org.eclipse.persistence.queries.ValueReadQuery Maven / Gradle / Ivy
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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:
// Oracle - initial API and implementation from Oracle TopLink
package org.eclipse.persistence.queries;
/**
* Purpose:
* Concrete class to perform a read of a single data value.
*
*
Responsibilities:
* 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;
}
}