/*******************************************************************************
 * Copyright (c) 2000, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.jdt.core.dom;

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

/**
 * Cast expression AST node type.
 *
 * <pre>
 * CastExpression:
 *    <b>(</b> Type <b>)</b> Expression 
 * </pre>
 * 
 * @since 2.0
 */
public class CastExpression extends Expression {

	/**
	 * The "type" structural property of this node type.
	 * @since 3.0
	 */
	public static final ChildPropertyDescriptor TYPE_PROPERTY = 
		new ChildPropertyDescriptor(CastExpression.class, "type", Type.class, MANDATORY, NO_CYCLE_RISK); //$NON-NLS-1$

	/**
	 * The "expression" structural property of this node type.
	 * @since 3.0
	 */
	public static final ChildPropertyDescriptor EXPRESSION_PROPERTY = 
		new ChildPropertyDescriptor(CastExpression.class, "expression", 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(3);
		createPropertyList(CastExpression.class, properyList);
		addProperty(TYPE_PROPERTY, properyList);
		addProperty(EXPRESSION_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&ast;</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 type; lazily initialized; defaults to a unspecified,
	 * legal type.
	 */
	private Type type = null;

	/**
	 * The expression; lazily initialized; defaults to a unspecified, but legal,
	 * expression.
	 */
	private Expression expression = null;

	/**
	 * Creates a new AST node for a cast expression owned by the given 
	 * AST. By default, the type and expression are unspecified (but legal).
	 * <p>
	 * N.B. This constructor is package-private.
	 * </p>
	 * 
	 * @param ast the AST that is to own this node
	 */
	CastExpression(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 == TYPE_PROPERTY) {
			if (get) {
				return getType();
			} else {
				setType((Type) 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 CAST_EXPRESSION;
	}

	/* (omit javadoc for this method)
	 * Method declared on ASTNode.
	 */
	ASTNode clone0(AST target) {
		CastExpression result = new CastExpression(target);
		result.setSourceRange(this.getStartPosition(), this.getLength());
		result.setType((Type) getType().clone(target));
		result.setExpression((Expression) getExpression().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, getType());
			acceptChild(visitor, getExpression());
		}
		visitor.endVisit(this);
	}
	
	/**
	 * Returns the type in this cast expression.
	 * 
	 * @return the type
	 */ 
	public Type getType() {
		if (this.type == null) {
			// lazy init must be thread-safe for readers
			synchronized (this) {
				if (this.type == null) {
					preLazyInit();
					this.type = this.ast.newPrimitiveType(PrimitiveType.INT);
					postLazyInit(this.type, TYPE_PROPERTY);
				}
			}
		}
		return this.type;
	}

	/**
	 * Sets the type in this cast expression to the given type.
	 * 
	 * @param type the new type
	 * @exception IllegalArgumentException if:
	 * <ul>
	 * <li>the node belongs to a different AST</li>
	 * <li>the node already has a parent</li>
	 * </ul>
	 */ 
	public void setType(Type type) {
		if (type == null) {
			throw new IllegalArgumentException();
		}
		ASTNode oldChild = this.type;
		preReplaceChild(oldChild, type, TYPE_PROPERTY);
		this.type = type;
		postReplaceChild(oldChild, type, TYPE_PROPERTY);
	}
	
	/**
	 * Returns the expression of this cast 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 cast expression.
	 * 
	 * @param expression the new expression 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 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);
	}

	/* (omit javadoc for this method)
	 * Method declared on ASTNode.
	 */
	int memSize() {
		// treat Code as free
		return BASE_NODE_SIZE + 2 * 4;
	}
	
	/* (omit javadoc for this method)
	 * Method declared on ASTNode.
	 */
	int treeSize() {
		return 
			memSize()
			+ (this.expression == null ? 0 : getExpression().treeSize())
			+ (this.type == null ? 0 : getType().treeSize());
	}
}