Merge pull request #2994 from jlerbsc/polyexpression

Adding management of the poly and standalone expression
javaparser · Dec 27, 2020 · 54496f6 · 54496f6
2 parents 1f193dd + e3b2a2d
commit 54496f6
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Showing 15 changed files with 448 additions and 245 deletions.
diff --git a/javaparser-core/src/main/java/com/github/javaparser/ast/expr/AssignExpr.java b/javaparser-core/src/main/java/com/github/javaparser/ast/expr/AssignExpr.java
@@ -20,20 +20,22 @@
  */
 package com.github.javaparser.ast.expr;
 
+import static com.github.javaparser.utils.Utils.assertNotNull;
+
+import java.util.Optional;
+import java.util.function.Consumer;
+
+import com.github.javaparser.TokenRange;
 import com.github.javaparser.ast.AllFieldsConstructor;
+import com.github.javaparser.ast.Generated;
+import com.github.javaparser.ast.Node;
 import com.github.javaparser.ast.observer.ObservableProperty;
+import com.github.javaparser.ast.visitor.CloneVisitor;
 import com.github.javaparser.ast.visitor.GenericVisitor;
 import com.github.javaparser.ast.visitor.VoidVisitor;
-import static com.github.javaparser.utils.Utils.assertNotNull;
-import com.github.javaparser.ast.Node;
-import com.github.javaparser.ast.visitor.CloneVisitor;
 import com.github.javaparser.metamodel.AssignExprMetaModel;
 import com.github.javaparser.metamodel.JavaParserMetaModel;
 import com.github.javaparser.printer.Stringable;
-import com.github.javaparser.TokenRange;
-import java.util.function.Consumer;
-import java.util.Optional;
-import com.github.javaparser.ast.Generated;
 
 /**
  * An assignment expression. It supports the operators that are found the the AssignExpr.Operator enum.
@@ -253,4 +255,14 @@ public void ifAssignExpr(Consumer<AssignExpr> action) {
     public Optional<AssignExpr> toAssignExpr() {
         return Optional.of(this);
     }
+
+    /*
+     * Returns true if the expression is an assignment context
+     * https://docs.oracle.com/javase/specs/jls/se8/html/jls-5.html#jls-5.2
+     * 5.2. Assignment Contexts: Assignment contexts allow the value of an expression to be assigned (§15.26) to a variable;...
+     */
+    @Override
+    protected boolean isAssignmentContext() {
+        return true;
+    }
 }
diff --git a/javaparser-core/src/main/java/com/github/javaparser/ast/expr/ConditionalExpr.java b/javaparser-core/src/main/java/com/github/javaparser/ast/expr/ConditionalExpr.java
@@ -20,20 +20,22 @@
  */
 package com.github.javaparser.ast.expr;
 
+import static com.github.javaparser.utils.Utils.assertNotNull;
+
+import java.util.Optional;
+import java.util.function.Consumer;
+
+import com.github.javaparser.TokenRange;
 import com.github.javaparser.ast.AllFieldsConstructor;
+import com.github.javaparser.ast.Generated;
+import com.github.javaparser.ast.Node;
 import com.github.javaparser.ast.nodeTypes.NodeWithCondition;
 import com.github.javaparser.ast.observer.ObservableProperty;
+import com.github.javaparser.ast.visitor.CloneVisitor;
 import com.github.javaparser.ast.visitor.GenericVisitor;
 import com.github.javaparser.ast.visitor.VoidVisitor;
-import static com.github.javaparser.utils.Utils.assertNotNull;
-import com.github.javaparser.ast.Node;
-import com.github.javaparser.ast.visitor.CloneVisitor;
 import com.github.javaparser.metamodel.ConditionalExprMetaModel;
 import com.github.javaparser.metamodel.JavaParserMetaModel;
-import com.github.javaparser.TokenRange;
-import java.util.function.Consumer;
-import java.util.Optional;
-import com.github.javaparser.ast.Generated;
 
 /**
  * The ternary conditional expression.
@@ -201,4 +203,13 @@ public void ifConditionalExpr(Consumer<ConditionalExpr> action) {
     public Optional<ConditionalExpr> toConditionalExpr() {
         return Optional.of(this);
     }
+
+    /*
+     * A reference conditional expression is a poly expression if it appears in an assignment context or an invocation context (§5.2. §5.3). 
+     * Otherwise, it is a standalone expression.
+     */
+    @Override
+    public boolean isPolyExpression() {
+        return appearsInAssignmentContext() || appearsInInvocationContext();
+    }
 }
diff --git a/javaparser-core/src/main/java/com/github/javaparser/ast/expr/EnclosedExpr.java b/javaparser-core/src/main/java/com/github/javaparser/ast/expr/EnclosedExpr.java
@@ -20,19 +20,21 @@
  */
 package com.github.javaparser.ast.expr;
 
