Support multi-param adapters in code generation

Bug: 19800022

Change-Id: I40c4ac72f24f965db12fd1c7dec6591184160ae5

17 files changed, 774 insertions, 115 deletions

diff --git a/compiler/src/main/java/android/databinding/tool/Binding.java b/compiler/src/main/java/android/databinding/tool/Binding.java
index f2bc96fe..657cd7bc 100644
--- a/compiler/src/main/java/android/databinding/tool/Binding.java
+++ b/compiler/src/main/java/android/databinding/tool/Binding.java
@@ -21,6 +21,7 @@ import android.databinding.tool.reflection.ModelAnalyzer;
 import android.databinding.tool.reflection.ModelClass;
 import android.databinding.tool.store.SetterStore;
 import android.databinding.tool.store.SetterStore.SetterCall;
+import android.databinding.tool.writer.CodeGenUtil;
 
 public class Binding {
 
@@ -35,7 +36,7 @@ public class Binding {
         mExpr = expr;
     }
 
-    private SetterStore.SetterCall getSetterCall() {
+    private SetterStore.BindingSetterCall getSetterCall() {
         if (mSetterCall == null) {
             ModelClass viewType = mTarget.getResolvedType();
             if (viewType != null && viewType.extendsViewStub()) {
@@ -56,8 +57,9 @@ public class Binding {
         return mTarget;
     }
 
-    public String toJavaCode(String targetViewName, String expressionCode) {
-        return getSetterCall().toJava(targetViewName, expressionCode);
+    public String toJavaCode(String targetViewName) {
+        String argCode = CodeGenUtil.Companion.toCode(getExpr(), false).generate();
+        return getSetterCall().toJava(targetViewName, argCode);
     }
 
     /**
@@ -70,15 +72,6 @@ public class Binding {
         return getSetterCall().getMinApi();
     }
 
-//    private String resolveJavaCode(ModelAnalyzer modelAnalyzer) {
-//
-//    }
-////        return modelAnalyzer.findMethod(mTarget.getResolvedType(), mName,
-////                Arrays.asList(mExpr.getResolvedType()));
-//    //}
-//
-
-
     public String getName() {
         return mName;
     }
diff --git a/compiler/src/main/java/android/databinding/tool/BindingTarget.java b/compiler/src/main/java/android/databinding/tool/BindingTarget.java
index bc52a2a1..da2c5036 100644
--- a/compiler/src/main/java/android/databinding/tool/BindingTarget.java
+++ b/compiler/src/main/java/android/databinding/tool/BindingTarget.java
@@ -16,15 +16,24 @@
 
 package android.databinding.tool;
 
