com.jn.sqlhelper.dialect.internal.DerbyDialect Maven / Gradle / Ivy
/*
* Copyright 2019 the original author or authors.
*
* Licensed under the LGPL, Version 3.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at http://www.gnu.org/licenses/lgpl-3.0.html
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.jn.sqlhelper.dialect.internal;
import com.jn.langx.util.ClassLoaders;
import com.jn.sqlhelper.common.sql.sqlscript.PlainSqlScriptParser;
import com.jn.sqlhelper.common.sql.sqlscript.PlainSqlStatementBuilder;
import com.jn.sqlhelper.dialect.internal.limit.OffsetFetchFirstOnlyLimitHandler;
/**
* http://db.apache.org/derby/docs/10.14/ref/index.html
*/
public class DerbyDialect extends AbstractDialect {
private int driverVersionMajor;
private int driverVersionMinor;
public DerbyDialect() {
super();
determineDriverVersion();
setLimitHandler(new OffsetFetchFirstOnlyLimitHandler());
setPlainSqlScriptParser(new DerbySqlScriptParser());
}
private void determineDriverVersion() {
try {
ClassLoaders.loadClass("org.apache.derby.tools.sysinfo", DerbyDialect.class.getClassLoader());
} catch (Exception e) {
this.driverVersionMajor = -1;
this.driverVersionMinor = -1;
}
}
private boolean isTenPointFiveReleaseOrNewer() {
return (this.driverVersionMajor > 10) || ((this.driverVersionMajor == 10) && (this.driverVersionMinor >= 5));
}
@Override
public boolean isSupportsLimit() {
return isTenPointFiveReleaseOrNewer();
}
@Override
public boolean isSupportsLimitOffset() {
return isTenPointFiveReleaseOrNewer();
}
@Override
public boolean isSupportsVariableLimit() {
return false;
}
private static class DerbySqlScriptParser extends PlainSqlScriptParser{
@Override
protected PlainSqlStatementBuilder newSqlStatementBuilder() {
return new DerbySqlStatementBuilder();
}
}
/**
* supporting Derby-specific delimiter changes.
*/
private static class DerbySqlStatementBuilder extends PlainSqlStatementBuilder {
@Override
protected String extractAlternateOpenQuote(String token) {
if (token.startsWith("$$")) {
return "$$";
}
return null;
}
}
}