].isAssignableFrom(listenerParameters[i])) {
    122                 return false;
    123             }
    124         }
    125         return true;
    126     }
    127 
    128     @Override
    129     protected List<Dependency> constructDependencies() {
    130         final List<Dependency> dependencies = constructDynamicChildrenDependencies();
    131         for (Dependency dependency : dependencies) {
    132             if (dependency.getOther() == getTarget()) {
    133                 dependency.setMandatory(true);
    134             }
    135         }
    136         return dependencies;
    137     }
    138 
    139     public String getName() {
    140         return mName;
    141     }
    142 
    143     @Override
    144     public void updateExpr(ModelAnalyzer modelAnalyzer) {
    145         try {
    146             Scope.enter(this);
    147             resolveType(modelAnalyzer);
    148             super.updateExpr(modelAnalyzer);
    149         } finally {
    150             Scope.exit();
    151         }
    152     }
    153 }
    154