+import static com.github.javaparser.utils.Utils.assertNotNull;
+
+import java.util.Optional;
+import java.util.function.Consumer;
+
+import com.github.javaparser.TokenRange;
 import com.github.javaparser.ast.AllFieldsConstructor;
+import com.github.javaparser.ast.Generated;
+import com.github.javaparser.ast.Node;
 import com.github.javaparser.ast.observer.ObservableProperty;
+import com.github.javaparser.ast.visitor.CloneVisitor;
 import com.github.javaparser.ast.visitor.GenericVisitor;
 import com.github.javaparser.ast.visitor.VoidVisitor;
-import java.util.Optional;
-import com.github.javaparser.ast.Node;
-import com.github.javaparser.ast.visitor.CloneVisitor;
 import com.github.javaparser.metamodel.EnclosedExprMetaModel;
 import com.github.javaparser.metamodel.JavaParserMetaModel;
-import com.github.javaparser.TokenRange;
-import static com.github.javaparser.utils.Utils.assertNotNull;
-import java.util.function.Consumer;
-import com.github.javaparser.ast.Generated;
 
 /**
  * An expression between ( ).
@@ -154,4 +156,13 @@ public void ifEnclosedExpr(Consumer<EnclosedExpr> action) {
     public Optional<EnclosedExpr> toEnclosedExpr() {
         return Optional.of(this);
     }
+
+    /*
+     * On Parenthesized Expressions, if the contained expression is a poly expression (§15.2), the parenthesized expression is also a poly expression. Otherwise, it is a standalone expression.
+     * (https://docs.oracle.com/javase/specs/jls/se8/html/jls-15.html#jls-15.8.5)
+     */
+    @Override
+    public boolean isPolyExpression() {
+        return getInner().isPolyExpression();
+    }
 }
diff --git a/javaparser-core/src/main/java/com/github/javaparser/ast/expr/Expression.java b/javaparser-core/src/main/java/com/github/javaparser/ast/expr/Expression.java
@@ -20,17 +20,21 @@
  */
 package com.github.javaparser.ast.expr;
 
+import static com.github.javaparser.utils.CodeGenerationUtils.f;
+
+import java.util.Optional;
+import java.util.function.Consumer;
+
+import com.github.javaparser.TokenRange;
 import com.github.javaparser.ast.AllFieldsConstructor;
+import com.github.javaparser.ast.Generated;
 import com.github.javaparser.ast.Node;
+import com.github.javaparser.ast.nodeTypes.NodeWithOptionalScope;
+import com.github.javaparser.ast.nodeTypes.NodeWithTypeArguments;
 import com.github.javaparser.ast.visitor.CloneVisitor;
 import com.github.javaparser.metamodel.ExpressionMetaModel;
 import com.github.javaparser.metamodel.JavaParserMetaModel;
-import com.github.javaparser.TokenRange;
 import com.github.javaparser.resolution.types.ResolvedType;
-import com.github.javaparser.ast.Generated;
-import java.util.function.Consumer;
-import static com.github.javaparser.utils.CodeGenerationUtils.f;
-import java.util.Optional;
 