+import com.google.common.base.Function;
+import com.google.common.base.Preconditions;
+import com.google.common.base.Predicate;
+import com.google.common.collect.Iterables;
+
 import android.databinding.tool.expr.Expr;
 import android.databinding.tool.expr.ExprModel;
 import android.databinding.tool.reflection.ModelAnalyzer;
 import android.databinding.tool.reflection.ModelClass;
 import android.databinding.tool.store.ResourceBundle;
 import android.databinding.tool.store.SetterStore;
+import android.databinding.tool.util.L;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 public class BindingTarget {
     List<Binding> mBindings = new ArrayList<Binding>();
@@ -99,4 +108,66 @@ public class BindingTarget {
     public void setModel(ExprModel model) {
         mModel = model;
     }
+
+    /**
+     * Called after BindingTarget is finalized.
+     * <p>
+     * We traverse all bindings and ask SetterStore to figure out if any can be combined.
+     * When N bindings are combined, they are demoted from being a binding expression and a new
+     * ArgList expression is added as the new binding expression that depends on others.
+     */
+    public void resolveMultiSetters() {
+        L.d("resolving multi setters for %s", getId());
+        final SetterStore setterStore = SetterStore.get(ModelAnalyzer.getInstance());
+        final String[] attributes = new String[mBindings.size()];
+        final ModelClass[] types = new ModelClass[mBindings.size()];
+        for (int i = 0; i < mBindings.size(); i ++) {
+            Binding binding = mBindings.get(i);
+            attributes[i] = binding.getName();
+            types[i] = binding.getExpr().getResolvedType();
+        }
+        final List<SetterStore.MultiAttributeSetter> multiAttributeSetterCalls = setterStore
+                .getMultiAttributeSetterCalls(attributes, getResolvedType(), types);
+        if (multiAttributeSetterCalls.isEmpty()) {
+            return;
+        }
+        final Map<String, Binding> lookup = new HashMap<String, Binding>();
+        for (Binding binding : mBindings) {
+            String name = binding.getName();
+            if (name.startsWith("android:")) {
+                lookup.put(name, binding);
+            } else {
+                int ind = name.indexOf(":");
+                if (ind == -1) {
+                    lookup.put(name, binding);
+                } else {
+                    lookup.put(name.substring(ind + 1), binding);
+                }
+            }
+        }
+        List<MergedBinding> mergeBindings = new ArrayList<MergedBinding>();
+        for (final SetterStore.MultiAttributeSetter setter : multiAttributeSetterCalls) {
+            L.d("resolved %s", setter);
+            final Binding[] mergedBindings = Iterables.toArray(
+                    Iterables.transform(Arrays.asList(setter.attributes),
+                            new Function<String, Binding>() {
+                                @Override
+                                public Binding apply(final String attribute) {
+                                    L.d("looking for binding for attribute %s", attribute);
+                                    return lookup.get(attribute);
+                                }
+                            }), Binding.class) ;
+            Preconditions.checkArgument(mergedBindings.length == setter.attributes.length);
+            for (Binding binding : mergedBindings) {
+                binding.getExpr().setBindingExpression(false);
+                mBindings.remove(binding);
+            }
+            MergedBinding mergedBinding = new MergedBinding(getModel(), setter, this,
+                    Arrays.asList(mergedBindings));
+            mergeBindings.add(mergedBinding);
+        }
+        for (MergedBinding binding : mergeBindings) {
+            mBindings.add(binding);
+        }
+    }
 }
diff --git a/compiler/src/main/java/android/databinding/tool/LayoutBinder.java b/compiler/src/main/java/android/databinding/tool/LayoutBinder.java
index d8669271..669ed96e 100644
--- a/compiler/src/main/java/android/databinding/tool/LayoutBinder.java
+++ b/compiler/src/main/java/android/databinding/tool/LayoutBinder.java
@@ -22,8 +22,10 @@ import android.databinding.tool.expr.Dependency;
 import android.databinding.tool.expr.Expr;
 import android.databinding.tool.expr.ExprModel;
 import android.databinding.tool.expr.IdentifierExpr;
+import android.databinding.tool.reflection.ModelAnalyzer;
 import android.databinding.tool.store.ResourceBundle;
 import android.databinding.tool.store.ResourceBundle.BindingTargetBundle;
+import android.databinding.tool.store.SetterStore;
 import android.databinding.tool.util.ParserHelper;
 import android.databinding.tool.writer.LayoutBinderWriter;
 import android.databinding.tool.writer.WriterPackage;
@@ -81,6 +83,7 @@ public class LayoutBinder {
                     .getBindingBundleList()) {
                 bindingTarget.addBinding(bindingBundle.getName(), parse(bindingBundle.getExpr()));
             }
+            bindingTarget.resolveMultiSetters();
         }
         mSortedBindingTargets = new ArrayList<BindingTarget>(mBindingTargets);
         Collections.sort(mSortedBindingTargets, COMPARE_FIELD_NAME);
diff --git a/compiler/src/main/java/android/databinding/tool/MergedBinding.java b/compiler/src/main/java/android/databinding/tool/MergedBinding.java
new file mode 100644
index 00000000..174f89da
--- /dev/null
+++ b/compiler/src/main/java/android/databinding/tool/MergedBinding.java
@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.databinding.tool;
+
+import com.google.common.base.Function;
+import com.google.common.collect.Iterables;
+
+import org.apache.commons.lang3.StringUtils;
+
+import android.databinding.tool.expr.ArgListExpr;
+import android.databinding.tool.expr.Expr;
+import android.databinding.tool.expr.ExprModel;
+import android.databinding.tool.reflection.ModelAnalyzer;
+import android.databinding.tool.store.SetterStore;
+import android.databinding.tool.util.L;
+import android.databinding.tool.writer.CodeGenUtil;
+
+import java.util.List;
+
+/**
+ * Multiple binding expressions can be evaluated using a single adapter. In those cases,
+ * we replace the Binding with a MergedBinding.
+ */
+public class MergedBinding extends Binding {
+    private final SetterStore.MultiAttributeSetter mMultiAttributeSetter;
+    public MergedBinding(ExprModel model, SetterStore.MultiAttributeSetter multiAttributeSetter,
+            BindingTarget target, Iterable<Binding> bindings) {
+        super(target, createMergedName(bindings), createArgListExpr(model, bindings));
+        mMultiAttributeSetter = multiAttributeSetter;
+    }
+
+    private static Expr createArgListExpr(ExprModel model, final Iterable<Binding> bindings) {
+        Expr expr = model.argListExpr(Iterables.transform(bindings, new Function<Binding, Expr>() {
+            @Override
+            public Expr apply(Binding input) {
+                return input.getExpr();
+            }
+        }));
+        expr.setBindingExpression(true);
+        return expr;
+    }
+
+    private static String createMergedName(Iterable<Binding> bindings) {
+        return Iterables.toString(Iterables.transform(bindings, new Function<Binding, String>() {
+            @Override
+            public String apply(Binding input) {
+                return input.getName();
+            }
+        }));
+    }
+
+    @Override
+    public int getMinApi() {
+        return 1;
+    }
+
+    @Override
+    public String toJavaCode(String targetViewName) {
+        ArgListExpr args = (ArgListExpr) getExpr();
+        final String[] expressions = Iterables
+                .toArray(Iterables.transform(args.getChildren(), new Function<Expr, String>() {
+                    @Override
+                    public String apply(Expr input) {
+                        return CodeGenUtil.Companion.toCode(input, false).generate();
+                    }
+                }), String.class);
+        L.d("merged binding arg: %s", args.getUniqueKey());
+        return mMultiAttributeSetter.toJava(targetViewName, expressions);
+    }
+}
diff --git a/compiler/src/main/java/android/databinding/tool/expr/ArgListExpr.java b/compiler/src/main/java/android/databinding/tool/expr/ArgListExpr.java
new file mode 100644
index 00000000..91ae6495
--- /dev/null
+++ b/compiler/src/main/java/android/databinding/tool/expr/ArgListExpr.java
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.databinding.tool.expr;
+
+import android.databinding.tool.reflection.ModelAnalyzer;
+import android.databinding.tool.reflection.ModelClass;
+
+import java.util.List;
+
+/**
+ * This is a special expression that is created when we have an adapter that has multiple
+ * parameters.
+ * <p>
+ * When it is detected, we create a new binding with this argument list expression and merge N
+ * bindings into a new one so that rest of the code generation logic works as expected.
+ */
+public class ArgListExpr extends Expr {
+    private int mId;
+    public ArgListExpr(int id, Iterable<Expr> children) {
+        super(children);
+        mId = id;
+    }
+
+    @Override
+    protected String computeUniqueKey() {
+        return "ArgList[" + mId + "]" + super.computeUniqueKey();
+    }
+
+    @Override
+    protected ModelClass resolveType(ModelAnalyzer modelAnalyzer) {
+        return modelAnalyzer.findClass(Void.class);
+    }
+
+    @Override
+    protected List<Dependency> constructDependencies() {
+        return super.constructDynamicChildrenDependencies();
+    }
+
+    @Override
+    public boolean canBeEvaluatedToAVariable() {
+        return false;
+    }
+}
diff --git a/compiler/src/main/java/android/databinding/tool/expr/Expr.java b/compiler/src/main/java/android/databinding/tool/expr/Expr.java
index 84f16404..7e3849c0 100644
--- a/compiler/src/main/java/android/databinding/tool/expr/Expr.java
+++ b/compiler/src/main/java/android/databinding/tool/expr/Expr.java
@@ -25,6 +25,7 @@ import com.google.common.collect.Lists;
 
