Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2019 IBM Corporation and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * IBM Corporation - initial API and implementation * Stephan Herrmann - Contribution for * bug 383368 - [compiler][null] syntactic null analysis for field references * Bug 392238 - [1.8][compiler][null] Detect semantically invalid null type annotations * Bug 416307 - [1.8][compiler][null] subclass with type parameter substitution confuses null checking * Bug 392099 - [1.8][compiler][null] Apply null annotation on types for null analysis * Bug 417295 - [1.8[[null] Massage type annotated null analysis to gel well with deep encoded type bindings. * Bug 392238 - [1.8][compiler][null] Detect semantically invalid null type annotations * Bug 435570 - [1.8][null] @NonNullByDefault illegally tries to affect "throws E" * Bug 466713 - Null Annotations: NullPointerException using <int @Nullable []> as Type Param * Andy Clement - Contributions for * Bug 383624 - [1.8][compiler] Revive code generation support for type annotations (from Olivier's work) *******************************************************************************/ package org.eclipse.jdt.internal.compiler.ast; import org.eclipse.jdt.internal.compiler.ASTVisitor; import org.eclipse.jdt.internal.compiler.ast.TypeReference.AnnotationPosition; import org.eclipse.jdt.internal.compiler.codegen.*; import org.eclipse.jdt.internal.compiler.flow.*; import org.eclipse.jdt.internal.compiler.impl.Constant; import org.eclipse.jdt.internal.compiler.lookup.*; public class InstanceOfExpression extends OperatorExpression { public Expression expression; public TypeReference type; public InstanceOfExpression(Expression expression, TypeReference type) { this.expression = expression; this.type = type; type.bits |= IgnoreRawTypeCheck; // https://bugs.eclipse.org/bugs/show_bug.cgi?id=282141 this.bits |= INSTANCEOF << OperatorSHIFT; this.sourceStart = expression.sourceStart; this.sourceEnd = type.sourceEnd; } @Override public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) { LocalVariableBinding local = this.expression.localVariableBinding(); if (local != null && (local.type.tagBits & TagBits.IsBaseType) == 0) { flowInfo = this.expression.analyseCode(currentScope, flowContext, flowInfo).unconditionalInits(); FlowInfo initsWhenTrue = flowInfo.copy(); initsWhenTrue.markAsComparedEqualToNonNull(local); flowContext.recordUsingNullReference(currentScope, local, this.expression, FlowContext.CAN_ONLY_NULL | FlowContext.IN_INSTANCEOF, flowInfo); // no impact upon enclosing try context return FlowInfo.conditional(initsWhenTrue, flowInfo.copy()); } if (this.expression instanceof Reference && currentScope.compilerOptions().enableSyntacticNullAnalysisForFields) { FieldBinding field = ((Reference) this.expression).lastFieldBinding(); if (field != null && (field.type.tagBits & TagBits.IsBaseType) == 0) { flowContext.recordNullCheckedFieldReference((Reference) this.expression, 1); } } return this.expression.analyseCode(currentScope, flowContext, flowInfo).unconditionalInits(); } /** * Code generation for instanceOfExpression * * @param currentScope org.eclipse.jdt.internal.compiler.lookup.BlockScope * @param codeStream org.eclipse.jdt.internal.compiler.codegen.CodeStream * @param valueRequired boolean */ @Override public void generateCode(BlockScope currentScope, CodeStream codeStream, boolean valueRequired) { int pc = codeStream.position; this.expression.generateCode(currentScope, codeStream, true); codeStream.instance_of(this.type, this.type.resolvedType); if (valueRequired) { codeStream.generateImplicitConversion(this.implicitConversion); } else { codeStream.pop(); } codeStream.recordPositionsFrom(pc, this.sourceStart); } @Override public StringBuffer printExpressionNoParenthesis(int indent, StringBuffer output) { this.expression.printExpression(indent, output).append(" instanceof "); //$NON-NLS-1$ return this.type.print(0, output); } @Override public TypeBinding resolveType(BlockScope scope) { this.constant = Constant.NotAConstant; TypeBinding checkedType = this.type.resolveType(scope, true /* check bounds*/); if (this.expression instanceof CastExpression) { ((CastExpression) this.expression).setInstanceofType(checkedType); // for cast expression we need to know instanceof type to not tag unnecessary when needed } TypeBinding expressionType = this.expression.resolveType(scope); if (expressionType != null && checkedType != null && this.type.hasNullTypeAnnotation(AnnotationPosition.ANY)) { // don't complain if the entire operation is redundant anyway if (!expressionType.isCompatibleWith(checkedType) || NullAnnotationMatching.analyse(checkedType, expressionType, -1).isAnyMismatch()) scope.problemReporter().nullAnnotationUnsupportedLocation(this.type); } if (expressionType == null || checkedType == null) return null; if (!checkedType.isReifiable()) { scope.problemReporter().illegalInstanceOfGenericType(checkedType, this); } else if (checkedType.isValidBinding()) { // if not a valid binding, an error has already been reported for unresolved type if ((expressionType != TypeBinding.NULL && expressionType.isBaseType()) // disallow autoboxing || !checkCastTypesCompatibility(scope, checkedType, expressionType, null)) { scope.problemReporter().notCompatibleTypesError(this, expressionType, checkedType); } } return this.resolvedType = TypeBinding.BOOLEAN; } /** * @see org.eclipse.jdt.internal.compiler.ast.Expression#tagAsUnnecessaryCast(Scope,TypeBinding) */ @Override public void tagAsUnnecessaryCast(Scope scope, TypeBinding castType) { // null is not instanceof Type, recognize direct scenario if (this.expression.resolvedType != TypeBinding.NULL) scope.problemReporter().unnecessaryInstanceof(this, castType); } @Override public void traverse(ASTVisitor visitor, BlockScope scope) { if (visitor.visit(this, scope)) { this.expression.traverse(visitor, scope); this.type.traverse(visitor, scope); } visitor.endVisit(this, scope); } }