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* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
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* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.cayenne.dba.oracle;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import org.apache.cayenne.CayenneRuntimeException;
import org.apache.cayenne.access.DataNode;
import org.apache.cayenne.access.QueryLogger;
import org.apache.cayenne.dba.JdbcAdapter;
import org.apache.cayenne.dba.JdbcPkGenerator;
import org.apache.cayenne.dba.QuotingStrategy;
import org.apache.cayenne.map.DataMap;
import org.apache.cayenne.map.DbEntity;
import org.apache.cayenne.map.DbKeyGenerator;
/**
* Sequence-based primary key generator implementation for Oracle. Uses Oracle sequences
* to generate primary key values. This approach is at least 50% faster when tested with
* Oracle compared to the lookup table approach.
* <p>
* When using Cayenne key caching mechanism, make sure that sequences in the database have
* "INCREMENT BY" greater or equal to OraclePkGenerator "pkCacheSize" property value. If
* this is not the case, you will need to adjust PkGenerator value accordingly. For
* example when sequence is incremented by 1 each time, use the following code:
* </p>
*
* <pre>
* dataNode.getAdapter().getPkGenerator().setPkCacheSize(1);
* </pre>
*/
public class OraclePkGenerator extends JdbcPkGenerator {
protected OraclePkGenerator(JdbcAdapter adapter) {
super(adapter);
}
private static final String _SEQUENCE_PREFIX = "pk_";
@Override
public void createAutoPk(DataNode node, List dbEntities) throws Exception {
List sequences = getExistingSequences(node);
// create needed sequences
Iterator it = dbEntities.iterator();
while (it.hasNext()) {
DbEntity ent = (DbEntity) it.next();
if (!sequences.contains(sequenceName(ent))) {
runUpdate(node, createSequenceString(ent));
}
}
}
@Override
public List createAutoPkStatements(List dbEntities) {
List<String> list = new ArrayList<String>();
Iterator it = dbEntities.iterator();
while (it.hasNext()) {
DbEntity ent = (DbEntity) it.next();
list.add(createSequenceString(ent));
}
return list;
}
@Override
public void dropAutoPk(DataNode node, List dbEntities) throws Exception {
List sequences = getExistingSequences(node);
// drop obsolete sequences
Iterator it = dbEntities.iterator();
while (it.hasNext()) {
DbEntity ent = (DbEntity) it.next();
String name;
if (ent.getDataMap().isQuotingSQLIdentifiers()) {
DbEntity tempEnt = new DbEntity();
DataMap dm = new DataMap();
dm.setQuotingSQLIdentifiers(false);
tempEnt.setDataMap(dm);
tempEnt.setName(ent.getName());
name = stripSchemaName(sequenceName(tempEnt));
}
else {
name = stripSchemaName(sequenceName(ent));
}
if (sequences.contains(name)) {
runUpdate(node, dropSequenceString(ent));
}
}
}
@Override
public List dropAutoPkStatements(List dbEntities) {
List<String> list = new ArrayList<String>();
Iterator it = dbEntities.iterator();
while (it.hasNext()) {
DbEntity ent = (DbEntity) it.next();
list.add(dropSequenceString(ent));
}
return list;
}
protected String createSequenceString(DbEntity ent) {
StringBuilder buf = new StringBuilder();
buf
.append("CREATE SEQUENCE ")
.append(sequenceName(ent))
.append(" START WITH 200")
.append(" INCREMENT BY ")
.append(pkCacheSize(ent));
return buf.toString();
}
/**
* Returns a SQL string needed to drop any database objects associated with automatic
* primary key generation process for a specific DbEntity.