 import android.databinding.tool.reflection.ModelAnalyzer;
 import android.databinding.tool.reflection.ModelClass;
+import android.databinding.tool.writer.KCode;
 
 import java.util.ArrayList;
 import java.util.BitSet;
@@ -144,6 +145,10 @@ abstract public class Expr {
         return mIsBindingExpression;
     }
 
+    public boolean canBeEvaluatedToAVariable() {
+        return true; // anything except arg expr can be evaluated to a variable
+    }
+
     public boolean isObservable() {
         return getResolvedType().isObservable();
     }
@@ -199,7 +204,7 @@ abstract public class Expr {
         for (Dependency dependency : getDependants()) {
             final boolean isElevated = unreadElevatedCheck.apply(dependency);
             if (dependency.isConditional()) {
-                continue; // TODO
+                continue; // will be resolved later when conditional is elevated
             }
             if (isElevated) {
                 // if i already have all flags that will require my dependant's predicate to
diff --git a/compiler/src/main/java/android/databinding/tool/expr/ExprModel.java b/compiler/src/main/java/android/databinding/tool/expr/ExprModel.java
index 37455452..0847e287 100644
--- a/compiler/src/main/java/android/databinding/tool/expr/ExprModel.java
+++ b/compiler/src/main/java/android/databinding/tool/expr/ExprModel.java
@@ -42,6 +42,9 @@ public class ExprModel {
 
     private int mRequirementIdCount = 0;
 
+    // each arg list receives a unique id even if it is the same arguments and method.
+    private int mArgListIdCounter = 0;
+
     private static final String TRUE_KEY_SUFFIX = "== true";
     private static final String FALSE_KEY_SUFFIX = "== false";
 
@@ -67,6 +70,8 @@ public class ExprModel {
 
     private List<Expr> mObservables;
 
+    private boolean mSealed = false;
+
     private Map<String, String> mImports = new HashMap<String, String>();
 
     /**
@@ -77,6 +82,7 @@ public class ExprModel {
      * @return The expression itself or another one if the same thing was parsed before
      */
     public <T extends Expr> T register(T expr) {
+        Preconditions.checkState(!mSealed, "Cannot add expressions to a model after it is sealed");
         T existing = (T) mExprMap.get(expr.getUniqueKey());
         if (existing != null) {
             Preconditions.checkState(expr.getParents().isEmpty(),
@@ -371,7 +377,7 @@ public class ExprModel {
             expr.getResolvedType();
         }
 
-
+        mSealed = true;
     }
 
     public int getFlagBucketCount() {
@@ -529,4 +535,8 @@ public class ExprModel {
     public BitSet getInvalidateAnyBitSet() {
         return mInvalidateAnyFlags;
     }
+
+    public Expr argListExpr(Iterable<Expr> expressions) {
+        return register(new ArgListExpr(mArgListIdCounter ++, expressions));
+    }
 }
diff --git a/compiler/src/main/java/android/databinding/tool/expr/FieldAccessExpr.java b/compiler/src/main/java/android/databinding/tool/expr/FieldAccessExpr.java
index ad0d948a..24e62323 100644
--- a/compiler/src/main/java/android/databinding/tool/expr/FieldAccessExpr.java
+++ b/compiler/src/main/java/android/databinding/tool/expr/FieldAccessExpr.java
@@ -105,7 +105,7 @@ public class FieldAccessExpr extends Expr {
             child.resolveType(modelAnalyzer);
             boolean isStatic = child instanceof StaticIdentifierExpr;
             ModelClass resolvedType = child.getResolvedType();
-            L.d("resolving %s. Resolved type: %s", this, resolvedType);
+            L.d("resolving %s. Resolved class type: %s", this, resolvedType);
 
             mGetter = resolvedType.findGetterOrField(mName, isStatic);
             if (mGetter.resolvedType.isObservableField()) {
diff --git a/compiler/src/main/java/android/databinding/tool/store/SetterStore.java b/compiler/src/main/java/android/databinding/tool/store/SetterStore.java
index 0066ca15..2b2442e5 100644
--- a/compiler/src/main/java/android/databinding/tool/store/SetterStore.java
+++ b/compiler/src/main/java/android/databinding/tool/store/SetterStore.java
@@ -857,7 +857,13 @@ public class SetterStore {
         }
     }
 
