/*******************************************************************************
* Copyright (c) 2000, 2010 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.HashMap;
import java.util.List;
import java.util.Map;
/**
* Assignment expression AST node type.
*
* <pre>
* Assignment:
* Expression AssignmentOperator Expression
* </pre>
*
* @since 2.0
* @noinstantiate This class is not intended to be instantiated by clients.
*/
public class Assignment extends Expression {
/**
* Assignment operators (typesafe enumeration).
* <pre>
* AssignmentOperator:<code>
* <b>=</b> ASSIGN
* <b>+=</b> PLUS_ASSIGN
* <b>-=</b> MINUS_ASSIGN
* <b>*=</b> TIMES_ASSIGN
* <b>/=</b> DIVIDE_ASSIGN
* <b>&=</b> BIT_AND_ASSIGN
* <b>|=</b> BIT_OR_ASSIGN
* <b>^=</b> BIT_XOR_ASSIGN
* <b>%=</b> REMAINDER_ASSIGN
* <b><<=</b> LEFT_SHIFT_ASSIGN
* <b>>>=</b> RIGHT_SHIFT_SIGNED_ASSIGN
* <b>>>>=</b> RIGHT_SHIFT_UNSIGNED_ASSIGN</code>
* </pre>
*/
public static class Operator {
/**
* The name of the operator
*/
private String op;
/**
* Creates a new assignment operator with the given name.
* <p>
* Note: this constructor is private. The only instances
* ever created are the ones for the standard operators.
* </p>
*
* @param op the character sequence for the operator
*/
private Operator(String op) {
this.op = op;
}
/**
* Returns the character sequence for the operator.
*
* @return the character sequence for the operator
*/
public String toString() {
return this.op;
}
/** = operator. */
public static final Operator ASSIGN = new Operator("=");//$NON-NLS-1$
/** += operator. */
public static final Operator PLUS_ASSIGN = new Operator("+=");//$NON-NLS-1$
/** -= operator. */
public static final Operator MINUS_ASSIGN = new Operator("-=");//$NON-NLS-1$
/** *= operator. */
public static final Operator TIMES_ASSIGN = new Operator("*=");//$NON-NLS-1$
/** /= operator. */
public static final Operator DIVIDE_ASSIGN = new Operator("/=");//$NON-NLS-1$
/** &= operator. */
public static final Operator BIT_AND_ASSIGN = new Operator("&=");//$NON-NLS-1$
/** |= operator. */
public static final Operator BIT_OR_ASSIGN = new Operator("|=");//$NON-NLS-1$
/** ^= operator. */
public static final Operator BIT_XOR_ASSIGN = new Operator("^=");//$NON-NLS-1$
/** %= operator. */
public static final Operator REMAINDER_ASSIGN = new Operator("%=");//$NON-NLS-1$
/** <<== operator. */
public static final Operator LEFT_SHIFT_ASSIGN =
new Operator("<<=");//$NON-NLS-1$
/** >>= operator. */
public static final Operator RIGHT_SHIFT_SIGNED_ASSIGN =
new Operator(">>=");//$NON-NLS-1$
/** >>>= operator. */
public static final Operator RIGHT_SHIFT_UNSIGNED_ASSIGN =
new Operator(">>>=");//$NON-NLS-1$
/**
* Returns the assignment operator corresponding to the given string,
* or <code>null</code> if none.
* <p>
* <code>toOperator</code> is the converse of <code>toString</code>:
* that is, <code>Operator.toOperator(op.toString()) == op</code> for all
* operators <code>op</code>.
* </p>
*
* @param token the character sequence for the operator
* @return the assignment operator, or <code>null</code> if none
*/
public static Operator toOperator(String token) {
return (Operator) CODES.get(token);
}
/**
* Map from token to operator (key type: <code>String</code>;
* value type: <code>Operator</code>).
*/
private static final Map CODES;
static {
CODES = new HashMap(20);
Operator[] ops = {
ASSIGN,
PLUS_ASSIGN,
MINUS_ASSIGN,
TIMES_ASSIGN,
DIVIDE_ASSIGN,
BIT_AND_ASSIGN,
BIT_OR_ASSIGN,
BIT_XOR_ASSIGN,
REMAINDER_ASSIGN,
LEFT_SHIFT_ASSIGN,
RIGHT_SHIFT_SIGNED_ASSIGN,
RIGHT_SHIFT_UNSIGNED_ASSIGN
};
for (int i = 0; i < ops.length; i++) {
CODES.put(ops[i].toString(), ops[i]);
}
}
}
/**
* The "leftHandSide" structural property of this node type (child type: {@link Expression}).
* @since 3.0
*/
public static final ChildPropertyDescriptor LEFT_HAND_SIDE_PROPERTY =
new ChildPropertyDescriptor(Assignment.class, "leftHandSide", Expression.class, MANDATORY, CYCLE_RISK); //$NON-NLS-1$
/**
* The "operator" structural property of this node type (type: {@link Assignment.Operator}).
* @since 3.0
*/
public static final SimplePropertyDescriptor OPERATOR_PROPERTY =
new SimplePropertyDescriptor(Assignment.class, "operator", Assignment.Operator.class, MANDATORY); //$NON-NLS-1$
/**
* The "rightHandSide" structural property of this node type (child type: {@link Expression}).
