| /* |
| * Copyright (c) 1998, 2020 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.history; |
| |
| import org.eclipse.persistence.expressions.*; |
| import org.eclipse.persistence.internal.expressions.*; |
| import org.eclipse.persistence.internal.helper.*; |
| |
| /** |
| * <b>Purpose:</b>Wraps an immutable value for a past time, represented as a |
| * database system change number. |
| * <p> |
| * This should be specified with an Oracle platform supporting flashback, |
| * and the value will be written to the SQL FROM clause: |
| * <p> |
| * SELECT ... FROM EMPLOYEE AS OF SCN (value) t0, ... |
| * @since OracleAS TopLink 10<i>g</i> (10.0.3) |
| * @author Stephen McRitchie |
| * @see AsOfClause |
| * @see org.eclipse.persistence.platform.database.OraclePlatform#getSystemChangeNumberQuery |
| */ |
| public class AsOfSCNClause extends AsOfClause { |
| public AsOfSCNClause(Number systemChangeNumber) { |
| super(systemChangeNumber); |
| } |
| |
| public AsOfSCNClause(Long systemChangeNumber) { |
| super(systemChangeNumber); |
| } |
| |
| public AsOfSCNClause(long systemChangeNumber) { |
| super(Long.valueOf(systemChangeNumber)); |
| } |
| |
| public AsOfSCNClause(Expression expression) { |
| super(expression); |
| } |
| |
| /** |
| * INTERNAL: |
| * Prints the as of clause for an expression inside of the FROM clause. |
| */ |
| @Override |
| public void printSQL(ExpressionSQLPrinter printer) { |
| printer.printString("AS OF SCN ("); |
| Object value = getValue(); |
| if (value instanceof Expression) { |
| // Sort of an implementation of native sql. |
| // Print AS OF SCN (1000L - 45L) not AS OF ('1000L - 45L'). |
| if ((value instanceof ConstantExpression) && (((ConstantExpression)value).getValue() instanceof String)) { |
| printer.printString((String)((ConstantExpression)value).getValue()); |
| } else { |
| printer.printExpression((Expression)value); |
| } |
| } else { |
| ConversionManager converter = ConversionManager.getDefaultManager(); |
| value = converter.convertObject(value, ClassConstants.LONG); |
| printer.printPrimitive(value); |
| } |
| printer.printString(")"); |
| } |
| |
| /** |
| * PUBLIC: |
| */ |
| @Override |
| public boolean isAsOfSCNClause() { |
| return true; |
| } |
| } |