webcontextmaptemplate.java

esri的ArcGIS Server超级学习模板程序（for java）

package com.esri.solutions.jitk.common.templates.map;

import java.awt.image.RenderedImage;
import java.awt.image.renderable.ParameterBlock;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.text.MessageFormat;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Map.Entry;

import javax.media.jai.JAI;

import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;

import com.esri.adf.web.ags.data.AGSLocalMapResource;
import com.esri.adf.web.ags.data.AGSMapResource;
import com.esri.adf.web.aims.data.AIMSMapResource;
import com.esri.adf.web.data.GISResource;
import com.esri.adf.web.data.WebContext;
import com.esri.adf.web.data.WebContextInitialize;
import com.esri.adf.web.data.WebMap;
import com.esri.adf.web.data.geometry.WebExtent;
import com.esri.adf.web.wms.data.WMSMapResource;
import com.esri.solutions.jitk.common.export.image.WebMapImageExporter;
import com.esri.solutions.jitk.web.data.IGISResourceFactory;
import com.esri.solutions.jitk.web.wcs.data.WCSMapResource;
import com.esri.solutions.jitk.web.wfs.data.WFSMapResource;
import com.sun.media.jai.codec.SeekableStream;

/**
 * Implementation of a Map Template that uses the resources
 * within a {@link WebContext} to define the Map Template.  
 */
public class WebContextMapTemplate extends BaseMapTemplate implements IMapTemplate, WebContextInitialize {

	private static final String INFO_CACHING_PREVIEW = "Caching Preview for Map Template [{0}, {1}]";
	private static final String INFO_GENERATING_PREVIEW = "Generating Preview for Map Template [{0}, {1}]";
	private static final String INFO_USING_CACHED_PREVIEW = "Using Cached Preview for Map Template [{0}, {1}]";
	private static final String WARN_UNABLE_TO_GEN_PREVIEW = "Unable to generate Preview for Map Template [{0},{1}]";
	private static final String ERROR_NULL_WEB_MAP = "WebMap object is required to be within WebContext, but is null.";
	private static final String ERROR_NULL_WEB_CTX = "WebContext object is required, and cannot be null.";
	
	private static final Logger LOG = LogManager.getLogger(WebContextMapTemplate.class);
	
	/**
	 * Reference to WebContext that contains the resources
	 * for the Map Template.
	 */
	private WebContext m_templateCtx;
	
	/**
	 * Reference to Web Map Image Exporter to export the web map to a byte[].
	 */
	private WebMapImageExporter m_mapExporter;

	/**
	 * Indicates if the Preview Image should be cached internally. Optional, <code>false</code>
	 * by default.
	 */
	private boolean m_cachePreview = true;
	
	/**
	 * Cached Preview image if Caching is turned on.
	 */
	private RenderedImage m_preview;
	
	/**
	 * Indicates if the template has been initialized within
	 * the current Web Context.
	 */
	private boolean m_initialized = false;
	
	/**
	 * The Web Context that this template is currently loaded into.
	 */
	private WebContext m_currentCtx;
	
	/**
	 * Contains references to a set of GIS Resource Factories so that
	 * new GIS Resources can be created from the GIS Resources already
	 * within the internal WebContext.
	 */
	private Map<String, IGISResourceFactory<GISResource>> m_factories;
	
	/*
	 * (non-Javadoc)
	 * @see com.esri.solutions.jitk.common.templates.map.IMapTemplate#getPreview()
	 */
	public RenderedImage getPreview() {
		if (m_templateCtx == null) {
			LOG.error(ERROR_NULL_WEB_CTX);
			throw new IllegalStateException (ERROR_NULL_WEB_CTX);
		}
		if (m_templateCtx.getWebMap() == null) {
			LOG.error(ERROR_NULL_WEB_MAP);
			throw new IllegalStateException (ERROR_NULL_WEB_MAP);
		}
		
