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
/*******************************************************************************
 * 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
 *******************************************************************************/

package org.eclipse.jdt.core.dom;

import java.util.ArrayList;
import java.util.List;

Field access expression AST node type.
FieldAccess:
		Expression . Identifier


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:


  
An expression like "foo.this" can only be represented as a this
  expression (ThisExpression) containing a simple name.
  "this" is a keyword, and therefore invalid as an identifier.
  
An expression like "this.foo" can only be represented as a field
  access expression (FieldAccess) containing a this expression
  and a simple name. Again, this is because "this" is a keyword, and
  therefore invalid as an identifier.
  
An expression with "super" can only be represented as a super field
  access expression (SuperFieldAccess). "super" is a also
  keyword, and therefore invalid as an identifier.
  
An expression like "foo.bar" can be represented either as a
  qualified name (QualifiedName) or as a field access
  expression (FieldAccess) containing simple names. Either
  is acceptable, and there is no way to choose between them without
  information about what the names resolve to
  (ASTParser may return either).
  
Other expressions ending in an identifier, such as "foo().bar" can
  only be represented as field access expressions
  (FieldAccess).

See Also:
QualifiedName
ThisExpression
SuperFieldAccess
Since:
2.0
@noinstantiate
This class is not intended to be instantiated by clients./**
 * 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:
 * </p>
 * <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>
 *
 * @see QualifiedName
 * @see ThisExpression
 * @see SuperFieldAccess
 * @since 2.0
 * @noinstantiate This class is not intended to be instantiated by clients.
 */
@SuppressWarnings("rawtypes")
public class FieldAccess extends Expression {

	
The "expression" structural property of this node type (child type: Expression). 
Since:
3.0/**
	 * The "expression" structural property of this node type (child type: {@link Expression}).
	 * @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 (child type: SimpleName). 
Since:
3.0/**
	 * The "name" structural property of this node type (child type: {@link SimpleName}).
	 * @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: StructuralPropertyDescriptor), or null if uninitialized. /**
	 * 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.
Params:
apiLevel – the API level; one of the
AST.JLS* constants
Returns:
a list of property descriptors (element type: StructuralPropertyDescriptor)
Since:
3.0/**
	 * 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.
/**
	 * 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.
/**
	 * 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.

N.B. This constructor is package-private.

Params:
ast – the AST that is to own this node/**
	 * 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);
	}

	@Override
	final List internalStructuralPropertiesForType(int apiLevel) {
		return propertyDescriptors(apiLevel);
	}

	@Override
	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);
	}

	@Override
	final int getNodeType0() {
		return FIELD_ACCESS;
	}

	@Override
	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;
	}

	@Override
	final boolean subtreeMatch0(ASTMatcher matcher, Object other) {
		// dispatch to correct overloaded match method
		return matcher.match(this, other);
	}

	@Override
	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.
Returns:
the expression node/**
	 * 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.
Params:
expression – the new expression
Throws:
IllegalArgumentException – if:

the node belongs to a different AST
the node already has a parent
a cycle in would be created
/**
	 * 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.
Returns:
the field name/**
	 * 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.
Params:
fieldName – the field name
Throws:
IllegalArgumentException – if:

the node belongs to a different AST
the node already has a parent
/**
	 * 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);
	}

	@Override
	int memSize() {
		// treat Code as free
		return BASE_NODE_SIZE + 2 * 4;
	}

	
Resolves and returns the binding for the field accessed by this
expression.

Note that bindings are generally unavailable unless requested when the
AST is being built.

Returns:
the variable binding, or null if the binding cannot
be resolved
Since:
3.0/**
	 * 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);
	}

	@Override
	int treeSize() {
		return
			memSize()
			+ (this.expression == null ? 0 : getExpression().treeSize())
			+ (this.fieldName == null ? 0 : getName().treeSize());
	}
}