-    public static abstract class SetterCall {
+    public static interface BindingSetterCall {
+        String toJava(String viewExpression, String... valueExpressions);
+
+        int getMinApi();
+    }
+
+    public static abstract class SetterCall implements BindingSetterCall {
         private MethodDescription mConverter;
         protected String mCastString = "";
 
@@ -870,8 +876,10 @@ public class SetterStore {
 
         protected abstract String toJavaInternal(String viewExpression, String converted);
 
-        public final String toJava(String viewExpression, String valueExpression) {
-            return toJavaInternal(viewExpression, convertValue(valueExpression));
+        @Override
+        public final String toJava(String viewExpression, String... valueExpression) {
+            Preconditions.checkArgument(valueExpression.length == 1);
+            return toJavaInternal(viewExpression, convertValue(valueExpression[0]));
         }
 
         protected String convertValue(String valueExpression) {
@@ -886,7 +894,7 @@ public class SetterStore {
         }
     }
 
-    public static class MultiAttributeSetter {
+    public static class MultiAttributeSetter implements BindingSetterCall {
         public final String[] attributes;
         private final MethodDescription mAdapter;
         private final MethodDescription[] mConverters;
@@ -905,8 +913,11 @@ public class SetterStore {
             this.mKey = key;
         }
 
-        public String toJava(String viewExpression, String[] valueExpressions) {
-            Preconditions.checkArgument(valueExpressions.length == attributes.length);
+        @Override
+        public final String toJava(String viewExpression, String[] valueExpressions) {
+            Preconditions.checkArgument(valueExpressions.length == attributes.length,
+                    "MultiAttributeSetter needs %s items, received %s",
+                    Arrays.toString(attributes), Arrays.toString(valueExpressions));
             StringBuilder sb = new StringBuilder();
             sb.append(mAdapter.type)
                     .append('.')
@@ -935,5 +946,21 @@ public class SetterStore {
             sb.append(')');
             return sb.toString();
         }
+
+        @Override
+        public int getMinApi() {
+            return 1;
+        }
+
+        @Override
+        public String toString() {
+            return "MultiAttributeSetter{" +
+                    "attributes=" + Arrays.toString(attributes) +
+                    ", mAdapter=" + mAdapter +
+                    ", mConverters=" + Arrays.toString(mConverters) +
+                    ", mCasts=" + Arrays.toString(mCasts) +
+                    ", mKey=" + mKey +
+                    '}';
+        }
     }
 }
diff --git a/compiler/src/main/kotlin/android/databinding/tool/writer/CodeGenUtil.kt b/compiler/src/main/kotlin/android/databinding/tool/writer/CodeGenUtil.kt
new file mode 100644
index 00000000..4ddfe88a
--- /dev/null
+++ b/compiler/src/main/kotlin/android/databinding/tool/writer/CodeGenUtil.kt
@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.databinding.tool.writer
+
+import android.databinding.tool.expr.*
+import android.databinding.tool.reflection.Callable
+import android.databinding.tool.writer.KCode
+import android.databinding.tool.writer.kcode
+
+class CodeGenUtil {
+    companion object {
+        fun toCode(it : Expr, full : Boolean) : KCode {
+            if (it.isDynamic() && !full) {
+                return kcode(it.executePendingLocalName)
+            }
+            return when (it) {
+                is ComparisonExpr -> kcode("") {
+                    app("", it.getLeft().toCode())
+                    app(it.getOp())
+                    app("", it.getRight().toCode())
+                }
+                is InstanceOfExpr -> kcode("") {
+                    app("", it.getExpr().toCode())
+                    app(" instanceof ")
+                    app("", it.getType().toJavaCode())
+                }
+                is FieldAccessExpr -> kcode("") {
+                    app("", it.getChild().toCode())
+                    if (it.getGetter().type == Callable.Type.FIELD) {
+                        app(".", it.getGetter().name)
+                    } else {
+                        app(".", it.getGetter().name).app("()")
+                    }
+                }
+                is GroupExpr -> kcode("(").app("", it.getWrapped().toCode()).app(")")
+                is StaticIdentifierExpr -> kcode(it.getResolvedType().toJavaCode())
+                is IdentifierExpr -> kcode(it.executePendingLocalName)
+                is MathExpr -> kcode("") {
+                    app("", it.getLeft().toCode())
+                    app(it.getOp())
+                    app("", it.getRight().toCode())
+                }
+                is UnaryExpr -> kcode("") {
+                    app(it.getOp(), it.getExpr().toCode())
+                }
+                is BitShiftExpr -> kcode("") {
+                    app("", it.getLeft().toCode())
+                    app(it.getOp())
+                    app("", it.getRight().toCode())
+                }
+                is MethodCallExpr -> kcode("") {
+                    app("", it.getTarget().toCode())
+                    app(".", it.getGetter().name)
+                    app("(")
+                    var first = true
+                    it.getArgs().forEach {
+                        apps(if (first) "" else ",", it.toCode())
+                        first = false
+                    }
+                    app(")")
+                }
+                is SymbolExpr -> kcode(it.getText()) // TODO
+                is TernaryExpr -> kcode("") {
+                    app("", it.getPred().toCode())
+                    app("?", it.getIfTrue().toCode())
+                    app(":", it.getIfFalse().toCode())
+                }
+                is ResourceExpr -> kcode("") {
+                    app("", it.toJava())
+                }
+                is BracketExpr -> kcode("") {
+                    app("", it.getTarget().toCode())
+                    val bracketType = it.getAccessor();
+                    when (bracketType) {
+                        BracketExpr.BracketAccessor.ARRAY -> {
+                            app("[", it.getArg().toCode())
+                            app("]")
+                        }
+                        BracketExpr.BracketAccessor.LIST -> {
+                            app(".get(")
+                            if (it.argCastsInteger()) {
+                                app("(Integer)")
+                            }
+                            app("", it.getArg().toCode())
+                            app(")")
+                        }
+                        BracketExpr.BracketAccessor.MAP -> {
+                            app(".get(", it.getArg().toCode())
+                            app(")")
+                        }
+                    }
+                }
+                is CastExpr -> kcode("") {
+                    app("(", it.getCastType())
+                    app(") ", it.getCastExpr().toCode())
+                }
+                is ArgListExpr -> throw IllegalStateException("should never try to convert an argument expressions into code");
+                else -> kcode("//NOT IMPLEMENTED YET")
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/compiler/src/main/kotlin/android/databinding/tool/writer/LayoutBinderWriter.kt b/compiler/src/main/kotlin/android/databinding/tool/writer/LayoutBinderWriter.kt
index 77605c3f..01d5f277 100644
--- a/compiler/src/main/kotlin/android/databinding/tool/writer/LayoutBinderWriter.kt
+++ b/compiler/src/main/kotlin/android/databinding/tool/writer/LayoutBinderWriter.kt
@@ -14,6 +14,8 @@
 package android.databinding.tool.writer
 