* @since 3.0
*/
public static final ChildPropertyDescriptor RIGHT_HAND_SIDE_PROPERTY =
new ChildPropertyDescriptor(Assignment.class, "rightHandSide", Expression.class, MANDATORY, 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(4);
createPropertyList(Assignment.class, properyList);
addProperty(LEFT_HAND_SIDE_PROPERTY, properyList);
addProperty(OPERATOR_PROPERTY, properyList);
addProperty(RIGHT_HAND_SIDE_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 assignment operator; defaults to Assignment.Operator.ASSIGN
*/
private Assignment.Operator assignmentOperator = Assignment.Operator.ASSIGN;
/**
* The left hand side; lazily initialized; defaults to an unspecified,
* but legal, simple name.
*/
private Expression leftHandSide = null;
/**
* The right hand side; lazily initialized; defaults to an unspecified,
* but legal, simple name.
*/
private Expression rightHandSide = null;
/**
* Creates a new AST node for an assignment expression owned by the given
* AST. By default, the node has an assignment operator, and unspecified
* left and right hand sides.
*
* @param ast the AST that is to own this node
*/
Assignment(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 Object internalGetSetObjectProperty(SimplePropertyDescriptor property, boolean get, Object value) {
if (property == OPERATOR_PROPERTY) {
if (get) {
return getOperator();
} else {
setOperator((Operator) value);
return null;
}
}
// allow default implementation to flag the error
return super.internalGetSetObjectProperty(property, get, value);
}
/* (omit javadoc for this method)
* Method declared on ASTNode.
*/
final ASTNode internalGetSetChildProperty(ChildPropertyDescriptor property, boolean get, ASTNode child) {
if (property == LEFT_HAND_SIDE_PROPERTY) {
if (get) {
return getLeftHandSide();
} else {
setLeftHandSide((Expression) child);
return null;
}
}
if (property == RIGHT_HAND_SIDE_PROPERTY) {
if (get) {
return getRightHandSide();
} else {
setRightHandSide((Expression) 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 ASSIGNMENT;
}
/* (omit javadoc for this method)
* Method declared on ASTNode.
*/
ASTNode clone0(AST target) {
Assignment result = new Assignment(target);
result.setSourceRange(getStartPosition(), getLength());
result.setOperator(getOperator());
result.setLeftHandSide((Expression) getLeftHandSide().clone(target));
result.setRightHandSide((Expression) getRightHandSide().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, getLeftHandSide());
acceptChild(visitor, getRightHandSide());
}
visitor.endVisit(this);
}
/**
* Returns the operator of this assignment expression.
*
* @return the assignment operator
*/
public Assignment.Operator getOperator() {
return this.assignmentOperator;
}
/**
* Sets the operator of this assignment expression.
*
* @param assignmentOperator the assignment operator
* @exception IllegalArgumentException if the argument is incorrect
*/
public void setOperator(Assignment.Operator assignmentOperator) {
if (assignmentOperator == null) {
throw new IllegalArgumentException();
}
preValueChange(OPERATOR_PROPERTY);
this.assignmentOperator = assignmentOperator;
postValueChange(OPERATOR_PROPERTY);
}
/**
* Returns the left hand side of this assignment expression.
*
* @return the left hand side node
*/
public Expression getLeftHandSide() {
if (this.leftHandSide == null) {
// lazy init must be thread-safe for readers
synchronized (this) {
if (this.leftHandSide == null) {
preLazyInit();
this.leftHandSide= new SimpleName(this.ast);
postLazyInit(this.leftHandSide, LEFT_HAND_SIDE_PROPERTY);
}
}
}
return this.leftHandSide;
}
/**
* Sets the left hand side of this assignment expression.
*
* @param expression the left hand side node
* @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 setLeftHandSide(Expression expression) {
if (expression == null) {
throw new IllegalArgumentException();
}
// an Assignment may occur inside a Expression - must check cycles
ASTNode oldChild = this.leftHandSide;
preReplaceChild(oldChild, expression, LEFT_HAND_SIDE_PROPERTY);
this.leftHandSide = expression;
postReplaceChild(oldChild, expression, LEFT_HAND_SIDE_PROPERTY);
}
/**
* Returns the right hand side of this assignment expression.
*
* @return the right hand side node
*/
public Expression getRightHandSide() {
if (this.rightHandSide == null) {
// lazy init must be thread-safe for readers
synchronized (this) {
if (this.rightHandSide == null) {
preLazyInit();
this.rightHandSide= new SimpleName(this.ast);
postLazyInit(this.rightHandSide, RIGHT_HAND_SIDE_PROPERTY);
}
}
}
return this.rightHandSide;
}
/**
* Sets the right hand side of this assignment expression.
*
* @param expression the right hand side node
* @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 setRightHandSide(Expression expression) {
if (expression == null) {
throw new IllegalArgumentException();
}
// an Assignment may occur inside a Expression - must check cycles
ASTNode oldChild = this.rightHandSide;
preReplaceChild(oldChild, expression, RIGHT_HAND_SIDE_PROPERTY);
this.rightHandSide = expression;
postReplaceChild(oldChild, expression, RIGHT_HAND_SIDE_PROPERTY);
}
/* (omit javadoc for this method)
* Method declared on ASTNode.
*/
int memSize() {
// treat Code as free
return BASE_NODE_SIZE + 3 * 4;
}
/* (omit javadoc for this method)
* Method declared on ASTNode.
*/
int treeSize() {
return
memSize()
+ (this.leftHandSide == null ? 0 : getLeftHandSide().treeSize())
+ (this.rightHandSide == null ? 0 : getRightHandSide().treeSize());
}
}