/******************************************************************************* | |
* Copyright (c) 1998, 2013 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 from Oracle TopLink | |
******************************************************************************/ | |
package org.eclipse.persistence.queries; | |
/** | |
* <p><b>Purpose</b>: | |
* Concrete class to perform a read of a single data value. | |
* <p> | |
* <p><b>Responsibilities</b>: | |
* Used in conjunction with CursoredStream size and Platform getSequence. | |
* This can be used to read a single data value (i.e. one field). | |
* A single data value is returned, or null if no rows are returned. | |
* | |
* @author James Sutherland | |
* @since TOPLink/Java 1.2 | |
*/ | |
public class ValueReadQuery extends DirectReadQuery { | |
/** | |
* PUBLIC: | |
* Initialize the state of the query. | |
*/ | |
public ValueReadQuery() { | |
super(); | |
this.resultType = VALUE; | |
} | |
/** | |
* PUBLIC: | |
* Initialize the query to use the specified SQL string. | |
* Warning: Allowing an unverified SQL string to be passed into this | |
* method makes your application vulnerable to SQL injection attacks. | |
*/ | |
public ValueReadQuery(String sqlString) { | |
super(sqlString); | |
this.resultType = VALUE; | |
} | |
/** | |
* PUBLIC: | |
* Initialize the query to use the specified call. | |
*/ | |
public ValueReadQuery(Call call) { | |
super(call); | |
this.resultType = VALUE; | |
} | |
/** | |
* PUBLIC: | |
* Return if this is a value read query. | |
*/ | |
public boolean isValueReadQuery() { | |
return true; | |
} | |
} |