/*******************************************************************************
* Copyright (c) 2000, 2008 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;
import java.util.ArrayList;
import java.util.List;
/**
* Field access expression AST node type.
*
* <pre>
* FieldAccess:
* Expression <b>.</b> Identifier
* </pre>
*
* <p>
* Note that there are several kinds of expressions that resemble field access expressions:
* qualified names, this expressions, and super field access expressions. The following guidelines
* help with correct usage:
* <ul>
* <li>An expression like "foo.this" can only be represented as a this expression (
* <code>ThisExpression</code>) containing a simple name. "this" is a keyword, and therefore invalid
* as an identifier.</li>
* <li>An expression like "this.foo" can only be represented as a field access expression (
* <code>FieldAccess</code>) containing a this expression and a simple name. Again, this is because
* "this" is a keyword, and therefore invalid as an identifier.</li>
* <li>An expression with "super" can only be represented as a super field access expression (
* <code>SuperFieldAccess</code>). "super" is a also keyword, and therefore invalid as an
* identifier.</li>
* <li>An expression like "foo.bar" can be represented either as a qualified name (
* <code>QualifiedName</code>) or as a field access expression (<code>FieldAccess</code>) containing
* simple names. Either is acceptable, and there is no way to choose between them without
* information about what the names resolve to (<code>ASTParser</code> may return either).</li>
* <li>Other expressions ending in an identifier, such as "foo().bar" can only be represented as
* field access expressions (<code>FieldAccess</code>).</li>
* </ul>
* </p>
*
* @see QualifiedName
* @see ThisExpression
* @see SuperFieldAccess
* @since 2.0
* @noinstantiate This class is not intended to be instantiated by clients.
*/
public class FieldAccess extends Expression {
/**
* The "expression" structural property of this node type.
*
* @since 3.0
*/
public static final ChildPropertyDescriptor EXPRESSION_PROPERTY=
new ChildPropertyDescriptor(FieldAccess.class, "expression", Expression.class, MANDATORY, CYCLE_RISK); //$NON-NLS-1$
/**
* The "name" structural property of this node type.
*
* @since 3.0
*/
public static final ChildPropertyDescriptor NAME_PROPERTY=
new ChildPropertyDescriptor(FieldAccess.class, "name", SimpleName.class, MANDATORY, NO_CYCLE_RISK); //$NON-NLS-1$
/**
* A list of property descriptors (element type: {@link StructuralPropertyDescriptor}), or null
* if uninitialized.
*/
private static final List PROPERTY_DESCRIPTORS;
static {
List properyList= new ArrayList(3);
createPropertyList(FieldAccess.class, properyList);
addProperty(EXPRESSION_PROPERTY, properyList);
addProperty(NAME_PROPERTY, properyList);
PROPERTY_DESCRIPTORS= reapPropertyList(properyList);
}
/**
* Returns a list of structural property descriptors for this node type. Clients must not modify
* the result.
*
* @param apiLevel the API level; one of the <code>AST.JLS*</code> constants
*
* @return a list of property descriptors (element type: {@link StructuralPropertyDescriptor})
* @since 3.0
*/
public static List propertyDescriptors(int apiLevel) {
return PROPERTY_DESCRIPTORS;
}
/**
* The expression; lazily initialized; defaults to an unspecified, but legal, simple name.
*/
private Expression expression= null;
/**
* The field; lazily initialized; defaults to an unspecified, but legal, simple field name.
*/
private SimpleName fieldName= null;
/**
* Creates a new unparented node for a field access expression owned by the given AST. By
* default, the expression and field are both unspecified, but legal, names.
* <p>
* N.B. This constructor is package-private.
* </p>
*
* @param ast the AST that is to own this node
*/
FieldAccess(AST ast) {
super(ast);
}
/* (omit javadoc for this method)
* Method declared on ASTNode.
*/
final List internalStructuralPropertiesForType(int apiLevel) {
return propertyDescriptors(apiLevel);
}
/* (omit javadoc for this method)
* Method declared on ASTNode.
