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/*
 * Copyright (c) 1998, 2018 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:
//     tware - initial API and implementation from for JPA 2.0 criteria API
package org.eclipse.persistence.expressions;

import org.eclipse.persistence.internal.helper.Helper;

/**
 * INTERNAL:
 * A ListExpressionOperator is used with an ArgumentListFunctionExpression.  It is capable
 * of expanding the number of arguments it can be an operator for.  It is built from a set
 * of start strings, a repeating set of separators and a set of termination strings
 *
 * It typically represents a database function that has a variable list of arguments
 *
 * e.g. COALESCE(arg1, arg2, arg3, .... argn)
 *
 * In the example above "COALESCE(" is the start string, "," is the separator and ")" is the
 * end string
 *
 * @see org.eclipse.persistence.internal.expressions.ArgumentListFunctionExpression
 * @see Expression#coalesce()
 * @author tware
 *
 */
public class ListExpressionOperator extends ExpressionOperator {

    protected String[] startStrings = null;
    protected String[] separators = null;
    protected String[] terminationStrings = null;
    protected int numberOfItems = 0;
    protected boolean isComplete = false;

    public void copyTo(ExpressionOperator operator){
        super.copyTo(operator);
        if (operator instanceof ListExpressionOperator){
            ((ListExpressionOperator)operator).startStrings = Helper.copyStringArray(startStrings);
            ((ListExpressionOperator)operator).separators = Helper.copyStringArray(separators);
            ((ListExpressionOperator)operator).terminationStrings = Helper.copyStringArray(terminationStrings);
            // don't copy numberOfItems since this copy method is used to duplicate an operator that
            // may have a different number of items
        }
    }

    /**
     * INTERNAL:
     * Recalculate the database strings each time this is called in
     * case one has been added.
     */
    @Override
    public String[] getDatabaseStrings() {
        databaseStrings = new String[numberOfItems + 1];
        int i = 0;
        while (i < startStrings.length){
            databaseStrings[i] = startStrings[i];
            i++;
        }
        while  (i < numberOfItems - (terminationStrings.length - 1)){
            for (int j=0;j