org.eclipse.jdt.core.dom.Expression Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2000, 2013 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.jdt.core.dom;
/**
* Abstract base class of AST nodes that represent expressions.
* There are several kinds of expressions.
*
*
* Expression:
* {@link Annotation},
* {@link ArrayAccess},
* {@link ArrayCreation},
* {@link ArrayInitializer},
* {@link Assignment},
* {@link BooleanLiteral},
* {@link CastExpression},
* {@link CharacterLiteral},
* {@link ClassInstanceCreation},
* {@link ConditionalExpression},
* {@link CreationReference},
* {@link ExpressionMethodReference},
* {@link FieldAccess},
* {@link InfixExpression},
* {@link InstanceofExpression},
* {@link LambdaExpression},
* {@link MethodInvocation},
* {@link MethodReference},
* {@link Name},
* {@link NullLiteral},
* {@link NumberLiteral},
* {@link ParenthesizedExpression},
* {@link PostfixExpression},
* {@link PrefixExpression},
* {@link StringLiteral},
* {@link SuperFieldAccess},
* {@link SuperMethodInvocation},
* {@link SuperMethodReference},
* {@link ThisExpression},
* {@link TypeLiteral},
* {@link TypeMethodReference},
* {@link VariableDeclarationExpression}
*
*
*
* @since 2.0
*/
public abstract class Expression extends ASTNode {
/**
* Creates a new AST node for an expression owned by the given AST.
*
* N.B. This constructor is package-private.
*
*
* @param ast the AST that is to own this node
*/
Expression(AST ast) {
super(ast);
}
/**
* Resolves and returns the compile-time constant expression value as
* specified in JLS2 15.28, if this expression has one. Constant expression
* values are unavailable unless bindings are requested when the AST is
* being built. If the type of the value is a primitive type, the result
* is the boxed equivalent (i.e., int returned as an Integer);
* if the type of the value is String, the result is the string
* itself. If the expression does not have a compile-time constant expression
* value, the result is null.
*
* Resolving constant expressions takes into account the value of simple
* and qualified names that refer to constant variables (JLS2 4.12.4).
*
*
* Note 1: enum constants are not considered constant expressions.
* The result is always null for these.
*
*
* Note 2: Compile-time constant expressions cannot denote null.
* So technically {@link NullLiteral} nodes are not constant expressions.
* The result is null for these nonetheless.
*
*
* @return the constant expression value, or null if this
* expression has no constant expression value or if bindings were not
* requested when the AST was created
* @since 3.1
*/
public final Object resolveConstantExpressionValue() {
return this.ast.getBindingResolver().resolveConstantExpressionValue(this);
}
/**
* Resolves and returns the binding for the type of this expression.
*
* Note that bindings are generally unavailable unless requested when the
* AST is being built.
*
*
* @return the binding for the type of this expression, or
* null if the type cannot be resolved
*/
public final ITypeBinding resolveTypeBinding() {
return this.ast.getBindingResolver().resolveExpressionType(this);
}
/**
* Returns whether this expression node is the site of a boxing
* conversion (JLS3 5.1.7). This information is available only
* when bindings are requested when the AST is being built.
*
* @return true if this expression is the site of a
* boxing conversion, or false if either no boxing conversion
* is involved or if bindings were not requested when the AST was created
* @since 3.1
*/
public final boolean resolveBoxing() {
return this.ast.getBindingResolver().resolveBoxing(this);
}
/**
* Returns whether this expression node is the site of an unboxing
* conversion (JLS3 5.1.8). This information is available only
* when bindings are requested when the AST is being built.
*
* @return true if this expression is the site of an
* unboxing conversion, or false if either no unboxing
* conversion is involved or if bindings were not requested when the
* AST was created
* @since 3.1
*/
public final boolean resolveUnboxing() {
return this.ast.getBindingResolver().resolveUnboxing(this);
}
}