*/
final ASTNode internalGetSetChildProperty(ChildPropertyDescriptor property, boolean get, ASTNode child) {
if (property == EXPRESSION_PROPERTY) {
if (get) {
return getExpression();
} else {
setExpression((Expression)child);
return null;
}
}
if (property == NAME_PROPERTY) {
if (get) {
return getName();
} else {
setName((SimpleName)child);
return null;
}
}
// allow default implementation to flag the error
return super.internalGetSetChildProperty(property, get, child);
}
/* (omit javadoc for this method)
* Method declared on ASTNode.
*/
final int getNodeType0() {
return FIELD_ACCESS;
}
/* (omit javadoc for this method)
* Method declared on ASTNode.
*/
ASTNode clone0(AST target) {
FieldAccess result= new FieldAccess(target);
result.setSourceRange(getStartPosition(), getLength());
result.setExpression((Expression)getExpression().clone(target));
result.setName((SimpleName)getName().clone(target));
return result;
}
/* (omit javadoc for this method)
* Method declared on ASTNode.
*/
final boolean subtreeMatch0(ASTMatcher matcher, Object other) {
// dispatch to correct overloaded match method
return matcher.match(this, other);
}
/* (omit javadoc for this method)
* Method declared on ASTNode.
*/
void accept0(ASTVisitor visitor) {
boolean visitChildren= visitor.visit(this);
if (visitChildren) {
// visit children in normal left to right reading order
acceptChild(visitor, getExpression());
acceptChild(visitor, getName());
}
visitor.endVisit(this);
}
/**
* Returns the expression of this field access expression.
*
* @return the expression node
*/
public Expression getExpression() {
if (this.expression == null) {
// lazy init must be thread-safe for readers
synchronized (this) {
if (this.expression == null) {
preLazyInit();
this.expression= new SimpleName(this.ast);
postLazyInit(this.expression, EXPRESSION_PROPERTY);
}
}
}
return this.expression;
}
/**
* Sets the expression of this field access expression.
*
* @param expression the new expression
* @exception IllegalArgumentException if:
* <ul>
* <li>the node belongs to a different AST</li>
* <li>the node already has a parent</li>
* <li>a cycle in would be created</li>
* </ul>
*/
public void setExpression(Expression expression) {
if (expression == null) {
throw new IllegalArgumentException();
}
ASTNode oldChild= this.expression;
preReplaceChild(oldChild, expression, EXPRESSION_PROPERTY);
this.expression= expression;
postReplaceChild(oldChild, expression, EXPRESSION_PROPERTY);
}
/**
* Returns the name of the field accessed in this field access expression.
*
* @return the field name
*/
public SimpleName getName() {
if (this.fieldName == null) {
// lazy init must be thread-safe for readers
synchronized (this) {
if (this.fieldName == null) {
preLazyInit();
this.fieldName= new SimpleName(this.ast);
postLazyInit(this.fieldName, NAME_PROPERTY);
}
}
}
return this.fieldName;
}
/**
* Sets the name of the field accessed in this field access expression.
*
* @param fieldName the field name
* @exception IllegalArgumentException if:
* <ul>
* <li>the node belongs to a different AST</li>
* <li>the node already has a parent</li>
* </ul>
*/
public void setName(SimpleName fieldName) {
if (fieldName == null) {
throw new IllegalArgumentException();
}
ASTNode oldChild= this.fieldName;
preReplaceChild(oldChild, fieldName, NAME_PROPERTY);
this.fieldName= fieldName;
postReplaceChild(oldChild, fieldName, NAME_PROPERTY);
}
/* (omit javadoc for this method)
* Method declared on ASTNode.
*/
int memSize() {
// treat Code as free
return BASE_NODE_SIZE + 2 * 4;
}
/**
* Resolves and returns the binding for the field accessed by this expression.
* <p>
* Note that bindings are generally unavailable unless requested when the AST is being built.
* </p>
*
* @return the variable binding, or <code>null</code> if the binding cannot be resolved
* @since 3.0
*/
public IVariableBinding resolveFieldBinding() {
return this.ast.getBindingResolver().resolveField(this);
}
/* (omit javadoc for this method)
* Method declared on ASTNode.
*/
int treeSize() {
return memSize()
+ (this.expression == null ? 0 : getExpression().treeSize())
+ (this.fieldName == null ? 0 : getName().treeSize());
}
}