 import android.databinding.tool.LayoutBinder
+import kotlin.properties.Delegates
+import android.databinding.tool.BindingTarget
 import android.databinding.tool.expr.Expr
 import kotlin.properties.Delegates
 import android.databinding.tool.ext.joinToCamelCaseAsVar
@@ -39,8 +41,11 @@ import android.databinding.tool.ext.lazy
 import android.databinding.tool.ext.br
 import android.databinding.tool.expr.ResourceExpr
 import android.databinding.tool.expr.BracketExpr
+import android.databinding.tool.ext;
+import android.databinding.tool.util.Log
+import java.util.BitSet
+import java.util.Arrays
 import android.databinding.tool.reflection.Callable
-import android.databinding.tool.expr.CastExpr
 import android.databinding.tool.reflection.ModelAnalyzer
 import java.util.ArrayList
 import java.util.HashMap
@@ -167,96 +172,7 @@ val Expr.dirtyFlagName by Delegates.lazy { expr : Expr ->
 }
 
 
-fun Expr.toCode(full : Boolean = false) : KCode {
-    val it = this
-    if (isDynamic() && !full) {
-        return kcode(executePendingLocalName)
-    }
-    return when (it) {
-        is ComparisonExpr -> kcode("") {
-            app("", it.getLeft().toCode())
-            app(it.getOp())
-            app("", it.getRight().toCode())
-        }
-        is InstanceOfExpr -> kcode("") {
-            app("", it.getExpr().toCode())
-            app(" instanceof ")
-            app("", it.getType().toJavaCode())
-        }
-        is FieldAccessExpr -> kcode("") {
-            app("", it.getChild().toCode())
-            if (it.getGetter().type == Callable.Type.FIELD) {
-                app(".", it.getGetter().name)
-            } else {
-                app(".", it.getGetter().name).app("()")
-            }
-        }
-        is GroupExpr -> kcode("(").app("", it.getWrapped().toCode()).app(")")
-        is StaticIdentifierExpr -> kcode(it.getResolvedType().toJavaCode())
-        is IdentifierExpr -> kcode(it.executePendingLocalName)
-        is MathExpr -> kcode("") {
-            app("", it.getLeft().toCode())
-            app(it.getOp())
-            app("", it.getRight().toCode())
-        }
-        is UnaryExpr -> kcode("") {
-            app(it.getOp(), it.getExpr().toCode())
-        }
-        is BitShiftExpr -> kcode("") {
-            app("", it.getLeft().toCode())
-            app(it.getOp())
-            app("", it.getRight().toCode())
-        }
-        is MethodCallExpr -> kcode("") {
-            app("", it.getTarget().toCode())
-            app(".", it.getGetter().name)
-            app("(")
-            var first = true
-            it.getArgs().forEach {
-                apps(if (first) "" else ",", it.toCode())
-                first = false
-            }
-            app(")")
-        }
-        is SymbolExpr -> kcode(it.getText()) // TODO
-        is TernaryExpr -> kcode("") {
-            app("", it.getPred().toCode())
-            app("?", it.getIfTrue().toCode())
-            app(":", it.getIfFalse().toCode())
-        }
-        is ResourceExpr -> kcode("") {
-            app("", it.toJava())
-        }
-        is BracketExpr -> kcode("") {
-            app("", it.getTarget().toCode())
-            val bracketType = it.getAccessor();
-            when (bracketType) {
-                BracketExpr.BracketAccessor.ARRAY -> {
-                    app("[", it.getArg().toCode())
-                    app("]")
-                }
-                BracketExpr.BracketAccessor.LIST -> {
-                    app(".get(")
-                    if (it.argCastsInteger()) {
-                        app("(Integer)")
-                    }
-                    app("", it.getArg().toCode())
-                    app(")")
-                }
-                BracketExpr.BracketAccessor.MAP -> {
-                    app(".get(", it.getArg().toCode())
-                    app(")")
-                }
-            }
-        }
-        is CastExpr -> kcode("") {
-            app("(", it.getCastType())
-            app(") ", it.getCastExpr().toCode())
-        }
-        else -> kcode("//NOT IMPLEMENTED YET")
-    }
-
-}
+fun Expr.toCode(full : Boolean = false) : KCode = CodeGenUtil.toCode(this, full)
 
