EOGetMapChecker.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.HashSet;
import java.util.List;
import java.util.Set;

import org.geoserver.catalog.Catalog;
import org.geoserver.catalog.LayerInfo;
import org.geoserver.catalog.MetadataMap;
import org.geoserver.platform.ServiceException;
import org.geoserver.wms.GetMapCallback;
import org.geoserver.wms.GetMapCallbackAdapter;
import org.geoserver.wms.GetMapRequest;
import org.geoserver.wms.WMSMapContent;
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.map.RasterLayer;
import org.opengis.parameter.GeneralParameterValue;
import org.opengis.parameter.ParameterDescriptor;
import org.opengis.parameter.ParameterValue;
import org.opengis.referencing.ReferenceIdentifier;

/**
 * This {@link GetMapCallback} is responsible for enforcing that an EO GetMap
 * works as per the spec:
 * 
 * -1- 1 or 3 Bands requested
 * -2- Set the merge behavior for the underlying mosaic
 * 
 * @author Simone Giannecchini, GeoSOlutions SAS
 */
public class EOGetMapChecker extends GetMapCallbackAdapter implements GetMapCallback {
    /** BAND_COVERAGE_VALUE */
    private static final String BAND_COVERAGE_VALUE = EoLayerType.BAND_COVERAGE.name();
    Catalog catalog;
    
    public EOGetMapChecker(Catalog catalog) {
        this.catalog = catalog;
    }
    
    @SuppressWarnings("rawtypes")
    @Override
    public WMSMapContent beforeRender(WMSMapContent content) {
        
        // is this WMS 1.3.0? If not move along
        final GetMapRequest request = content.getRequest();
        if(!"1.3.0".equalsIgnoreCase(request.getVersion())){
            return super.beforeRender(content);
        }
        

        // === look for BANDS layer
        final List<Layer> layers = content.layers();
        RasterLayer layer=null;
        for(Layer tempLayer:layers){
            if(tempLayer instanceof RasterLayer){
                String title = tempLayer.getTitle();
                LayerInfo layerInfo = catalog.getLayerByName(title);        
                if(layerInfo!=null){
                    MetadataMap metadata= layerInfo.getMetadata();
                    if(metadata.containsKey(EoLayerType.KEY)&&metadata.get(EoLayerType.KEY).equals(BAND_COVERAGE_VALUE)){   
                        layer=(RasterLayer) tempLayer;
                        break;
                    }
                }
            }
        }
        if(layer==null){
            // there is no BAND layer, we move on as usual
            return super.beforeRender(content);  
        }
        
        // get the underlying grid reader
        final GridReaderLayer readerLayer=(GridReaderLayer) layer;
        final GeneralParameterValue[] params = readerLayer.getParams();
        
        // get the read parameters for this reader
        try {
            final Set<ParameterDescriptor<List>> dynamicParameters = readerLayer.getReader().getDynamicParameters();
            if(dynamicParameters.isEmpty()){
                throw new IllegalStateException("Layer "+readerLayer.getTitle()+ " has no additional dimensions which are required for an EO BANDS layer");
            }
            final Set<ReferenceIdentifier> dynamicParametersNames= new HashSet<ReferenceIdentifier>();
            for(ParameterDescriptor<List> param:dynamicParameters){
                dynamicParametersNames.add(param.getName());
            }
        
            //looking for the readparams to control dimensions
            // -1- control band stacking
            // -2- check that a valid number of bands has been called
            boolean foundMergeBehavior=false; 
            int foundCustomDimensions=0;
            for(int i=0;i<params.length;i++){
                final ParameterValue param = (ParameterValue) params[i];
                final ParameterDescriptor descriptor = param.getDescriptor();
                final ReferenceIdentifier name = descriptor.getName();
                
                // MERGE_BEHAVIOR
                if (name.equals(ImageMosaicFormat.MERGE_BEHAVIOR.getName())) {
                    foundMergeBehavior=true;
                    param.setValue(MergeBehavior.STACK.toString());
                } else {
                    //Dynamic Parameters checks
                    // -1- only one can have multiple values with cardinality 3
                    if(dynamicParametersNames.contains(name)){
                        final List paramValues=(List) param.getValue();
                        final int size = paramValues.size();
                        if(size!=1&&size!=3){
                            throw new ServiceException(
                                    "Wrong number of values provided to this GetMap for EO BANDS layer. Paremeter:"+name.getCode()+" #:"+size,
                                    "InvalidDimensionValue");
                        }
                        foundCustomDimensions++;
                    }
                 
                }
            }
            // did we find all the custom dimensions
            if(foundCustomDimensions!=dynamicParameters.size()){
                throw new IllegalArgumentException("Not all the dimensions for this EO BANDS layer were requested. Please, check the GetMap request.");
            }
            
            // check if we found and set the merge behavior
            if(!foundMergeBehavior){
                // should not happen
                throw new IllegalStateException("Unable to impose Stacking merge behavior!");
                
            }
            
            // move on as usual
            return super.beforeRender(content);
        } catch(IOException e) {
            throw new ServiceException(e);
        }
    }

}