		RenderedImage preview = null;
		
		try {
			if (m_cachePreview && m_preview != null) {
				if (LOG.isInfoEnabled()) {
					LOG.info(MessageFormat.format(INFO_USING_CACHED_PREVIEW, m_id, m_name));
				}
				return m_preview;
			}
			
			if (LOG.isInfoEnabled()) {
				LOG.info(MessageFormat.format(INFO_GENERATING_PREVIEW, m_id, m_name));
			}
			
			m_mapExporter.setWebMap(m_templateCtx.getWebMap());
			ByteArrayOutputStream baos = new ByteArrayOutputStream();
			m_mapExporter.exportImage(baos);
			
			ParameterBlock pb = new ParameterBlock();
			pb.add(SeekableStream.wrapInputStream(new ByteArrayInputStream(baos.toByteArray()), true));
			
			preview = JAI.create("stream", pb);
			
			if (m_cachePreview) {
				if (LOG.isInfoEnabled()) {
					LOG.info(MessageFormat.format(INFO_CACHING_PREVIEW, m_id, m_name));
				}
				
				m_preview = preview;
			}
			
		} catch (IOException e) {
			LOG.warn(MessageFormat.format(WARN_UNABLE_TO_GEN_PREVIEW, m_id, m_name), e);
		}
		
		return preview;
	}

	/*
	 * (non-Javadoc)
	 * @see com.esri.solutions.jitk.common.templates.map.IWebContextOpenable#open(com.esri.adf.web.data.WebContext)
	 */
	public void open(WebContext ctx) {
		if (ctx == null) {
			throw new NullPointerException ();
		}
		
		WebExtent extent = m_templateCtx.getWebMap().getFullExtent();
		
		Map<String, GISResource> resources = new LinkedHashMap<String,GISResource>(m_templateCtx.getResources());
		Map<String, GISResource> newResources = new LinkedHashMap<String, GISResource>();
		for (Entry<String, GISResource> entry : resources.entrySet()) {
			newResources.put(entry.getKey(), copy(entry.getValue()));
		}
		
		ctx.setResources(newResources);
		ctx.setSpatialReference(m_templateCtx.getSpatialReference());
		ctx.getWebMap().setCurrentExtent(extent);
		ctx.setInit(true);
	}
	
	/**
	 * Sets the {@link WebContext} that contains the {@link GISResource}s
	 * to use for this Map Template.  The Web Context object is required
	 * and cannot be <code>null</code>.  The Web Context must have a
	 * {@link WebMap} associated with it in order to generate the preview
	 * of the Map Template.
	 * 
	 * @param ctx	Reference to Web Context to use for this Map Template,
	 * 				cannot be <code>null</code>.
	 * @throws NullPointerException		Thrown if the <code>ctx</code>
	 * 									argument is <code>null</code>.
	 */
	public void setWebContext (WebContext ctx) {
		if (ctx == null) {
			throw new NullPointerException ();
		}
		m_templateCtx = ctx;
		
		if (!m_templateCtx.isInit()) {
			m_templateCtx.setInit(true);
		}
	}
	
	/**
	 * Returns the {@link WebContext} object that is used for this
	 * Map Template.  May return <code>null</code> if not preceded
	 * by an invocation of {@link #setWebContext(WebContext)}.
	 * 
	 * @return Associated Web Context object.
	 */
	public WebContext getWebContext () {
		return m_templateCtx;
	}
	
	/**
	 * Sets the reference to the {@link WebMapImageExporter} to use
	 * to export the map image from a {@link WebMap}.  The map image
	 * will be used as the Preview of this Map Template.
	 * 
	 * @param exporter  Reference to {@link WebMapImageExporter}, cannot
	 * 					be <code>null</code>.
	 * @throws NullPointerException		Thrown if the <code>exporter</code>
	 * 									argument is <code>null</code>.
	 */
	public void setWebMapImageExporter (WebMapImageExporter exporter) {
		if (exporter == null) {
			throw new NullPointerException();
		}
		m_mapExporter = exporter;
	}

	/**
	 * Returns the flag indicating if the Preview Image should be cached.
	 * Caching of the Preview Image is enabled by default.
	 * 
	 * @return Flag indicating if the Preview Image should be cached.
	 */
	public boolean getCachePreview () {
		return m_cachePreview;
	}
	
