/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2006-2008, Open Source Geospatial Foundation (OSGeo)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
*/
package org.geotools.data.sql;
import java.io.IOException;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.logging.Logger;
import org.geotools.data.DataSourceException;
import org.geotools.data.DataStore;
import org.geotools.data.DataStoreFactorySpi;
import org.geotools.data.DataStoreFinder;
/**
* A DataStoreFactory that produces any {@link org.geotools.data.sql.SqlDataStore}, whose
* only purpose is to simplify the process of defining in-process views by
* specifying them as plain SQL SELECT statements in the Map of parameters.
* <p>
* The only mandatory parameter to use this factory is <code>"wrapper.type"</code>, whose
* value must be the fixed literal <code>"sql"</code>. Though a bunch of other parameters
* will be needed to actually find the surrogate datastore, those parameters are
* dependent on the parameters expected by the surrogate datastore factory.
* To prevent parameter name clashes and the surrogate being found prior to this
* factory in the lookup process, all surrogate datastre's parameters must be
* prepended by the literal <code>"surrogate."</code>, as in the following example:
* <pre><code>
* wrapper.type=SQL
* surrogate.property1=...
* surrogate.property2=...
* surrogate.property3=...
* surrogate.property4=...
*
* sqlView.1.typeName = ViewType1
* sqlView.1.sqlQuery = select gid, the_geom, table2.someField \
* from table1, table2 \
* where table1.gid = table2.table1_id
*
* sqlView.2.typeName = ViewType2
* sqlView.2.sqlQuery = select ...
* </code></pre>
* </p>
* <p>
* As noted above, apart from the surrogate parameters you'll have to specify
* which SQL queries to use as FeatureType "views". The process is quite simple:
* prepend <code>"sqlView.N."</code> to <code>"typeName"</code> and <code>"sqlQuery"</code>
* for each view you want to define.
* </p>
*
* @author Gabriel Roldan, Axios Engineering
* @version $id$
* @since 2.3.x
* @source $URL$
*/
public class SqlDataStoreFactory implements DataStoreFactorySpi {
private static final Logger LOGGER = org.geotools.util.logging.Logging.getLogger(SqlDataStore.class.getPackage().getName());
private static final String WRAPPERTYPE_FIXED_VALUE = "sql";
private static Param WRAPPERTYPE = new Param("wrapper.type", String.class,
"Needs to be the fixed value 'sql' to be recognized", true,
WRAPPERTYPE_FIXED_VALUE);
public DataStore createDataStore(Map params) throws IOException {
if(!canProcess(params)){
throw new DataSourceException("can't process " + params);
}
Map surrogateParams = ViewRegisteringFactoryHelper.cleanUpSurrogateParams(params);
DataStore surrogate = DataStoreFinder.getDataStore(surrogateParams);
if(surrogate == null){
throw new DataSourceException("Can't locate surrogate datastore: " +
surrogateParams);
}
if(!(surrogate instanceof SqlDataStore)){
throw new DataSourceException("Surrogate datastore is not a SqlDataStore: " +
surrogate.getClass());
}
SqlDataStore sqlDs = (SqlDataStore)surrogate;
ViewRegisteringFactoryHelper.registerSqlViews(sqlDs, params);
return sqlDs;
}
public DataStore createNewDataStore(Map params) throws IOException {
throw new UnsupportedOperationException();
}
public String getDisplayName() {
return "SQL select based datastore";
}
public String getDescription() {
return "DataStore that adds in-process views to ahother one that implements SqlDataStore";
}
public Param[] getParametersInfo() {
return new Param[]{WRAPPERTYPE};
}
/**
* Checks only if the "wrapper.type" keywords is equal to the
* fixed value "sql".
*/
public boolean canProcess(Map params) {
try {
return WRAPPERTYPE_FIXED_VALUE.equalsIgnoreCase(
String.valueOf( WRAPPERTYPE.lookUp(params) ) );
} catch (Exception e) {
LOGGER.finer("lookup failed on parameter " + WRAPPERTYPE.key);
return false;
}
}
/**
* @return <code>true</code>
* @REVISIT: checking surrogate's datastore availability
* would be costly which goes against this method intentions.
*/
public boolean isAvailable() {
return true;
}
/**
* @return an empty Map. No implementation hints
* defined for this datastore.
*/
public Map getImplementationHints() {
return Collections.EMPTY_MAP;
}
}