/*
 * Copyright 2004-2006 H2 Group. Licensed under the H2 License, Version 1.0 (http://h2database.com/html/license.html).
 * Initial Developer: H2 Group
 */
package org.h2.expression;

import org.h2.table.Table;

public class ExpressionVisitor {
    // Is the value independent on unset parameters or on columns of a higher level query, or sequence values (that means can it be evaluated right now)
    public static final int INDEPENDENT = 0;
    
    // Are all aggregates MIN(column), MAX(column), or COUNT(*)?
    public static final int OPTIMIZABLE_MIN_MAX_COUNT_ALL = 1;
    
    // Does the expression return the same results for the same parameters?
    public static final int DETERMINISTIC = 2;
    
    // Can the expression be evaluated, that means are all columns set to 'evaluatable'?
    public static final int EVALUATABLE = 3;
    
    // Request to set the latest modification id
    public static final int SET_MAX_DATA_MODIFICATION_ID = 4;

    int queryLevel;
    public Table table;
    public int type;
    private long maxDataModificationId;
    
    public static ExpressionVisitor get(int type) {
        return new ExpressionVisitor(type);
    }
    
    public long getMaxDataModificationId() {
        return maxDataModificationId;
    }
    
    private ExpressionVisitor(int type) {
        this.type = type;
    }
    
    public void queryLevel(int offset) {
        queryLevel += offset;
    }

    public void addDataModificationId(long v) {
        maxDataModificationId = Math.max(maxDataModificationId, v);
    }

}