Context.java
/*
* Copyright (C) 2015-2016 Federico Tomassetti
* Copyright (C) 2017-2023 The JavaParser Team.
*
* This file is part of JavaParser.
*
* JavaParser can be used either under the terms of
* a) the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
* b) the terms of the Apache License
*
* You should have received a copy of both licenses in LICENCE.LGPL and
* LICENCE.APACHE. Please refer to those files for details.
*
* JavaParser is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*/
package com.github.javaparser.resolution;
import com.github.javaparser.ast.Node;
import com.github.javaparser.ast.body.Parameter;
import com.github.javaparser.ast.body.VariableDeclarator;
import com.github.javaparser.ast.expr.PatternExpr;
import com.github.javaparser.quality.Nullable;
import com.github.javaparser.resolution.declarations.*;
import com.github.javaparser.resolution.model.SymbolReference;
import com.github.javaparser.resolution.model.Value;
import com.github.javaparser.resolution.types.ResolvedType;
import java.util.Collections;
import java.util.List;
import java.util.Optional;
/**
* Context is very similar to scope.
* In the context we look for solving symbols.
*
* @author Federico Tomassetti
*/
public interface Context {
/**
* Returns the node wrapped in the context
*
*/
<N extends Node> N getWrappedNode();
/**
* @return The parent context, if there is one. For example, a method exists within a compilation unit.
*/
Optional<Context> getParent();
/* Type resolution */
/**
* Default to no generics available in this context, delegating solving to the parent context.
* Contexts which have generics available to it will override this method.
* For example class and method declarations, and method calls.
*
* @param name For example, solving {@code T} within {@code class Foo<T> {}} or
* @return The resolved generic type, if found.
*/
default Optional<ResolvedType> solveGenericType(String name) {
// Default to solving within the parent context.
return solveGenericTypeInParentContext(name);
}
default Optional<ResolvedType> solveGenericTypeInParentContext(String name) {
Optional<Context> optionalParentContext = getParent();
if (!optionalParentContext.isPresent()) {
return Optional.empty();
}
// Delegate solving to the parent context.
return optionalParentContext.get().solveGenericType(name);
}
/**
* Default to being unable to solve any reference in this context, delegating solving to the parent context.
* Contexts which exist as the "parent" of a resolvable type will override this method.
* For example, a compilation unit can contain classes. A class declaration can also contain types (e.g. a subclass).
*
* @param name For example, solving {@code List} or {@code java.util.List}.
* @return The declaration associated with the given type name.
*
* @deprecated Consider using method {@link #solveType(String, List)} that also consider the type arguments.
* If you want to keep to use the new function, but keep the same behavior consider passing type
* arguments as {@code null}.
*/
@Deprecated
default SymbolReference<ResolvedTypeDeclaration> solveType(String name) {
return solveType(name, null);
}
/**
* Method used to solve a name with an expected list of type arguments.
* <br>
* This method differs from {@link Context#solveType(String)} by taking the type arguments in consideration.
* For example, lets imagine that we have a project containing the following classes:
* <ul>
* <li>com/example/Alpha.java</li>
* <li>com/example/Beta.java</li>
* </ul>
* Where Alpha creates a inner interface called CustomInterface and Beta implements Alpha.CustomInterface and
* also declares a inner interface called CustomInterface with type arguments. Using this method we can
* specify which type arguments we are expecting and will be resolved with the type matching that declaration.
*
* @param name The name to be solved.
* @param typeArguments The list of expected type arguments.
*
* @return The declaration associated with the given type name.
*/
default SymbolReference<ResolvedTypeDeclaration> solveType(String name, @Nullable List<ResolvedType> typeArguments) {
// Default to solving within the parent context.
return solveTypeInParentContext(name, typeArguments);
}
/**
* Solve a name in the parent context.
*
* @param name The name to be solved.
*
* @return The declaration associated with the given type name.
*
* @deprecated Consider using method {@link #solveTypeInParentContext(String, List)} that also consider the type arguments.
* If you want to keep to use the new function, but keep the same behavior consider passing type
* arguments as {@code null}.
*/
@Deprecated
default SymbolReference<ResolvedTypeDeclaration> solveTypeInParentContext(String name) {
return solveTypeInParentContext(name, null);
}
/**
* Solve a name with type arguments in the parent context.
*
* @param name The name to be solved.
* @param typeArguments The list of expected type arguments.
*
* @return The declaration associated with the given type name.
