weboverview.java

esri的ArcGIS Server超级学习模板程序（for java）

package com.esri.solutions.jitk.web.data;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

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

import com.esri.adf.web.data.OverviewFunctionality;
import com.esri.adf.web.data.WebContext;
import com.esri.adf.web.data.geometry.WebExtent;
import com.esri.adf.web.util.ImageUtil;
import com.esri.adf.web.util.WebUtil;

/**
 * Extension of the {@link com.esri.adf.web.data.WebOverview} class.
 * This provides some new features of the Overview Map.  In the base 
 * implementation, the background map would never zoom, but instead remained
 * static at the full extent.  As the user panned or zoomed on the main map,
 * the rectangle would be updated.
 * 
 * <p>
 * This Overview Map will not remain static.  It will zoom if necessary.  If the
 * ratio between the map's extent and the overview map's extent is not within
 * a configurable range, then the overview map will be redrawn accordingly.  If the
 * user pans to an area outside of the current extent of the overview map, then 
 * the overview map will be redrawn.
 * </p>
 *
 * <p>
 * The MinExtentRatio property is the minimum ratio between the Map Extent and the Overview
 * Map extent that is allowed before the Overview Map needs to be redrawn.  Example, if the
 * MinExtentRatio property has a value of 2.0, then once the width of the Overview Map divided by
 * the width of the Map is less than 2.0, then the Overview Map will be redrawn.  This prevents the
 * highlighted region from becoming too big on the Overview Map.  The MinExtentRatio cannot be equal to
 * or less than 0.0.
 * </p>
 * 
 * <p>
 * The MaxExtentRatio property is the maximum ratio between the Map Extent and the Overview Map
 * extent that is allowed before the Overview Map needs to be redrawn.  Example, if the
 * MaxExtentRatio property has a value of 8.0, then once the width of the Overview Map divided by
 * the width of the Map is greater than 8.0, then the Overview Map will be redrawn.  This prevents
 * the highlighted region from becoming too small on the Overview Map.  The MaxExtentRatio cannot be
 * equal to or less then 0.0.
 * </p>
 */
public class WebOverview extends com.esri.adf.web.data.WebOverview {

	/**
	 * Unique Version ID of this class.  Used for serialization purposes.
	 */
	private static final long serialVersionUID = -3815139545421274948L;

	/**
	 * Logger to use to log messages from this class.
	 */
	private static final Logger LOG = LogManager.getLogger(WebOverview.class);
	
	/**
	 * Minimum ratio between the Map Extent and the Overview Map Extent.  If the
	 * ratio is less than this value then the Overview Map is redrawn.
	 */
	private double minExtentRatio;
	
	/**
	 * Maximum ratio between the Map Extent and the Overview Map Extent.  If the
	 * ratio is greater than this value then the Overview Map is redrawn.
	 */
	private double maxExtentRatio;
	
	/**
	 * Keeps track of the enabled/disabled state of the Overview Functionalities
	 * before any changes are made.
	 */
	private final Map<OverviewFunctionality, Boolean> m_ovFuncState;
	
	/**
	 * Default value for the Minimum Extent Ratio property.
	 * 
	 * @see #setMinExtentRatio(double)
	 */
	public static final double DEFAULT_MINIMUM_EXTENT_RATIO = 2.0D;
	
	/**
	 * Default value for the Maximum Extent Ratio property.
	 * 
	 * @see #setMaxExtentRatio(double)
	 */
	public static final double DEFAULT_MAXIMUM_EXTENT_RATIO = 8.0D;
	
	/**
	 * Default value for the Image Format property
	 * 
	 * @see #setImageFormat(String)
	 */
	public static final String DEFAULT_IMAGE_FORMAT = "png";
	
	/**
	 * Constructs a new WebOverview object.  The MinimumExtentRatio property
	 * is set to {@link #DEFAULT_MINIMUM_EXTENT_RATIO} and the MaximumExtentRatio
	 * property is set to {@link #DEFAULT_MAXIMUM_EXTENT_RATIO}.
	 * 
	 */
	public WebOverview (){
		LOG.info("Constructing a new " + this.getClass().getName() + " object.");
		setMinExtentRatio(DEFAULT_MINIMUM_EXTENT_RATIO);
		setMaxExtentRatio(DEFAULT_MAXIMUM_EXTENT_RATIO);
		setImageFormat(DEFAULT_IMAGE_FORMAT);
		setShowFullExtent(false);
		m_ovFuncState = new HashMap<OverviewFunctionality, Boolean>();
	}
	