*/
protected String dropSequenceString(DbEntity ent) {
StringBuilder buf = new StringBuilder();
buf.append("DROP SEQUENCE ").append(sequenceName(ent));
return buf.toString();
}
/**
* Generates primary key by calling Oracle sequence corresponding to the
* <code>dbEntity</code>. Executed SQL looks like this:
*
* <pre>
* SELECT pk_table_name.nextval FROM DUAL
* </pre>
*
* @since 3.0
*/
@Override
protected long longPkFromDatabase(DataNode node, DbEntity entity) throws Exception {
DbKeyGenerator pkGenerator = entity.getPrimaryKeyGenerator();
String pkGeneratingSequenceName;
if (pkGenerator != null
&& DbKeyGenerator.ORACLE_TYPE.equals(pkGenerator.getGeneratorType())
&& pkGenerator.getGeneratorName() != null)
pkGeneratingSequenceName = pkGenerator.getGeneratorName();
else
pkGeneratingSequenceName = sequenceName(entity);
Connection con = node.getDataSource().getConnection();
try {
Statement st = con.createStatement();
try {
String sql = "SELECT " + pkGeneratingSequenceName + ".nextval FROM DUAL";
QueryLogger.logQuery(sql, Collections.EMPTY_LIST);
ResultSet rs = st.executeQuery(sql);
try {
// Object pk = null;
if (!rs.next()) {
throw new CayenneRuntimeException(
"Error generating pk for DbEntity " + entity.getName());
}
return rs.getLong(1);
}
finally {
rs.close();
}
}
finally {
st.close();
}
}
finally {
con.close();
}
}
protected int pkCacheSize(DbEntity entity) {
// use custom generator if possible
DbKeyGenerator keyGenerator = entity.getPrimaryKeyGenerator();
if (keyGenerator != null
&& DbKeyGenerator.ORACLE_TYPE.equals(keyGenerator.getGeneratorType())
&& keyGenerator.getGeneratorName() != null) {
Integer size = keyGenerator.getKeyCacheSize();
return (size != null && size.intValue() >= 1) ? size.intValue() : super
.getPkCacheSize();
}
else {
return super.getPkCacheSize();
}
}
/** Returns expected primary key sequence name for a DbEntity. */
protected String sequenceName(DbEntity entity) {
boolean status;
if (entity.getDataMap() != null && entity.getDataMap().isQuotingSQLIdentifiers()) {
status = true;
}
else {
status = false;
}
QuotingStrategy context = getAdapter().getQuotingStrategy(status);
// use custom generator if possible
DbKeyGenerator keyGenerator = entity.getPrimaryKeyGenerator();
if (keyGenerator != null
&& DbKeyGenerator.ORACLE_TYPE.equals(keyGenerator.getGeneratorType())
&& keyGenerator.getGeneratorName() != null) {
return keyGenerator.getGeneratorName().toLowerCase();
}
else {
String entName = entity.getName();
String seqName = _SEQUENCE_PREFIX + entName.toLowerCase();
if (entity.getSchema() != null && entity.getSchema().length() > 0) {
seqName = context.quoteString(entity.getSchema())
+ "."
+ context.quoteString(seqName);
}
else {
seqName = context.quoteString(seqName);
}
return seqName;
}
}
protected String stripSchemaName(String sequenceName) {
int ind = sequenceName.indexOf('.');
return (ind >= 0) ? sequenceName.substring(ind + 1) : sequenceName;
}
/**
* Fetches a list of existing sequences that might match Cayenne generated ones.
*/
protected List getExistingSequences(DataNode node) throws SQLException {
// check existing sequences
Connection con = node.getDataSource().getConnection();
try {
Statement sel = con.createStatement();
try {
String sql = "SELECT LOWER(SEQUENCE_NAME) FROM ALL_SEQUENCES";
QueryLogger.logQuery(sql, Collections.EMPTY_LIST);
ResultSet rs = sel.executeQuery(sql);
try {
List<String> sequenceList = new ArrayList<String>();
while (rs.next()) {
sequenceList.add(rs.getString(1));
}
return sequenceList;
}
finally {
rs.close();
}
}
finally {
sel.close();
}
}
finally {
con.close();
}
}
}