 /**
  * A base class for all expressions.
@@ -790,4 +794,87 @@ public Optional<PatternExpr> toPatternExpr() {
     @Generated("com.github.javaparser.generator.core.node.TypeCastingGenerator")
     public void ifPatternExpr(Consumer<PatternExpr> action) {
     }
+
+    /**
+     * See https://docs.oracle.com/javase/specs/jls/se8/html/jls-15.html#jls-15.2
+     * @return true if the expression is a standalone expression
+     */
+    public boolean isStandaloneExpression() {
+        return !isPolyExpression();
+    }
+
+    /**
+     * See https://docs.oracle.com/javase/specs/jls/se8/html/jls-15.html#jls-15.2
+     * @return true if the expression is a poly expression
+     */
+    public boolean isPolyExpression() {
+        return false;
+    }
+
+    /*
+     * 6.5.6.2. Qualified Expression Names
+     * https://docs.oracle.com/javase/specs/jls/se7/html/jls-6.html#jls-6.5.6.2
+     */
+    public boolean isQualified() {
+        return this instanceof NodeWithOptionalScope && ((NodeWithOptionalScope)this).getScope().isPresent();
+    }
+
+    /*
+     * Verify if the parent node is an assignment context. 
+     */
+    public final boolean appearsInAssignmentContext() {
+        if (getParentNode().isPresent() && getParentNode().get() instanceof Expression) {
+            return ((Expression)getParentNode().get()).isAssignmentContext();
+        }
+        return false;
+    }
+
+    /*
+     * Returns true if the expression is an assignment context. Default is false.
+     * https://docs.oracle.com/javase/specs/jls/se8/html/jls-5.html#jls-5.2
+     * 5.2. Assignment Contexts: Assignment contexts allow the value of an expression to be assigned (§15.26) to a variable;...
+     */
+    protected boolean isAssignmentContext() {
+        return false;
+    }
+
+    /*
+     * Verify if the parent node is an invocation context. 
+     */
+    public final boolean appearsInInvocationContext() {
+        if (getParentNode().isPresent() && getParentNode().get() instanceof Expression) {
+            return ((Expression)getParentNode().get()).isInvocationContext();
+        }
+        return false;
+    }
+
+    /*
+     * Returns true if the expression is an invocation context. Default is false.
+     * https://docs.oracle.com/javase/specs/jls/se8/html/jls-5.html#jls-5.3
+     * 5.3. Invocation Contexts
+     */
+    protected boolean isInvocationContext() {
+        return false;
+    }
+
+    /*
+     * returns true if the scope of this expression does not define an type argument or if the expression has not a scope (the expression is not qualified) 
+     * or if there is a scope it uses <> to elide class type arguments
+     * For exemple :
+     * m()      ==> true because there is no scope
+     * a.m()    ==> true because the scope has no type arguments
+     * a<>.m()  ==> true because the type argument is elided
+     * a<T>.m() ==> false because the type argument is not elided
+     */
+    public final boolean elidesTypeArguments() {
+        if (!(this instanceof NodeWithOptionalScope 
+                && ((NodeWithOptionalScope) this).getScope().isPresent()
+                && this instanceof NodeWithTypeArguments)) {
+            return true;
+        }
+        Expression scope = (Expression) ((NodeWithOptionalScope) this).getScope().get();
+        NodeWithTypeArguments nwta = (NodeWithTypeArguments)this;
+        return scope.elidesTypeArguments() 
+                && (!nwta.getTypeArguments().isPresent() || nwta.isUsingDiamondOperator());
+    }
 }
diff --git a/javaparser-core/src/main/java/com/github/javaparser/ast/expr/LambdaExpr.java b/javaparser-core/src/main/java/com/github/javaparser/ast/expr/LambdaExpr.java
@@ -20,6 +20,11 @@
  */
 package com.github.javaparser.ast.expr;
 
+import static com.github.javaparser.utils.Utils.assertNotNull;
+
+import java.util.Optional;
+import java.util.function.Consumer;
+
 import com.github.javaparser.TokenRange;
 import com.github.javaparser.ast.AllFieldsConstructor;
 import com.github.javaparser.ast.Generated;
@@ -38,9 +43,6 @@
 import com.github.javaparser.metamodel.DerivedProperty;
 import com.github.javaparser.metamodel.JavaParserMetaModel;
 import com.github.javaparser.metamodel.LambdaExprMetaModel;
-import java.util.Optional;
-import java.util.function.Consumer;
-import static com.github.javaparser.utils.Utils.assertNotNull;
 
 /**
  * <h1>A lambda expression</h1>
@@ -262,4 +264,12 @@ public void ifLambdaExpr(Consumer<LambdaExpr> action) {
     public Optional<LambdaExpr> toLambdaExpr() {
         return Optional.of(this);
     }
+
+    /*
+     * Lambda expressions are always poly expressions
+     */
+    @Override
+    public boolean isPolyExpression() {
+        return true;
+    }
 }
diff --git a/javaparser-core/src/main/java/com/github/javaparser/ast/expr/MethodCallExpr.java b/javaparser-core/src/main/java/com/github/javaparser/ast/expr/MethodCallExpr.java
@@ -20,7 +20,15 @@
  */
 package com.github.javaparser.ast.expr;
 