	/**
	 * Sets the flag to indicate whether the Preview image should be 
	 * cached internally.  If memory space permits, enabling the cache
	 * should speed up performance.  After setting this flag to <code>true</code>
	 * the next time the {@link #getPreview()} method is invoked the Preview
	 * Image will be cached.
	 * 
	 * @param flag Indicates whether the Preview image should be cached.
	 */
	public void setCachePreview (boolean flag) {
		m_cachePreview = flag;
		if (!m_cachePreview) {
			m_preview = null;
		}
	}

	/*
	 * (non-Javadoc)
	 * @see com.esri.adf.web.data.WebContextInitialize#destroy()
	 */
	public void destroy() {
		m_currentCtx = null;
		m_initialized = false;
	}

	/*
	 * (non-Javadoc)
	 * @see com.esri.adf.web.data.WebContextInitialize#init(com.esri.adf.web.data.WebContext)
	 */
	public void init(WebContext ctx) {
		m_currentCtx = ctx;
		if (!m_initialized) {
			m_initialized = true;
			getPreview();
			open(m_currentCtx);
		}
	}

	/**
	 * Sets the collection of GIS Resource Factories for creating copies
	 * of GIS Resources already in the internal WebContext.  The collection
	 * is a Map indexed by the GIS Resource Class Name.
	 * 
	 * @param factories  Collection of GIS Resource Factories.
	 */
	public void setGisResourceFactories (Map<String, IGISResourceFactory<GISResource>> factories) {
		m_factories = factories;
	}
	
	/**
	 * Creates a copy of an existing GIS Resource.  This method returns
	 * a copy of a GIS Resource that does not exist within any WebContext.
	 * 
	 * @param resource		Reference to a GIS Resource.
	 * @return Copy of GIS Resource.
	 */
	protected GISResource copy (GISResource resource) {
		GISResource copy = null;
		
		if (resource instanceof AGSLocalMapResource) {
			copy = copy((AGSLocalMapResource)resource);
		} else if (resource instanceof AGSMapResource) {
			copy = copy ((AGSMapResource)resource);
		} else if (resource instanceof AIMSMapResource) {
			copy = copy ((AIMSMapResource)resource);
		} else if (resource instanceof WMSMapResource) {
			copy = copy((WMSMapResource)resource);
		} else if (resource instanceof WCSMapResource) {
			copy = copy((WCSMapResource)resource);
		} else if (resource instanceof WFSMapResource) {
			copy = copy((WFSMapResource)resource);
		} else {
			copy = resource;
		}
		
		return copy;
	}
	
	/**
	 * Creates a copy of an {@link AGSMapResource}.  This method
	 * will use the appropriate GIS Resource Factory to create
	 * a new object and then will initialize relevant property values
	 * on the copied GIS Resource.
	 * 
	 * @param resource		GIS Resource to copy
	 * @return Copy of specified GIS Resource.
	 */
	protected AGSMapResource copy (AGSMapResource resource) {
		AGSMapResource copy = null;
		
		IGISResourceFactory<GISResource> factory = 
			m_factories.get(AGSMapResource.class.getName());
		
		if (factory == null) {
			return null;
		}
		
		copy = (AGSMapResource) factory.createResource();
		copy.setAlias(resource.getAlias());
		copy.setEndPointURL(resource.getEndPointURL());
		copy.setUser(resource.getUser());
		
		return copy;
	}
	
	/**
	 * Creates a copy of an {@link AGSLocalMapResource}.  This method
	 * will use the appropriate GIS Resource Factory to create
	 * a new object and then will initialize relevant property values
	 * on the copied GIS Resource.
	 * 
	 * @param resource		GIS Resource to copy
	 * @return Copy of specified GIS Resource.
	 */
	protected AGSLocalMapResource copy (AGSLocalMapResource resource) {
		AGSLocalMapResource copy = null;
		