 fun Expr.isVariable() = this is IdentifierExpr && this.isDynamic()
 
@@ -730,7 +646,7 @@ class LayoutBinderWriter(val layoutBinder : LayoutBinder) {
                     tab("${mDirtyFlags.localValue(i)} = 0;")
                 }
             } tab("}")
-            model.getPendingExpressions().filterNot {it.isVariable()}.forEach {
+            model.getPendingExpressions().filterNot {!it.canBeEvaluatedToAVariable() || it.isVariable()}.forEach {
                 tab("${it.getResolvedType().toJavaCode()} ${it.executePendingLocalName} = ${it.getDefaultValue()};")
             }
             Log.d {"writing executePendingBindings for $className"}
@@ -772,7 +688,7 @@ class LayoutBinderWriter(val layoutBinder : LayoutBinder) {
                                 } else {
                                     fieldName = "((${binding.getTarget().getViewClass()}) this.${binding.getTarget().fieldName})"
                                 }
-                                val bindingCode = binding.toJavaCode(fieldName, binding.getExpr().toCode().generate())
+                                val bindingCode = binding.toJavaCode(fieldName)
                                 if (binding.getMinApi() > 1) {
                                     tab("if(getBuildSdkInt() >= ${binding.getMinApi()}) {") {
                                         tab("$bindingCode;")
@@ -813,7 +729,7 @@ class LayoutBinderWriter(val layoutBinder : LayoutBinder) {
         })"
 