+import static com.github.javaparser.utils.Utils.assertNotNull;
+
+import java.util.Optional;
+import java.util.function.Consumer;
+
+import com.github.javaparser.TokenRange;
 import com.github.javaparser.ast.AllFieldsConstructor;
+import com.github.javaparser.ast.Generated;
+import com.github.javaparser.ast.Node;
 import com.github.javaparser.ast.NodeList;
 import com.github.javaparser.ast.nodeTypes.NodeWithArguments;
 import com.github.javaparser.ast.nodeTypes.NodeWithOptionalScope;
@@ -29,21 +37,16 @@
 import com.github.javaparser.ast.observer.ObservableProperty;
 import com.github.javaparser.ast.stmt.ExplicitConstructorInvocationStmt;
 import com.github.javaparser.ast.type.Type;
+import com.github.javaparser.ast.visitor.CloneVisitor;
 import com.github.javaparser.ast.visitor.GenericVisitor;
 import com.github.javaparser.ast.visitor.VoidVisitor;
-import java.util.Optional;
-import static com.github.javaparser.utils.Utils.assertNotNull;
-import com.github.javaparser.ast.Node;
-import com.github.javaparser.ast.visitor.CloneVisitor;
-import com.github.javaparser.metamodel.MethodCallExprMetaModel;
 import com.github.javaparser.metamodel.JavaParserMetaModel;
-import com.github.javaparser.TokenRange;
+import com.github.javaparser.metamodel.MethodCallExprMetaModel;
 import com.github.javaparser.metamodel.OptionalProperty;
 import com.github.javaparser.resolution.Resolvable;
 import com.github.javaparser.resolution.UnsolvedSymbolException;
 import com.github.javaparser.resolution.declarations.ResolvedMethodDeclaration;
-import java.util.function.Consumer;
-import com.github.javaparser.ast.Generated;
+import com.github.javaparser.resolution.types.ResolvedType;
 
 /**
  * A method call on an object or a class. <br>{@code circle.circumference()} <br>In <code>a.&lt;String&gt;bb(15);</code> a
@@ -318,4 +321,68 @@ public ResolvedMethodDeclaration resolve() {
     public Optional<MethodCallExpr> toMethodCallExpr() {
         return Optional.of(this);
     }
+
+    /*
+     * A method invocation expression is a poly expression if all of the following are true:
+     * 1. The invocation appears in an assignment context or an invocation context (§5.2, §5.3).
+     * 2. If the invocation is qualified (that is, any form of MethodInvocation except for the first), then
+     *    the invocation elides TypeArguments to the left of the Identifier.
+     * 3. The method to be invoked, as determined by the following subsections, is generic (§8.4.4) and has a
+     *    return type that mentions at least one of the method's type parameters.
+     * Otherwise, the method invocation expression is a standalone expression.
+     */
+    @Override
+    public boolean isPolyExpression() {
+        // A method invocation expression is a poly expression if all of the following are true:
+        //
+        // 1. The invocation appears in an assignment context or an invocation context (§5.2, §5.3).
+
+        if (!(appearsInAssignmentContext() || appearsInInvocationContext())) {
+            return false;
+        }
+
+        // 2. If the invocation is qualified (that is, any form of MethodInvocation except for the form [MethodName (
+        // [ArgumentList] )]), then the invocation elides TypeArguments to the left of the Identifier.
+
+        if (isQualified() && !elidesTypeArguments()) {
+            return false;
+        }
+
+        // 3. The method to be invoked, as determined by the following subsections, is generic (§8.4.4) and has a
+        // return type that mentions at least one of the method's type parameters.
+        // A method is generic if it declares one or more type variables (§4.4).
+        if (isGenericMethod() && hasParameterwithSameTypeThanResultType(resolve().getReturnType())) {
+            return true; // it's a poly expression
+        }
+
+        // Otherwise, the method invocation expression is a standalone expression.
+         return false;
+    }
+
+    /*
+     *  A method is generic if it declares one or more type variables (§4.4).
+     *  Not sure it's enough to verify that the type arguments list is empty or not.
+     */
+    private boolean isGenericMethod() {
+        return getTypeArguments().isPresent() && !getTypeArguments().get().isEmpty();
+    }
+
+    /*
+     *  return true if at least one of the method's type parameters has the same type as the specified type .
+     */
+    private boolean hasParameterwithSameTypeThanResultType(ResolvedType resolvedReturnType) {
+        return getTypeArguments().isPresent() && getTypeArguments().get().stream().anyMatch(argType -> argType.resolve().isAssignableBy(resolvedReturnType));
+    }
+
+
+
+    /*
+     * Returns true if the expression is an invocation context.
+     * https://docs.oracle.com/javase/specs/jls/se8/html/jls-5.html#jls-5.3
+     * 5.3. Invocation Contexts
+     */
+    @Override
+    protected boolean isInvocationContext() {
+        return true;
+    }
 }