/*******************************************************************************
 * Copyright (c) 2011, 2014 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation
 *
 ******************************************************************************/
package org.eclipse.persistence.jpa.jpql.tools.model.query;

import org.eclipse.persistence.jpa.jpql.parser.UpdateStatement;

/**
 * The <code><b>UPDATE</b></code> clause of a query consists of a conditional expression used to
 * select objects or values that satisfy the expression. The <code><b>UPDATE</b></code> clause
 * restricts the result of a select statement or the scope of an update operation.
 *
 * <div><b>BNF:</b> <code>update_statement ::= update_clause [where_clause]</code><p></div>
 *
 * @see UpdateStatement
 *
 * @version 2.4
 * @since 2.4
 * @author Pascal Filion
 */
public class UpdateStatementStateObject extends AbstractModifyStatementStateObject {

	/**
	 * Creates a new <code>UpdateStatementStateObject</code>.
	 *
	 * @param parent The parent of this state object, which cannot be <code>null</code>
	 * @exception NullPointerException The given parent cannot be <code>null</code>
	 */
	public UpdateStatementStateObject(JPQLQueryStateObject parent) {
		super(parent);
	}

	/**
	 * {@inheritDoc}
	 */
	public void accept(StateObjectVisitor visitor) {
		visitor.visit(this);
	}

	/**
	 * Adds a new item to the <code><b>UPDATE</b></code> clause.
	 *
	 * @param path The path of the value to update
	 * @return The newly added {@link UpdateItemStateObject}
	 */
	public UpdateItemStateObject addItem(String path) {
		return getModifyClause().addItem(path);
	}

	/**
	 * Adds a new item to the <code><b>UPDATE</b></code> clause.
	 *
	 * @param path The path of the value to update
	 * @param newValue The {@link StateObject} representation of the new value
	 * @return The newly added {@link UpdateItemStateObject}
	 */
	public UpdateItemStateObject addItem(String path, StateObject newValue) {
		return getModifyClause().addItem(path, newValue);
	}

	/**
	 * Adds a new item to the <code><b>UPDATE</b></code> clause.
	 *
	 * @param path The path of the value to update
	 * @param newValue The string representation of the new value to parse and to convert into a
	 * {@link StateObject} representation
	 * @return The newly added {@link UpdateItemStateObject}
	 */
	public UpdateItemStateObject addItem(String path, String newValue) {
		return getModifyClause().addItem(path, newValue);
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	protected AbstractModifyClauseStateObject buildModifyClause() {
		return new UpdateClauseStateObject(this);
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public UpdateStatement getExpression() {
		return (UpdateStatement) super.getExpression();
	}

	/**
	 * Returns the state object representing the <code><b>UPDATE</b></code> clause.
	 *
	 * @return The state object representing the <code><b>UPDATE</b></code> clause, which is never
	 * <code>null</code>
	 */
	@Override
	public UpdateClauseStateObject getModifyClause() {
		return (UpdateClauseStateObject) super.getModifyClause();
	}

	/**
	 * Keeps a reference of the {@link UpdateStatement parsed object} object, which should only be
	 * done when this object is instantiated during the conversion of a parsed JPQL query into
	 * {@link StateObject StateObjects}.
	 *
	 * @param expression The {@link UpdateStatement parsed object} representing an <code><b>UpdateStatement</b></code>
	 * statement
	 */
	public void setExpression(UpdateStatement expression) {
		super.setExpression(expression);
	}
}