Spring factory for Hsqldb URLs

README.md

Spring glue code for HSQLDB

HSQLDB doesn't play that well with Spring when using an in-memory data source. This code provides a HSQLDB URL factory so that a URL can be built from a org.springframework.core.io.Resource, and also shows how the DAO must explicitly invoke the shutdown query.

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd"
       default-lazy-init="true">

    <bean id="hsqldbUrl" class="….HsqldbUrlFactory">
        <property name="database" value="file:${hsqldb_database}" />
    </bean>

    <bean id="hsqldbDataSource"
          class="org.apache.commons.dbcp.BasicDataSource"
          destroy-method="close">
        <property name="driverClassName" value="org.hsqldb.jdbcDriver" />
        <property name="url" ref="hsqldbUrl" />
        <property name="username" value="sa" />
        <property name="password" value="" />

        <property name="validationQuery" value="SELECT count(*) FROM INFORMATION_SCHEMA.SYSTEM_TABLES" />
        <property name="initialSize" value="1" />
        <property name="maxIdle" value="2" />
        <property name="maxActive" value="5" />
    </bean>

    <bean id="conversionDao"
          class="….HsqldbDAOImpl"
          destroy-method="shutdown">
        <property name="dataSource" ref="hsqldbDataSource" />
    </bean>
</beans>

HsqldbDAOImpl.java

import org.springframework.jdbc.core.simple.SimpleJdbcDaoSupport;
import org.springframework.jdbc.core.simple.ParameterizedRowMapper;
import org.springframework.dao.DataIntegrityViolationException;

import java.sql.ResultSet;
import java.sql.SQLException;

import java.util.List;
import java.util.Date;

/**
 * DAO implementation backed by HSQLDB.
 *
 * @author Brian Lalor <[email protected]>
 */
public class HsqldbDAOImpl extends SimpleJdbcDaoSupport
{
    // {{{ shutdown
    /**
     * Performs destroy-time deinitialization of the bean. Required to keep Hsqldb happy.
     */
    public void shutdown() {
        logger.debug("shutting down database");
        getSimpleJdbcTemplate().update("shutdown");
    }
    // }}}
}

HsqldbUrlFactory.java

import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.core.io.Resource;

import java.io.File;

/**
 * Spring factory for Hsqldb URLs.
 *
 * @author Brian Lalor <[email protected]>
 */
public class HsqldbUrlFactory implements InitializingBean, FactoryBean
{
    private Resource databaseRsrc;
    private boolean scriptMustExist = false;
    private String dbFilePath;
    
    // {{{ setDatabase
    public void setDatabase(final Resource database) {
        this.databaseRsrc = database;
    }
    // }}}

    // {{{ setScriptMustExist
    public void setScriptMustExist(final boolean scriptMustExist) {
        this.scriptMustExist = scriptMustExist;
    }
    // }}}
    
    // {{{ afterPropertiesSet
    /** {@inheritDoc} */
    public void afterPropertiesSet() throws Exception {
        dbFilePath = databaseRsrc.getFile().getAbsolutePath();

        if (scriptMustExist) {
            File dbf = new File(dbFilePath + ".script");
            
            if (! dbf.exists()) {
                throw new IllegalArgumentException(dbf.toString() + " does not exist");
            }
        }
    }
    // }}}

    // {{{ getObject
    /** {@inheritDoc} */
    public Object getObject() throws Exception {
        return String.format("jdbc:hsqldb:file:%s;ifexists=true", dbFilePath);
    }
    // }}}
    
    // {{{ getObjectType
    /** {@inheritDoc} */
    public Class getObjectType() {
        return String.class;
    }
    // }}}
    
    // {{{ isSingleton
    /** {@inheritDoc} */
    public boolean isSingleton() {
        return true;
    }
    // }}}
}