/*******************************************************************************
 * 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.List;

/**
 * Labeled statement AST node type.
 *
 * <pre>
 * LabeledStatement:
 *    Identifier <b>:</b> Statement
 * </pre>
 * 
 * @since 2.0
 */
public class LabeledStatement extends Statement {
			
	/**
	 * The "label" structural property of this node type.
	 * @since 3.0
	 */
	public static final ChildPropertyDescriptor LABEL_PROPERTY = 
		new ChildPropertyDescriptor(LabeledStatement.class, "label", SimpleName.class, MANDATORY, NO_CYCLE_RISK); //$NON-NLS-1$

	/**
	 * The "body" structural property of this node type.
	 * @since 3.0
	 */
	public static final ChildPropertyDescriptor BODY_PROPERTY = 
		new ChildPropertyDescriptor(LabeledStatement.class, "body", Statement.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 {
		createPropertyList(LabeledStatement.class);
		addProperty(LABEL_PROPERTY);
		addProperty(BODY_PROPERTY);
		PROPERTY_DESCRIPTORS = reapPropertyList();
	}

	/**
	 * 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 label; lazily initialized; defaults to a unspecified,
	 * legal Java identifier.
	 */
	private SimpleName labelName = null;

	/**
	 * The body statement; lazily initialized; defaults to an unspecified, but 
	 * legal, statement.
	 */
	private Statement body = null;

	/**
	 * Creates a new AST node for a labeled statement owned by the given 
	 * AST. By default, the statement has an unspecified (but legal) label
	 * and an unspecified (but legal) statement.
	 * <p>
	 * N.B. This constructor is package-private.
	 * </p>
	 * 
	 * @param ast the AST that is to own this node
	 */
	LabeledStatement(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 == LABEL_PROPERTY) {
			if (get) {
				return getLabel();
			} else {
				setLabel((SimpleName) child);
				return null;
			}
		}
		if (property == BODY_PROPERTY) {
			if (get) {
				return getBody();
			} else {
				setBody((Statement) 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 LABELED_STATEMENT;
	}

	/* (omit javadoc for this method)
	 * Method declared on ASTNode.
	 */
	ASTNode clone0(AST target) {
		LabeledStatement result = new LabeledStatement(target);
		result.setSourceRange(this.getStartPosition(), this.getLength());
		result.setLabel(
			(SimpleName) ASTNode.copySubtree(target, getLabel()));
		result.setBody(
			(Statement) ASTNode.copySubtree(target, getBody()));
		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, getLabel());
			acceptChild(visitor, getBody());
		}
		visitor.endVisit(this);
	}
	
	/**
	 * Returns the label of this labeled statement.
	 * 
	 * @return the variable name node
	 */ 
	public SimpleName getLabel() {
		if (this.labelName == null) {
			// lazy init must be thread-safe for readers
			synchronized (this) {
				if (this.labelName == null) {
					preLazyInit();
					this.labelName= new SimpleName(this.ast);
					postLazyInit(this.labelName, LABEL_PROPERTY);
				}
			}
		}
		return this.labelName;
	}
		
	/**
	 * Sets the label of this labeled statement.
	 * 
	 * @param label the new label
	 * @exception IllegalArgumentException if:
	 * <ul>
	 * <li>the node belongs to a different AST</li>
	 * <li>the node already has a parent</li>
	 * </ul>
	 */ 
	public void setLabel(SimpleName label) {
		if (label == null) {
			throw new IllegalArgumentException();
		}
		ASTNode oldChild = this.labelName;
		preReplaceChild(oldChild, label, LABEL_PROPERTY);
		this.labelName = label;
		postReplaceChild(oldChild, label, LABEL_PROPERTY);
	}
	
	/**
	 * Returns the body of this labeled statement.
	 * 
	 * @return the body statement node
	 */ 
	public Statement getBody() {
		if (this.body == null) {
			// lazy init must be thread-safe for readers
			synchronized (this) {
				if (this.body == null) {
					preLazyInit();
					this.body= new EmptyStatement(this.ast);
					postLazyInit(this.body, BODY_PROPERTY);
				}
			}
		}
		return this.body;
	}
	
	/**
	 * Sets the body of this labeled statement.
	 * <p>
	 * Special note: The Java language does not allow a local variable declaration
	 * to appear as the body of a labeled statement (they may only appear within a
	 * block). However, the AST will allow a <code>VariableDeclarationStatement</code>
	 * as the body of a <code>LabeledStatement</code>. To get something that will
	 * compile, be sure to embed the <code>VariableDeclarationStatement</code>
	 * inside a <code>Block</code>.
	 * </p>
	 * 
	 * @param statement the body statement 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 setBody(Statement statement) {
		if (statement == null) {
			throw new IllegalArgumentException();
		}
		ASTNode oldChild = this.body;
		preReplaceChild(oldChild, statement, BODY_PROPERTY);
		this.body = statement;
		postReplaceChild(oldChild, statement, BODY_PROPERTY);
	}
	
	/* (omit javadoc for this method)
	 * Method declared on ASTNode.
	 */
	int memSize() {
		return super.memSize() + 2 * 4;
	}
	
	/* (omit javadoc for this method)
	 * Method declared on ASTNode.
	 */
	int treeSize() {
		return
			memSize()
			+ (this.labelName == null ? 0 : getLabel().treeSize())
			+ (this.body == null ? 0 : getBody().treeSize());
	}
}