/*******************************************************************************
 * Copyright (c) 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;

/**
 * Single member annotation node (added in JLS3 API). The single member annotation 
 * "@foo(bar)" is equivalent to the normal annotation "@foo(value=bar)". 
 * <p>
 * <pre>
 * SingleMemberAnnotation:
 *   <b>@</b> TypeName <b>(</b> Expression  <b>)</b>
 * </pre>
 * Within annotations, only certain kinds of expressions are meaningful,
 * including other annotations.
 * </p>
 * <p>
 * Note: This API element is only needed for dealing with Java code that uses
 * new language features of J2SE 1.5. It is included in anticipation of J2SE
 * 1.5 support, which is planned for the next release of Eclipse after 3.0, and
 * may change slightly before reaching its final form.
 * </p>
 * @since 3.0
 */
public final class SingleMemberAnnotation extends Annotation {
	
	/**
	 * The "typeName" structural property of this node type.
	 * @since 3.0
	 */
	public static final ChildPropertyDescriptor TYPE_NAME_PROPERTY = 
		internalTypeNamePropertyFactory(SingleMemberAnnotation.class);

	/**
	 * The "value" structural property of this node type.
	 * @since 3.0
	 */
	public static final ChildPropertyDescriptor VALUE_PROPERTY = 
		new ChildPropertyDescriptor(SingleMemberAnnotation.class, "value", Expression.class, MANDATORY, CYCLE_RISK); //$NON-NLS-1$

	/**
	 * A list of property descriptors (element type: 
	 * {@link StructuralPropertyDescriptor}),
	 * or null if uninitialized.
	 * @since 3.0
	 */
	private static final List PROPERTY_DESCRIPTORS;
	
	static {
		List propertyList = new ArrayList(3);
		createPropertyList(SingleMemberAnnotation.class, propertyList);
		addProperty(TYPE_NAME_PROPERTY, propertyList);
		addProperty(VALUE_PROPERTY, propertyList);
		PROPERTY_DESCRIPTORS = reapPropertyList(propertyList);
	}
	
	/**
	 * 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 AST.JLS* constants
	 * @return a list of property descriptors (element type: 
	 * {@link StructuralPropertyDescriptor})
	 * @since 3.0
	 */
	public static List propertyDescriptors(int apiLevel) {
		return PROPERTY_DESCRIPTORS;
	}
	
	/**
	 * The value; lazily initialized; defaults to a unspecified, but legal,
	 * expression.
	 */
	private Expression value = null;

	/**
	 * Creates a new unparented normal annotation node owned 
	 * by the given AST.  By default, the annotation has an
	 * unspecified type name and an unspecified value.
	 * <p>
	 * N.B. This constructor is package-private.
	 * </p>
	 * 
	 * @param ast the AST that is to own this node
	 */
	SingleMemberAnnotation(AST ast) {
		super(ast);
	    unsupportedIn2();
	}

	/* (omit javadoc for this method)
	 * Method declared on ASTNode.
	 * @since 3.0
	 */
	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 == TYPE_NAME_PROPERTY) {
			if (get) {
				return getTypeName();
			} else {
				setTypeName((Name) child);
				return null;
			}
		}
		if (property == VALUE_PROPERTY) {
			if (get) {
				return getValue();
			} else {
				setValue((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 BodyDeclaration.
	 */
	final ChildPropertyDescriptor internalTypeNameProperty() {
		return TYPE_NAME_PROPERTY;
	}

	/* (omit javadoc for this method)
	 * Method declared on ASTNode.
	 */
	final int getNodeType0() {
		return SINGLE_MEMBER_ANNOTATION;
	}

	/* (omit javadoc for this method)
	 * Method declared on ASTNode.
	 */
	ASTNode clone0(AST target) {
		SingleMemberAnnotation result = new SingleMemberAnnotation(target);
		result.setSourceRange(this.getStartPosition(), this.getLength());
		result.setTypeName((Name) ASTNode.copySubtree(target, getTypeName()));
		result.setValue((Expression) ASTNode.copySubtree(target, getValue()));
		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, getTypeName());
			acceptChild(visitor, getValue());
		}
		visitor.endVisit(this);
	}
	
	/**
	 * Returns the value of this annotation.
	 * 
	 * @return the value node
	 */ 
	public Expression getValue() {
		if (this.value == null) {
			// lazy init must be thread-safe for readers
			synchronized (this) {
				if (this.value == null) {
					preLazyInit();
					this.value = new SimpleName(this.ast);
					postLazyInit(this.value, VALUE_PROPERTY);
				}
			}
		}
		return this.value;
	}
		
	/**
	 * Sets the value of this annotation.
	 * 
	 * @param value the new value
	 * @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 setValue(Expression value) {
		if (value == null) {
			throw new IllegalArgumentException();
		}
		ASTNode oldChild = this.value;
		preReplaceChild(oldChild, value, VALUE_PROPERTY);
		this.value = value;
		postReplaceChild(oldChild, value, VALUE_PROPERTY);
	}

	/* (omit javadoc for this method)
	 * Method declared on ASTNode.
	 */
	int memSize() {
		return super.memSize() + 1 * 4;
	}
	
	/* (omit javadoc for this method)
	 * Method declared on ASTNode.
	 */
	int treeSize() {
		return
			memSize()
			+ (this.typeName == null ? 0 : getTypeName().treeSize())
			+ (this.value == null ? 0 : getValue().treeSize());
	}
}