         val readCode = kcode("") {
-            if (!expr.isVariable()) {
+            if (expr.canBeEvaluatedToAVariable() && !expr.isVariable()) {
                 // it is not a variable read it.
                 tab("// read ${expr.getUniqueKey()}")
                 // create an if case for all dependencies that might be null
diff --git a/integration-tests/TestApp/app/src/androidTest/java/android/databinding/testapp/MultiArgAdapterEvaluationTest.java b/integration-tests/TestApp/app/src/androidTest/java/android/databinding/testapp/MultiArgAdapterEvaluationTest.java
new file mode 100644
index 00000000..ac0a8ffe
--- /dev/null
+++ b/integration-tests/TestApp/app/src/androidTest/java/android/databinding/testapp/MultiArgAdapterEvaluationTest.java
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.databinding.testapp;
+
+import android.databinding.testapp.BR;
+import android.databinding.testapp.databinding.MultiArgAdapterEvaluationTestBinding;
+import android.databinding.testapp.databinding.MultiArgAdapterTestBinding;
+import android.test.UiThreadTest;
+
+import static android.databinding.testapp.adapter.MultiArgTestAdapter.MultiBindingClass1;
+import static android.databinding.testapp.adapter.MultiArgTestAdapter.MultiBindingClass2;
+import static android.databinding.testapp.adapter.MultiArgTestAdapter.join;
+
+public class MultiArgAdapterEvaluationTest extends BaseDataBinderTest<MultiArgAdapterEvaluationTestBinding> {
+
+    public MultiArgAdapterEvaluationTest() {
+        super(MultiArgAdapterEvaluationTestBinding.class);
+    }
+
+    @UiThreadTest
+    public void testMultiArgIsCalled() {
+        MultiBindingClass1 obj1 = new MultiBindingClass1();
+        MultiBindingClass2 obj2 = new MultiBindingClass2();
+        obj1.setValue("a", false);
+        obj2.setValue("b", false);
+        mBinder.setObj1(obj1);
+        mBinder.setObj2(obj2);
+        mBinder.executePendingBindings();
+
+        assertEquals(mBinder.merged.getText().toString(), join(obj1.getValue(), obj2.getValue()));
+        assertEquals(mBinder.view2.getText().toString(), join(obj2.getValue()));
+        assertEquals(mBinder.view2text.getText().toString(), obj2.getValue());
+
+        String prev2 = mBinder.view2.getText().toString();
+        String prevValue = mBinder.merged.getText().toString();
+        obj1.setValue("o", false);
+        mBinder.executePendingBindings();
+        assertEquals(prevValue, mBinder.merged.getText().toString());
+        obj2.setValue("p", false);
+        mBinder.executePendingBindings();
+        assertEquals(prevValue, mBinder.merged.getText().toString());
+        // now invalidate obj1 only, obj2 should be evaluated as well
+        obj1.setValue("o2", true);
+        mBinder.executePendingBindings();
+        assertEquals(join(obj1, obj2), mBinder.merged.getText().toString());
+        assertEquals("obj2 should not be re-evaluated", prev2, mBinder.view2.getText().toString());
+        assertEquals("obj2 should not be re-evaluated", prev2,
+                mBinder.view2text.getText().toString());
+    }
+}
diff --git a/integration-tests/TestApp/app/src/androidTest/java/android/databinding/testapp/MultiArgAdapterTest.java b/integration-tests/TestApp/app/src/androidTest/java/android/databinding/testapp/MultiArgAdapterTest.java
new file mode 100644
index 00000000..d117b9a4
--- /dev/null
+++ b/integration-tests/TestApp/app/src/androidTest/java/android/databinding/testapp/MultiArgAdapterTest.java
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.databinding.testapp;
+
+import android.databinding.testapp.adapter.MultiArgTestAdapter;
+import android.databinding.testapp.databinding.MultiArgAdapterTestBinding;
+import android.test.UiThreadTest;
+import android.view.View;
+import android.databinding.testapp.BR;
+import static android.databinding.testapp.adapter.MultiArgTestAdapter.*;
+
+public class MultiArgAdapterTest extends BaseDataBinderTest<MultiArgAdapterTestBinding> {
+
+    public MultiArgAdapterTest() {
+        super(MultiArgAdapterTestBinding.class);
+    }
+
+    @UiThreadTest
+    public void testMultiArgIsCalled() {
+        MultiBindingClass1 obj1 = new MultiBindingClass1();
+        MultiBindingClass2 obj2 = new MultiBindingClass2();
+        MultiBindingClass1 obj3 = new MultiBindingClass1();
+        MultiBindingClass2 obj4 = new MultiBindingClass2();
+        obj1.setValue("a", false);
+        obj2.setValue("b", false);
+        obj3.setValue("c", false);
+        obj4.setValue("d", false);
+        mBinder.setObj1(obj1);
+        mBinder.setObj2(obj2);
+        mBinder.setObj3(obj3);
+        mBinder.setObj4(obj4);
+        mBinder.executePendingBindings();
+
+        assertEquals(mBinder.merged.getText().toString(), join(obj1, obj2));
+        assertEquals(mBinder.view2.getText().toString(), join(obj2));
+        assertEquals(mBinder.view3.getText().toString(), join(obj3));
+        assertEquals(mBinder.view4.getText().toString(), join(obj4));
+        String prev2 = mBinder.view2.getText().toString();
+        String prevValue = mBinder.merged.getText().toString();
+        obj1.setValue("o", false);
+        mBinder.executePendingBindings();
+        assertEquals(prevValue, mBinder.merged.getText().toString());
+        obj2.setValue("p", false);
+        mBinder.executePendingBindings();
+        assertEquals(prevValue, mBinder.merged.getText().toString());
+        // now invalidate obj1 only, obj2 should be evaluated as well
+        obj1.notifyPropertyChanged(BR._all);
+        String prev3 = mBinder.view3.getText().toString();
+        String prev4 = mBinder.view4.getText().toString();
+        obj3.setValue("q", false);
+        obj4.setValue("r", false);
+        mBinder.executePendingBindings();
+        assertEquals(join(obj1, obj2), mBinder.merged.getText().toString());
+        assertEquals("obj2 should not be re-evaluated", prev2, mBinder.view2.getText().toString());
+        // make sure 3 and 4 are not invalidated
+        assertEquals("obj3 should not be re-evaluated", prev3, mBinder.view3.getText().toString());
+        assertEquals("obj4 should not be re-evaluated", prev4, mBinder.view4.getText().toString());
+
+
+    }
+
+
+}
diff --git a/integration-tests/TestApp/app/src/main/java/android/databinding/testapp/adapter/MultiArgTestAdapter.java b/integration-tests/TestApp/app/src/main/java/android/databinding/testapp/adapter/MultiArgTestAdapter.java
new file mode 100644
index 00000000..a2702798
--- /dev/null
+++ b/integration-tests/TestApp/app/src/main/java/android/databinding/testapp/adapter/MultiArgTestAdapter.java
@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.databinding.testapp.adapter;
