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* to you under the Apache License, Version 2.0 (the
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package org.apache.cayenne.dba.oracle;
import org.apache.cayenne.CayenneRuntimeException;
import org.apache.cayenne.access.DataNode;
import org.apache.cayenne.dba.JdbcAdapter;
import org.apache.cayenne.dba.JdbcPkGenerator;
import org.apache.cayenne.map.DataMap;
import org.apache.cayenne.map.DbEntity;
import org.apache.cayenne.map.DbKeyGenerator;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
/**
* 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<DbEntity> dbEntities) throws Exception {
List<String> sequences = getExistingSequences(node);
// create needed sequences
for (DbEntity dbEntity : dbEntities) {
if (!sequences.contains(sequenceName(dbEntity))) {
runUpdate(node, createSequenceString(dbEntity));
}
}
}
/**
* Creates a list of CREATE SEQUENCE statements for the list of DbEntities.
*/
@Override
public List<String> createAutoPkStatements(List<DbEntity> dbEntities) {
List<String> list = new ArrayList<>(dbEntities.size());
for (DbEntity dbEntity : dbEntities) {
list.add(createSequenceString(dbEntity));
}
return list;
}
/**
* Drops PK sequences for all specified DbEntities.
*/
@Override
public void dropAutoPk(DataNode node, List<DbEntity> dbEntities) throws Exception {
List<String> sequences = getExistingSequences(node);
// drop obsolete sequences
for (DbEntity dbEntity : dbEntities) {
String name;
if (dbEntity.getDataMap().isQuotingSQLIdentifiers()) {
DbEntity tempEnt = new DbEntity();
DataMap dm = new DataMap();
dm.setQuotingSQLIdentifiers(false);
tempEnt.setDataMap(dm);
tempEnt.setName(dbEntity.getName());
name = stripSchemaName(sequenceName(tempEnt));
} else {
name = stripSchemaName(sequenceName(dbEntity));
}
if (sequences.contains(name)) {
runUpdate(node, dropSequenceString(dbEntity));
}
}
}
/**
* Creates a list of DROP SEQUENCE statements for the list of DbEntities.
*/
@Override
public List<String> dropAutoPkStatements(List<DbEntity> dbEntities) {
List<String> list = new ArrayList<>(dbEntities.size());
for (DbEntity dbEntity : dbEntities) {
list.add(dropSequenceString(dbEntity));
}
return list;
}
protected String createSequenceString(DbEntity ent) {
return "CREATE SEQUENCE " + sequenceName(ent) + " START WITH " + pkStartValue + " INCREMENT BY " + pkCacheSize(ent);
}
/**
* 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) {
return "DROP SEQUENCE " + sequenceName(ent);
}
protected String selectNextValQuery(String pkGeneratingSequenceName) {
return "SELECT " + pkGeneratingSequenceName + ".nextval FROM DUAL";
}
protected String selectAllSequencesQuery() {
return "SELECT LOWER(SEQUENCE_NAME) FROM ALL_SEQUENCES";
}
/**
* 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);
}
try (Connection con = node.getDataSource().getConnection()) {
try (Statement st = con.createStatement()) {
String sql = selectNextValQuery(pkGeneratingSequenceName);
adapter.getJdbcEventLogger().log(sql);
try (ResultSet rs = st.executeQuery(sql)) {
if (!rs.next()) {
throw new CayenneRuntimeException("Error generating pk for DbEntity %s", entity.getName());
}
return rs.getLong(1);
}
}
}
}
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 >= 1) ? size : super.getPkCacheSize();
} else {
return super.getPkCacheSize();
}
}
/**
* Returns expected primary key sequence name for a DbEntity.
*/
protected String sequenceName(DbEntity entity) {
// 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 seqName = getSequencePrefix() + entity.getName().toLowerCase();
return adapter.getQuotingStrategy().quotedIdentifier(entity, entity.getCatalog(), entity.getSchema(), seqName);
}
}
protected String getSequencePrefix() {
return _SEQUENCE_PREFIX;
}
private 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<String> getExistingSequences(DataNode node) throws SQLException {
// check existing sequences
try (Connection con = node.getDataSource().getConnection()) {
try (Statement sel = con.createStatement()) {
String sql = selectAllSequencesQuery();
adapter.getJdbcEventLogger().log(sql);
try (ResultSet rs = sel.executeQuery(sql)) {
List<String> sequenceList = new ArrayList<>();
while (rs.next()) {
String name = rs.getString(1);
if (name != null) {
sequenceList.add(name.trim());
}
}
return sequenceList;
}
}
}
}
}