/*******************************************************************************
 * Copyright (c) 2006 Oracle. 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:
 *     Oracle - initial API and implementation
 ******************************************************************************/
package org.eclipse.jpt.core.internal.jdtutility;

import org.eclipse.jdt.core.dom.AST;
import org.eclipse.jdt.core.dom.ASTNode;
import org.eclipse.jdt.core.dom.Expression;
import org.eclipse.jdt.core.dom.Name;
import org.eclipse.jdt.core.dom.SimpleType;
import org.eclipse.jdt.core.dom.TypeLiteral;

/**
 * Convert an expression to/from a string representation of a simple type
 * (e.g. "java.lang.Object").
 */
public final class SimpleTypeStringExpressionConverter extends AbstractExpressionConverter {
	private static ExpressionConverter INSTANCE;

	/**
	 * Return the singleton.
	 */
	public static ExpressionConverter instance() {
		if (INSTANCE == null) {
			INSTANCE = new SimpleTypeStringExpressionConverter();
		}
		return INSTANCE;
	}

	/**
	 * Ensure non-instantiability.
	 */
	private SimpleTypeStringExpressionConverter() {
		super();
	}

	@Override
	protected Expression convert_(Object o, AST ast) {
		Name name = ast.newName((String) o);
		org.eclipse.jdt.core.dom.Type type = ast.newSimpleType(name);
		TypeLiteral typeLiteral = ast.newTypeLiteral();
		typeLiteral.setType(type);
		return typeLiteral;
	}

	@Override
	protected Object convert_(Expression expression) {
		if (expression.getNodeType() == ASTNode.TYPE_LITERAL) {
			org.eclipse.jdt.core.dom.Type type = ((TypeLiteral) expression).getType();
			if (type.getNodeType() == ASTNode.SIMPLE_TYPE) {
				return ((SimpleType) type).getName().getFullyQualifiedName();
			}
		}
		return null;
	}

}