You have eclipse workspace as it shown in Geoserver Developers Quick Start.
Create new java project. Create new class:
package org.geoserver.wms.cluster;
import org.geoserver.wms.GetMapCallback;
import org.geoserver.wms.GetMapCallbackAdapter;
import org.geoserver.wms.GetMapRequest;
import org.geoserver.wms.WMSMapContent;
public class ClusterGetMapCallbackAdapter extends GetMapCallbackAdapter
implements GetMapCallback {
public ClusterGetMapCallbackAdapter() {
}
@Override
public GetMapRequest initRequest(GetMapRequest request) {
return request;
}
@Override
public void initMapContent(WMSMapContent mapContent) {
}
@Override
public WMSMapContent beforeRender(WMSMapContent mapContent) {
return mapContent;
}
}
Add file applicationContext.xml to META-INF directory:
<?xml version="1.0" encoding="UTF-8"?>
<beans>
<bean id="getMapCallback" class="org.geoserver.wms.cluster.ClusterGetMapCallbackAdapter">
</bean>
</beans>
Append new project to the dependencies of "gs-wms" project.
Build solution. Set breakpoints at your code. Start geoserver. Create WMS layer. Browse to GetMap request. See breakpoints hitting.