/*
 * Copyright (c) 2006, 2020 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 v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0,
 * or the Eclipse Distribution License v. 1.0 which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
 */

// Contributors:
//     Oracle - initial API and implementation
//
package org.eclipse.persistence.internal.jpa.jpql;

import org.eclipse.persistence.expressions.Expression;
import org.eclipse.persistence.jpa.jpql.parser.CollectionExpression;
import org.eclipse.persistence.jpa.jpql.parser.UpdateClause;
import org.eclipse.persistence.jpa.jpql.parser.UpdateItem;
import org.eclipse.persistence.jpa.jpql.parser.UpdateStatement;
import org.eclipse.persistence.queries.UpdateAllQuery;

/**
 * This builder is responsible to populate a {@link UpdateAllQuery} representing an <b>UPDATE</b> query.
 *
 * @version 2.4
 * @since 2.3
 * @author Pascal Filion
 * @author John Bracken
 */
final class UpdateQueryVisitor extends AbstractModifyAllQueryBuilder {

    /**
     * Creates a new <code>UpdateQueryBuilder</code>.
     *
     * @param queryContext The context used to query information about the application metadata and
     * cached information
     * @param query The {@link UpdateAllQuery} to populate by using this visitor to visit the parsed
     * tree representation of the JPQL query
     */
    UpdateQueryVisitor(JPQLQueryContext queryContext, UpdateAllQuery query) {
        super(queryContext, query);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void visit(CollectionExpression expression) {
        expression.acceptChildren(this);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void visit(UpdateClause expression) {
        expression.getRangeVariableDeclaration().accept(this);
        expression.getUpdateItems().accept(this);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void visit(UpdateItem expression) {

        // Create the Expression for the state field path expression
        Expression leftExpression = queryContext.buildExpression(expression.getStateFieldPathExpression());

        // Create the Expression for the new value
        Expression rightExpression = queryContext.buildExpression(expression.getNewValue());

        // Add the expressions to the query
        ((UpdateAllQuery) query).addUpdate(leftExpression, rightExpression);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void visit(UpdateStatement expression) {

        expression.getUpdateClause().accept(this);

        if (expression.hasWhereClause()) {
            expression.getWhereClause().accept(this);
        }
    }
}