+
+
+import android.databinding.BaseObservable;
+import android.databinding.Bindable;
+import android.databinding.BindingAdapter;
+import android.view.View;
+import android.databinding.testapp.BR;
+import android.widget.TextView;
+
+import org.apache.commons.lang3.StringUtils;
+
+public class MultiArgTestAdapter {
+
+    public static String join(BaseMultiBindingClass... classes) {
+        StringBuilder sb = new StringBuilder();
+        for(BaseMultiBindingClass instance : classes) {
+            sb.append(instance == null ? "??" : instance.getValue());
+        }
+        return sb.toString();
+    }
+
+    public static String join(String... strings) {
+        StringBuilder sb = new StringBuilder();
+        for(String str : strings) {
+            sb.append(str == null ? "??" : str);
+        }
+        return sb.toString();
+
+    }
+
+    @BindingAdapter(attributes={"android:class1", "android:class2"})
+    public static void setBoth(TextView view, MultiBindingClass1 class1,
+                                        MultiBindingClass2 class2) {
+        view.setText(join(class1, class2));
+    }
+
+    @BindingAdapter(attributes={"android:class1str", "android:class2str"})
+    public static void setBoth(TextView view, String str1,
+                               String str2) {
+        view.setText(join(str1, str2));
+    }
+
+    @BindingAdapter(attributes={"android:class1"})
+    public static void setClass1(TextView view, MultiBindingClass1 class1) {
+        view.setText(class1.getValue());
+    }
+
+    @BindingAdapter(attributes={"android:classStr"})
+    public static void setClassStr(TextView view, String str) {
+        view.setText(str);
+    }
+
+    @BindingAdapter(attributes={"android:class2"})
+    public static void setClass2(TextView view, MultiBindingClass2 class2) {
+        view.setText(class2.getValue());
+    }
+
+    public static class MultiBindingClass1 extends BaseMultiBindingClass {
+
+    }
+
+    public static class MultiBindingClass2 extends BaseMultiBindingClass {
+
+    }
+
+    public static class BaseMultiBindingClass extends BaseObservable {
+        View mSetOn;
+        @Bindable
+        String mValue;
+        public View getSetOn() {
+            return mSetOn;
+        }
+
+        public String getValue() {
+            return mValue;
+        }
+
+        public void setValue(String value, boolean notify) {
+            mValue = value;
+            if (notify) {
+                notifyPropertyChanged(BR.value);
+            }
+        }
+
+        public void clear() {
+            mSetOn = null;
+        }
+    }
+}
diff --git a/integration-tests/TestApp/app/src/main/java/android/databinding/testapp/vo/MultiAdapterSetterObj.java b/integration-tests/TestApp/app/src/main/java/android/databinding/testapp/vo/MultiAdapterSetterObj.java
new file mode 100644
index 00000000..c23a41a8
--- /dev/null
+++ b/integration-tests/TestApp/app/src/main/java/android/databinding/testapp/vo/MultiAdapterSetterObj.java
@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.databinding.testapp.vo;
+
+import android.view.View;
+
+public class MultiAdapterSetterObj {
+    public boolean isClickable;
+    public View.OnClickListener onClickListener = new View.OnClickListener() {
+        @Override
+        public void onClick(View view) {
+
+        }
+    };
+}
diff --git a/integration-tests/TestApp/app/src/main/res/layout/multi_arg_adapter_evaluation_test.xml b/integration-tests/TestApp/app/src/main/res/layout/multi_arg_adapter_evaluation_test.xml
new file mode 100644
index 00000000..2fbe6a73
--- /dev/null
+++ b/integration-tests/TestApp/app/src/main/res/layout/multi_arg_adapter_evaluation_test.xml
@@ -0,0 +1,50 @@
+<?xml version="1.0" encoding="utf-8"?><!--
+  ~ Copyright (C) 2015 The Android Open Source Project
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:bind="http://schemas.android.com/apk/res-auto">
+
+    <data>
+
+        <variable
+            name="obj1"
+            type="android.databinding.testapp.adapter.MultiArgTestAdapter.MultiBindingClass1" />
+
+        <variable
+            name="obj2"
+            type="android.databinding.testapp.adapter.MultiArgTestAdapter.MultiBindingClass2" />
+    </data>
+
+    <LinearLayout
+        android:orientation="vertical"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent">
+
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:id="@+id/merged"
+            android:class1str="@{obj1.value}"
+            android:class2str="@{obj2.value}" />
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:id="@+id/view2"
+            android:text="@{obj2.value}" />
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:id="@+id/view2text"
+            android:classStr="@{obj2.value}" />
+    </LinearLayout>
+</layout>
\ No newline at end of file
diff --git a/integration-tests/TestApp/app/src/main/res/layout/multi_arg_adapter_test.xml b/integration-tests/TestApp/app/src/main/res/layout/multi_arg_adapter_test.xml
new file mode 100644
index 00000000..fd8d4411
--- /dev/null
+++ b/integration-tests/TestApp/app/src/main/res/layout/multi_arg_adapter_test.xml
@@ -0,0 +1,66 @@
+<?xml version="1.0" encoding="utf-8"?><!--
+  ~ Copyright (C) 2015 The Android Open Source Project
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:bind="http://schemas.android.com/apk/res-auto">
+
+    <data>
+
+        <variable
+            name="obj1"
+            type="android.databinding.testapp.adapter.MultiArgTestAdapter.MultiBindingClass1" />
+
+        <variable
+            name="obj2"
+            type="android.databinding.testapp.adapter.MultiArgTestAdapter.MultiBindingClass2" />
+
+        <variable
+            name="obj3"
+            type="android.databinding.testapp.adapter.MultiArgTestAdapter.MultiBindingClass1" />
+
+        <variable
+            name="obj4"
+            type="android.databinding.testapp.adapter.MultiArgTestAdapter.MultiBindingClass2" />
+    </data>
+
+    <LinearLayout
+        android:orientation="vertical"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent">
+
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:id="@+id/merged"
+            android:class1="@{obj1}"
+            android:class2="@{obj2}" />
+
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:id="@+id/view3"
+            android:class1="@{obj3}" />
+
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:id="@+id/view4"
+            android:class2="@{obj4}" />
+
+        <TextView
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:id="@+id/view2"
+            android:class2="@{obj2}" />
+    </LinearLayout>
+</layout>
\ No newline at end of file