UnboundExpression.java

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Copyright (c) 2010 Andy Jefferson and others. All rights reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

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Contributors:
    ...
**********************************************************************/
package org.datanucleus.store.rdbms.sql.expression;

import org.datanucleus.store.rdbms.sql.SQLStatement;

/**
 * Representation of an expression for an unbound variable.
 * This is used where we have a variable in use in a query and at the point of needing it we
 * haven't yet bound the variable. For example, in the following query
 * <pre>this.names.contains(var) && var == someValue</pre>
 * in the first clause the "var" is unbound when passing in to the InvokeExpression, so it is passed
 * in as an UnboundExpression, and in that contains() method will be bound to the collection (element)
 * table (a join added).
 */
public class UnboundExpression extends SQLExpression
{
    protected String variableName;

    /**
     * Constructor for an SQL expression for an unbound variable.
     * @param stmt The statement
     * @param variableName name of the variable
     */
    public UnboundExpression(SQLStatement stmt, String variableName)
    {
        super(stmt, null, null);
        this.variableName = variableName;
    }

    /**
     * Accessor for the variable name
     * @return Variable name that this represents
     */
    public String getVariableName()
    {
        return variableName;
    }
}