org.eclipse.persistence.sequencing.NativeSequence 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.sequencing;
import org.eclipse.persistence.queries.*;
import org.eclipse.persistence.internal.databaseaccess.DatabasePlatform;
import org.eclipse.persistence.internal.databaseaccess.DatasourcePlatform;
/**
*
* Purpose: Define a database's native sequencing mechanism.
*
* Description
* Many databases have built in support for sequencing.
* This can be a SEQUENCE object such as in Oracle,
* or a auto-incrementing column such as the IDENTITY field in Sybase.
* For an auto-incrementing column the preallocation size is always 1.
* For a SEQUENCE object the preallocation size must match the SEQUENCE objects "increment by".
*/
public class NativeSequence extends QuerySequence {
/**
* true indicates that identity should be used - if the platform supports identity.
* false indicates that sequence objects should be used - if the platform supports sequence objects.
*/
protected boolean shouldUseIdentityIfPlatformSupports = true;
/**
* Allow sequencing to be delegated to another sequence if native sequencing is not supported.
*/
protected QuerySequence delegateSequence;
public NativeSequence() {
super();
setShouldSkipUpdate(true);
}
public NativeSequence(boolean shouldUseIdentityIfPlatformSupports) {
super();
setShouldSkipUpdate(true);
setShouldUseIdentityIfPlatformSupports(shouldUseIdentityIfPlatformSupports);
}
/**
* Create a new sequence with the name.
*/
public NativeSequence(String name) {
super(name);
setShouldSkipUpdate(true);
}
public NativeSequence(String name, boolean shouldUseIdentityIfPlatformSupports) {
super(name);
setShouldSkipUpdate(true);
setShouldUseIdentityIfPlatformSupports(shouldUseIdentityIfPlatformSupports);
}
/**
* Create a new sequence with the name and sequence pre-allocation size.
*/
public NativeSequence(String name, int size) {
super(name, size);
setShouldSkipUpdate(true);
}
public NativeSequence(String name, int size, boolean shouldUseIdentityIfPlatformSupports) {
super(name, size);
setShouldSkipUpdate(true);
setShouldUseIdentityIfPlatformSupports(shouldUseIdentityIfPlatformSupports);
}
public NativeSequence(String name, int size, int initialValue) {
super(name, size, initialValue);
setShouldSkipUpdate(true);
}
public NativeSequence(String name, int size, int initialValue, boolean shouldUseIdentityIfPlatformSupports) {
super(name, size, initialValue);
setShouldSkipUpdate(true);
setShouldUseIdentityIfPlatformSupports(shouldUseIdentityIfPlatformSupports);
}
public boolean isNative() {
if (this.delegateSequence != null) {
return this.delegateSequence.isNative();
}
return true;
}
public void setShouldUseIdentityIfPlatformSupports(boolean shouldUseIdentityIfPlatformSupports) {
this.shouldUseIdentityIfPlatformSupports = shouldUseIdentityIfPlatformSupports;
}
public boolean shouldUseIdentityIfPlatformSupports() {
return shouldUseIdentityIfPlatformSupports;
}
public boolean equals(Object obj) {
if (obj instanceof NativeSequence) {
return equalNameAndSize(this, (NativeSequence)obj);
} else {
return false;
}
}
@Override
public int hashCode() {
String name = getName();
int result = name != null ? name.hashCode() : 0;
result = 31 * result + getPreallocationSize();
return result;
}
/**
* INTERNAL:
*/
@Override
protected ValueReadQuery buildSelectQuery() {
if (this.delegateSequence != null) {
return this.delegateSequence.buildSelectQuery();
} else if (shouldAcquireValueAfterInsert()) {
return ((DatasourcePlatform)getDatasourcePlatform()).buildSelectQueryForIdentity();
} else {
return ((DatasourcePlatform)getDatasourcePlatform()).buildSelectQueryForSequenceObject();
}
}
/**
* INTERNAL:
*/
@Override
protected ValueReadQuery buildSelectQuery(String seqName, Integer size) {
if (this.delegateSequence != null) {
return this.delegateSequence.buildSelectQuery(seqName, size);
} else if (shouldAcquireValueAfterInsert()) {
return ((DatabasePlatform)getDatasourcePlatform()).buildSelectQueryForIdentity(getQualified(seqName), size);
} else {
return ((DatasourcePlatform)getDatasourcePlatform()).buildSelectQueryForSequenceObject(getQualified(seqName), size);
}
}
/**
* Return if the sequence should be replaced by another sequence implementation.
* This is used when the platform does not support the native sequence type.
*/
public boolean hasDelegateSequence() {
return delegateSequence != null;
}
/**
* Return the sequence delegate.
* This is used when the platform does not support the native sequence type.
*/
public QuerySequence getDelegateSequence() {
return delegateSequence;
}
/**
* Set the sequence delegate.
* This is used when the platform does not support the native sequence type.
*/
public void setDelegateSequence(QuerySequence delegateSequence) {
this.delegateSequence = delegateSequence;
}
/**
* INTERNAL:
*/
@Override
public void onConnect() {
DatasourcePlatform platform = (DatasourcePlatform)getDatasourcePlatform();
// Set shouldAcquireValueAfterInsert flag: identity -> true; sequence objects -> false.
if (platform.supportsIdentity() && shouldUseIdentityIfPlatformSupports()) {
// identity is both supported by platform and desired by the NativeSequence
setShouldAcquireValueAfterInsert(true);
} else if (platform.supportsSequenceObjects() && !shouldUseIdentityIfPlatformSupports()) {
// sequence objects is both supported by platform and desired by the NativeSequence
setShouldAcquireValueAfterInsert(false);
} else {
if (platform.getDefaultNativeSequenceToTable() || !platform.supportsNativeSequenceNumbers()) {
// If native sequencing is not supported, or IDENTITY not desire, use TABLE.
this.delegateSequence = new TableSequence();
this.delegateSequence.setName(getName());
this.delegateSequence.onConnect(platform);
setShouldUseTransaction(this.delegateSequence.shouldUseTransaction());
setShouldAcquireValueAfterInsert(this.delegateSequence.shouldAcquireValueAfterInsert());
setShouldSkipUpdate(this.delegateSequence.shouldSkipUpdate());
setShouldSelectBeforeUpdate(this.delegateSequence.shouldSelectBeforeUpdate());
setUpdateQuery(this.delegateSequence.getUpdateQuery());
super.onConnect();
return;
} else {
// platform support contradicts to NativeSequence setting - go with platform supported choice.
// platform must support either identity or sequence objects (otherwise ValidationException would've been thrown earlier),
// therefore here dbPlatform.supportsIdentity() == !dbPlatform.supportsSequenceObjects().
setShouldAcquireValueAfterInsert(platform.supportsIdentity());
}
}
setShouldUseTransaction(platform.shouldNativeSequenceUseTransaction());
super.onConnect();
}
/**
* INTERNAL:
*/
@Override
public void onDisconnect() {
this.delegateSequence = null;
setShouldAcquireValueAfterInsert(false);
setShouldUseTransaction(false);
super.onDisconnect();
}
}