*/
default SymbolReference<ResolvedTypeDeclaration> solveTypeInParentContext(String name, @Nullable List<ResolvedType> typeArguments) {
Optional<Context> optionalParentContext = getParent();
if (!optionalParentContext.isPresent()) {
return SymbolReference.unsolved();
}
// Delegate solving to the parent context.
return optionalParentContext.get().solveType(name, typeArguments);
}
/* Symbol resolution */
/**
* Used where a symbol is being used (e.g. solving {@code x} when used as an argument {@code doubleThis(x)}, or calculation {@code return x * 2;}).
* @param name the variable / reference / identifier used.
* @return // FIXME: Better documentation on how this is different to solveSymbolAsValue()
*/
default SymbolReference<? extends ResolvedValueDeclaration> solveSymbol(String name) {
// Default to solving within the parent context.
return solveSymbolInParentContext(name);
}
default SymbolReference<? extends ResolvedValueDeclaration> solveSymbolInParentContext(String name) {
Optional<Context> optionalParentContext = getParent();
if (!optionalParentContext.isPresent()) {
return SymbolReference.unsolved();
}
// Delegate solving to the parent context.
return optionalParentContext.get().solveSymbol(name);
}
/**
* Used where a symbol is being used (e.g. solving {@code x} when used as an argument {@code doubleThis(x)}, or calculation {@code return x * 2;}).
* @param name the variable / reference / identifier used.
* @return // FIXME: Better documentation on how this is different to solveSymbol()
*/
default Optional<Value> solveSymbolAsValue(String name) {
SymbolReference<? extends ResolvedValueDeclaration> ref = solveSymbol(name);
if (!ref.isSolved()) {
return Optional.empty();
}
return Optional.of(Value.from(ref.getCorrespondingDeclaration()));
}
default Optional<Value> solveSymbolAsValueInParentContext(String name) {
SymbolReference<? extends ResolvedValueDeclaration> ref = solveSymbolInParentContext(name);
if (!ref.isSolved()) {
return Optional.empty();
}
return Optional.of(Value.from(ref.getCorrespondingDeclaration()));
}
/**
* The fields that are declared and in this immediate context made visible to a given child.
* This list could include values which are shadowed.
*/
default List<ResolvedFieldDeclaration> fieldsExposedToChild(Node child) {
return Collections.emptyList();
}
/**
* The local variables that are declared in this immediate context and made visible to a given child.
* This list could include values which are shadowed.
*/
default List<VariableDeclarator> localVariablesExposedToChild(Node child) {
return Collections.emptyList();
}
/**
* The parameters that are declared in this immediate context and made visible to a given child.
* This list could include values which are shadowed.
*/
default List<Parameter> parametersExposedToChild(Node child) {
return Collections.emptyList();
}
/**
* The pattern expressions that are declared in this immediate context and made visible to a given child.
* This list could include values which are shadowed.
*/
default List<PatternExpr> patternExprsExposedToChild(Node child) {
return Collections.emptyList();
}
/**
*/
default List<PatternExpr> patternExprsExposedFromChildren() {
return Collections.emptyList();
}
/**
*/
default List<PatternExpr> negatedPatternExprsExposedFromChildren() {
return Collections.emptyList();
}
/**
* Aim to resolve the given name by looking for a variable matching it.
* <p>
* To do it consider local variables that are visible in a certain scope as defined in JLS 6.3. Scope of a
* Declaration.
* <p>
* 1. The scope of a local variable declaration in a block (��14.4) is the rest of the block in which the
* declaration
* appears, starting with its own initializer and including any further declarators to the right in the local
* variable declaration statement.
* <p>
* 2. The scope of a local variable declared in the ForInit part of a basic for statement (��14.14.1) includes all
* of the following:
* 2.1 Its own initializer
* 2.2 Any further declarators to the right in the ForInit part of the for statement
* 2.3 The Expression and ForUpdate parts of the for statement
* 2.4 The contained Statement
* <p>
* 3. The scope of a local variable declared in the FormalParameter part of an enhanced for statement (��14.14.2) is
* the contained Statement.
* 4. The scope of a parameter of an exception handler that is declared in a catch clause of a try statement
* (��14.20) is the entire block associated with the catch.
* <p>
* 5. The scope of a variable declared in the ResourceSpecification of a try-with-resources statement (��14.20.3) is
* from the declaration rightward over the remainder of the ResourceSpecification and the entire try block
* associated with the try-with-resources statement.
*/
default Optional<VariableDeclarator> localVariableDeclarationInScope(String name) {
if (!getParent().isPresent()) {
return Optional.empty();
}
// First check if the variable is directly declared within this context.