		IGISResourceFactory<GISResource> factory = 
			m_factories.get(AGSLocalMapResource.class.getName());
		
		if (factory == null) {
			return null;
		}
		
		copy = (AGSLocalMapResource) factory.createResource();
		copy.setAlias(resource.getAlias());
		copy.setHosts(resource.getHosts());
		copy.setServerObjectName(resource.getServerObjectName());
		copy.setClusterType(resource.getClusterType());
		copy.setFailRecheckValue(resource.getFailRecheckValue());
		copy.setUser(resource.getUser());
		
		return copy;
	}
	
	/**
	 * Creates a copy of an {@link AIMSMapResource}.  This method
	 * will use the appropriate GIS Resource Factory to create
	 * a new object and then will initialize relevant property values
	 * on the copied GIS Resource.
	 * 
	 * @param resource		GIS Resource to copy
	 * @return Copy of specified GIS Resource.
	 */
	protected AIMSMapResource copy (AIMSMapResource resource) {
		AIMSMapResource copy = null;
		
		IGISResourceFactory<GISResource> factory = 
			m_factories.get(AIMSMapResource.class.getName());
		
		if (factory == null) {
			return null;
		}
		
		copy = (AIMSMapResource) factory.createResource();
		copy.setAlias(resource.getAlias());
		copy.setHostName(resource.getHostName());
		copy.setPassword(resource.getPassword());
		copy.setPasswordEncrypted(resource.isPasswordEncrypted());
		copy.setPort(resource.getPort());
		copy.setServiceName(resource.getServiceName());
		copy.setUserName(resource.getUserName());
		
		return copy;
	}
	
	/**
	 * Creates a copy of an {@link WMSMapResource}.  This method
	 * will use the appropriate GIS Resource Factory to create
	 * a new object and then will initialize relevant property values
	 * on the copied GIS Resource.
	 * 
	 * @param resource		GIS Resource to copy
	 * @return Copy of specified GIS Resource.
	 */
	protected WMSMapResource copy (WMSMapResource resource) {
		WMSMapResource copy = null;
		
		IGISResourceFactory<GISResource> factory = 
			m_factories.get(WMSMapResource.class.getName());
		
		if (factory == null) {
			return null;
		}
		
		copy = (WMSMapResource) factory.createResource();
		
		copy.setAlias(resource.getAlias());
		copy.setWmsURL(resource.getWmsURL());
		copy.setWmsVersion(resource.getWmsVersion());
		
		return copy;
	}
	
	/**
	 * Creates a copy of an {@link WCSMapResource}.  This method
	 * will use the appropriate GIS Resource Factory to create
	 * a new object and then will initialize relevant property values
	 * on the copied GIS Resource.
	 * 
	 * @param resource		GIS Resource to copy
	 * @return Copy of specified GIS Resource.
	 */
	protected WCSMapResource copy (WCSMapResource resource) {
		WCSMapResource copy = null;
		
		IGISResourceFactory<GISResource> factory = 
			m_factories.get(WCSMapResource.class.getName());
		
		if (factory == null) {
			return null;
		}
		
		copy = (WCSMapResource)factory.createResource();
		copy.setAlias(resource.getAlias());
		copy.setCoverage(resource.getCoverage());
		copy.setEndPointURL(resource.getEndPointURL());
		
		return copy;
	}
	
	/**
	 * Creates a copy of an {@link WFSMapResource}.  This method
	 * will use the appropriate GIS Resource Factory to create
	 * a new object and then will initialize relevant property values
	 * on the copied GIS Resource.
	 * 
	 * @param resource		GIS Resource to copy
	 * @return Copy of specified GIS Resource.
	 */
	protected WFSMapResource copy (WFSMapResource resource) {
		WFSMapResource copy = null;
		
		IGISResourceFactory<GISResource> factory = 
			m_factories.get(WFSMapResource.class.getName());
		
		if (factory == null) {
			return null;
		}
		
		copy = (WFSMapResource) factory.createResource();
		
		copy.setAlias(resource.getAlias());
		copy.setEndPointURL(resource.getEndPointURL());
		
		return copy;
	}
}