EOGetMapCallback.java

/* (c) 2014 Open Source Geospatial Foundation - all rights reserved
 * (c) 2013 OpenPlans
 * This code is licensed under the GPL 2.0 license, available at the root
 * application directory.
 */
package org.geoserver.wms.eo;

import java.io.IOException;
import java.util.List;
import java.util.Set;
import java.util.logging.Logger;

import org.geoserver.catalog.Catalog;
import org.geoserver.catalog.CoverageInfo;
import org.geoserver.platform.ServiceException;
import org.geoserver.wms.GetMapCallback;
import org.geoserver.wms.GetMapCallbackAdapter;
import org.geoserver.wms.WMSMapContent;
import org.geotools.coverage.grid.io.GridCoverage2DReader;
import org.geotools.gce.imagemosaic.ImageMosaicFormat;
import org.geotools.gce.imagemosaic.MergeBehavior;
import org.geotools.map.GridReaderLayer;
import org.geotools.map.Layer;
import org.geotools.util.logging.Logging;
import org.opengis.parameter.GeneralParameterValue;
import org.opengis.parameter.ParameterDescriptor;
import org.opengis.parameter.ParameterValue;
import org.opengis.referencing.ReferenceIdentifier;

/**
 * Convenience base class for writing {@link GetMapCallback} that are only interested in a small
 * subset of the supported events.
 * 
 * @author Andrea Aime - GeoSolutions
 * @author Simone Giannecchini, GeoSolutions
 */
public class EOGetMapCallback extends GetMapCallbackAdapter implements GetMapCallback {
    
    private static final Logger LOGGER = Logging.getLogger(EOGetMapCallback.class);

    private final Catalog catalog;

    public EOGetMapCallback(Catalog catalog) {
        this.catalog = catalog;
    }

    @Override
    public Layer beforeLayer(WMSMapContent content, Layer layer) {
        
        // === check in catalog if it's an EO BAND Layer. If not return untouched
        final CoverageInfo cinfo=catalogChecks(layer);
        if(cinfo==null){
            throw new IllegalStateException("Layer "+layer.getTitle()+" does nto resolve to a coverage");
        }        
        // extract incoming reader
        if(!(layer instanceof GridReaderLayer)){
            throw new IllegalStateException("Layer "+layer.getTitle()+" does nto resolve to a coverage");
        }
        final GridReaderLayer gridReaderLayer = (GridReaderLayer)layer;
        final GridCoverage2DReader reader=gridReaderLayer.getReader();
        
        // === assuming now it is an EO BAND layer we must have either 1 or 3 values for the additional domain
        
        // enforce one dimension
        Set<ParameterDescriptor<List>> dimensions;
        try {
            dimensions = reader.getDynamicParameters();
        
            if (dimensions.size() != 1) {
                throw new IllegalStateException("Coverage " + cinfo.getName()
                        + " has a number of dimensions different than 1");
            }
            // extract curent values and enforce 1 or 3 values
            final GeneralParameterValue[] params = gridReaderLayer.getParams();
            enforceParamCardinality(params,dimensions);
            
            // enforce stacking order
            enforceStackingOrder(params);
        } catch (IOException e) {
            throw new ServiceException(e);
        }
        
        return layer;
    }

    /**
     * @param params
     * @param dimensions
     */
    private void enforceStackingOrder(GeneralParameterValue[] params) {
    
        // look for it
        for(GeneralParameterValue p:params){
            if(p.getDescriptor().getName().equals(ImageMosaicFormat.MERGE_BEHAVIOR.getName())){
                // found it, enfoce cardinality
                ((ParameterValue)p).setValue(MergeBehavior.STACK.name());
                break;
            }
        }
        
    }

    /**
     * @param params
     * @param dimensions
     */
    private void enforceParamCardinality(GeneralParameterValue[] params,
            Set<ParameterDescriptor<List>> dimensions) {
        
        // get parameter name
        final ParameterDescriptor<List> param = dimensions.iterator().next();
        final ReferenceIdentifier paramName=param.getName();
        
        // look for it
        for(GeneralParameterValue p:params){
            if(p.getDescriptor().getName().equals(paramName)){
                // found it, enfoce cardinality
                List value = (List) ((ParameterValue)p).getValue();
                if(value.size()!=1&& value.size()!=3){
                    throw new IllegalStateException();
                }
                break;
            }
        }
        
    }

    /**
     * @param layer
     *
     */
    private CoverageInfo catalogChecks(Layer layer) {
        return catalog.getCoverageByName(layer.getTitle());
    }

}