	/**
	 * Sets the ShowFullExtent property to the desired value.  The method argument
	 * must be <code>false</code> in order for this Overview Map to function properly.
	 * 
	 * @param showFullExtent		Must be <code>false</code>.
	 * 
	 * @throws IllegalArgumentException		Thrown if the <code>showFullExtent</code> argument
	 * 										is <code>false</code>.
	 */
	public void setShowFullExtent (boolean showFullExtent) {
		LOG.debug("Attempting to set ShowFullExtent to " + showFullExtent);
		
		if (showFullExtent) {
			throw new IllegalArgumentException ("ShowFullExtent property must be false for this Overview Map to work as desired");
		}
		
		super.setShowFullExtent(showFullExtent);
		LOG.debug("Successfully set ShowFullExtent to " + showFullExtent);
	}
	
	/**
	 * Sets the ImageFormat property on this Overview Map.  The ImageFormat property specifies what
	 * type of image encoding that the Overview Map image should be drawn, such as JPG, PNG, etc.  
	 * 
	 * @param format		Encoding to use when exporting the image, cannot be
	 * 						<code>null</code>.
	 * 
	 * @throws NullPointerException		Thrown if the <code>format</code> argument is
	 * 									<code>null</code>.
	 */
	public void setImageFormat (String format) {
		LOG.debug("Attempting to set ImageFormat to " + format);
		
		if (format == null) {
			throw new NullPointerException ();
		}
		
		super.setImageFormat(format);
		LOG.debug("Successfully set ImageFormat to " + format);
	}
	
	/**
	 * Override of the {@link com.esri.adf.web.data.WebOverview#update(WebContext, Object)}
	 * method.  This method will determine if the Overview Map image needs to be redrawn
	 * and exported and will calculate the new extent of the Overview Map.
	 * 
	 * @param context			Reference to the {@link WebContext}.  This method does not
	 * 							use this argument.
	 * @param arg				Argument passed to the {@link WebContext#refresh(Object)} method
	 * 							when invoked.  This method ignores this argument.
	 */
	public void update(WebContext context, Object arg) {
		LOG.info("Updating Overview Map");
		if (shouldRedrawOvMap() || imageBytes == null) {
			LOG.info("Overview Map needs to be redrawn");
			calculateNewDrawExtent();
			imageBytes = null;
		}
		reloadImageRectangle();
		updateOvFuncState();
	}

	/**
	 * Override of the {@link com.esri.adf.web.data.WebOverview#init(WebContext)} method.
	 * This method will be invoked by the ADF framework.
	 * This method will call the super class's init method.  Then it will calculate a new
	 * extent for the Overview Map based on the referenced {@link WebMap} object.
	 * 
	 * @param context			Reference to the {@link WebContext}.
	 */
	public void init(WebContext context) {
		LOG.info("Initializing Overview Map");
		super.init(context);
		calculateNewDrawExtent();
		reloadImageRectangle();
		
		updateOvFuncState();
	}

	

	/**
	 * Returns value of the MinExtentRatio property.  If the {@link #setMinExtentRatio(double)} method
	 * has not been invoked, then this method will return {@link #DEFAULT_MINIMUM_EXTENT_RATIO}.
	 * See the class documentation for more information on the MinExtentRatio property.
	 * 
	 * @return Value of MinExtentRatio property.
	 */
	public double getMinExtentRatio() {
		return minExtentRatio;
	}

	/**
	 * Sets the value of the MinExtentRatio property.  See the class documentation for more information
	 * on the MinExtentRatio property.
	 * 
	 * @param minExtentRatio		Value of the MinExtentRatio property, must be greater than 0.0.
	 * 
	 * @throws IllegalArgumentException		Thrown if the <code>minExtentRatio</code> argument is less than
	 * 										or equal to 0.0.
	 */
	public void setMinExtentRatio(final double minExtentRatio) {
		LOG.debug("Attempting to set MinExtentRatio to " + minExtentRatio);
		
		if (minExtentRatio <= 0.0) {
			throw new IllegalArgumentException("MinExtentRatio cannot be less than 0.0");
		}
		this.minExtentRatio = minExtentRatio;
		
		LOG.debug("Successfully set MinExtentRatio to " + minExtentRatio);
	}

	/**
	 * Returns value of the MaxExtentRatio property.  If the {@link #setMaxExtentRatio(double)} method