Node wrappedNode = getWrappedNode();
Context parentContext = getParent().get();
Optional<VariableDeclarator> localResolutionResults = parentContext
.localVariablesExposedToChild(wrappedNode)
.stream()
.filter(vd -> vd.getNameAsString().equals(name))
.findFirst();
if (localResolutionResults.isPresent()) {
return localResolutionResults;
}
// If we don't find the variable locally, escalate up the scope hierarchy to see if it is declared there.
return parentContext.localVariableDeclarationInScope(name);
}
default Optional<Parameter> parameterDeclarationInScope(String name) {
if (!getParent().isPresent()) {
return Optional.empty();
}
// First check if the parameter is directly declared within this context.
Node wrappedNode = getWrappedNode();
Context parentContext = getParent().get();
Optional<Parameter> localResolutionResults = parentContext
.parametersExposedToChild(wrappedNode)
.stream()
.filter(vd -> vd.getNameAsString().equals(name))
.findFirst();
if (localResolutionResults.isPresent()) {
return localResolutionResults;
}
// If we don't find the parameter locally, escalate up the scope hierarchy to see if it is declared there.
return parentContext.parameterDeclarationInScope(name);
}
/**
* With respect to solving, the AST "parent" of a block statement is not necessarily the same as the scope parent.
* <br>Example:
* <br>
* <pre>{@code
* public String x() {
* if(x) {
* // Parent node: the block attached to the method declaration
* // Scope-parent: the block attached to the method declaration
* } else if {
* // Parent node: the if
* // Scope-parent: the block attached to the method declaration
* } else {
* // Parent node: the elseif
* // Scope-parent: the block attached to the method declaration
* }
* }
* }</pre>
*/
default Optional<PatternExpr> patternExprInScope(String name) {
if (!getParent().isPresent()) {
return Optional.empty();
}
Context parentContext = getParent().get();
// FIXME: "scroll backwards" from the wrapped node
// FIXME: If there are multiple patterns, throw an error?
// First check if the pattern is directly declared within this context.
Node wrappedNode = getWrappedNode();
Optional<PatternExpr> localResolutionResults = parentContext
.patternExprsExposedToChild(wrappedNode)
.stream()
.filter(vd -> vd.getNameAsString().equals(name))
.findFirst();
if (localResolutionResults.isPresent()) {
return localResolutionResults;
}
// If we don't find the parameter locally, escalate up the scope hierarchy to see if it is declared there.
return parentContext.patternExprInScope(name);
}
default Optional<ResolvedFieldDeclaration> fieldDeclarationInScope(String name) {
if (!getParent().isPresent()) {
return Optional.empty();
}
Context parentContext = getParent().get();
// First check if the parameter is directly declared within this context.
Node wrappedNode = getWrappedNode();
Optional<ResolvedFieldDeclaration> localResolutionResults = parentContext
.fieldsExposedToChild(wrappedNode)
.stream()
.filter(vd -> vd.getName().equals(name))
.findFirst();
if (localResolutionResults.isPresent()) {
return localResolutionResults;
}
// If we don't find the field locally, escalate up the scope hierarchy to see if it is declared there.
return parentContext.fieldDeclarationInScope(name);
}
/* Constructor resolution */
/**
* We find the method declaration which is the best match for the given name and list of typeParametersValues.
*/
default SymbolReference<ResolvedConstructorDeclaration> solveConstructor(List<ResolvedType> argumentsTypes) {
throw new IllegalArgumentException("Constructor resolution is available only on Class Context");
}
/* Methods resolution */
/**
* We find the method declaration which is the best match for the given name and list of typeParametersValues.
*/
default SymbolReference<ResolvedMethodDeclaration> solveMethod(String name, List<ResolvedType> argumentsTypes, boolean staticOnly) {
// Default to solving within the parent context.
return solveMethodInParentContext(name, argumentsTypes, staticOnly);
}
default SymbolReference<ResolvedMethodDeclaration> solveMethodInParentContext(String name, List<ResolvedType> argumentsTypes, boolean staticOnly) {
Optional<Context> optionalParentContext = getParent();
if (!optionalParentContext.isPresent()) {
return SymbolReference.unsolved();
}
// Delegate solving to the parent context.
return optionalParentContext.get().solveMethod(name, argumentsTypes, staticOnly);
}
/**
* Similar to solveMethod but we return a MethodUsage.
* A MethodUsage corresponds to a MethodDeclaration plus the resolved type variables.
*/
Optional<MethodUsage> solveMethodAsUsage(String name, List<ResolvedType> argumentsTypes);
}