simplegeodata.java

geotools的源码

package uk.ac.leeds.ccg.geotools;

import java.util.*;
import java.io.*;

/**
 * A concrete implementation of the GeoData interface, it is suitable for most
 * uses and may be extended for more specialist GeoData implementations.
 * 
 * @author James Macgill JM
 */

public class SimpleGeoData implements GeoData,Serializable{
    /**
     * Stores the name of this GeoData, returned by getName.
     */
    private String name="Unknown";
		private int type = GeoData.FLOATING;
    double min=Double.POSITIVE_INFINITY,max=Double.NEGATIVE_INFINITY;
    Hashtable data;
    double missingValue = -99999;
    int missingCount=0;
    
    /**
     * the default constructor for SimpleGeoData
     * @author James Macgill JM
     */
    public SimpleGeoData(){
        data=new Hashtable();
    }
    
    /**
     * Constructs a SimpleGeoData by pulling the values from a Hashtable.<br>
     * The hashtable should be built with Integer objects holding ids as keys and
     * Double objects or strings for the values.
     * 
     * @author James Macgill JM
     * @param h A hashtable containg the id keys and values for this SimpleGeoData object
     */
    public SimpleGeoData(Hashtable h){
        data = h;
        doMinMax();
    }
    
    /**
     * Updates the values for min and max that are returned by getMin and getMax.<br>
     * This method iterates through all of the data stored to find the current Min and Max values.
     *
     **/
    public void doMinMax(){
        min=Double.MAX_VALUE;
        max=Double.MIN_VALUE;
        missingCount=0;
        for (Enumeration e = data.elements() ; e.hasMoreElements() ;) {
            double value = ((Double)e.nextElement()).doubleValue(); 
            if(value!=missingValue){
                min=Math.min(value,min);
                max=Math.max(value,max);
            }
            else{
                missingCount++;
            }
        }
    }
    
    
    
    /**
     * Not all posible ids will have a value stored in the GeoData object, so when a call is made to getValue with an id that is
     * not stored a special value is returned to signify that a value for this id is missing.<br>
     * By default that value is set to MISSING, however this behavoir can be changed by calling this method with a new value.<br>
     * 
     * @see #getMissingValueCode
     * @author James Macgill JM
     * @param mv A double containing the new value to represent missing data.
     */
    public void setMissingValueCode(double mv){
        missingValue = mv;
        doMinMax();
    }
    
    
    /**
     * Not all posible ids will have a value stored in the GeoData object, so when a call is made to getValue with an id that is
     * not stored a special value is returned to signify that a value for this id is missing.<br>
     * A call to this method will return the current code in use to represent that situation.<br>
     *
     * @see #setMissingValueCode
     * @author James Macgill JM
     * @return double The current value representing missing data.
     */    
    public double getMissingValueCode(){
        return missingValue;
    }
    
    /**
     * Stores the id/value pair into this GeoData.<br>
     * If the id specifed already has a value associated with it then the old value is returned.<br>
     * If the id is a new one then the returned value will match the current missingValueCode
     *
     * @author James Macgill JM
     * @param id An int holding the id to set the value for.
     * @param value The value to associate with the specifed id.
     * @return The old value associated with id, or missingValueCode if the id was previusly not set.
     */
    public double setValue(int id,double value){
        if(value!=missingValue){
            min=Math.min(value,min);
            max=Math.max(value,max);
        }
        else{
            missingCount++;
        }
        Double old = (Double)data.put(new Integer(id),new Double(value));
        
        if (old!=null){
            if(old.doubleValue()==missingValue){missingCount--;}
            return old.doubleValue();
        }
        return missingValue;
    }
    
    /**
     * Returns the number of values stored that equal the current missing value code.
     */
    public int getMissingCount(){
        return missingCount;
    }
    
    /**
     * Stores the id/text pair into this GeoData.<br>
     * If the id specifed already has text associated with it then the old text is returned.<br>
     * If the id is a new one then the returned String will be null
     *
     * @author James Macgill JM
     * @param id An int holding the id to set the value for.
     * @param text The String to associate with the specifed id.
     * @return The old text associated with id, or null if the id was previusly not set.
     */
    public String setText(int id,String text){
				setDataType(GeoData.CHARACTER);
        String old = (String)data.put(new Integer(id),text);
        return old;
    }
    
    /**
     * All GeoData objects can have a name associated with them.<br>
     * Typicaly the name will match the Column heading from which the data came from.<br>
     * Names can be important when the GeoData is used in thematic maps as this is the
     * name that will be placed in the key by default.<br>
     *
     * @author James Macgill JM
     * @param name_ The name to be associated with this GeoData.
     */    
    public void setName(String name_) {
        name = name_;
    }
        
    /**
     * All GeoData objects can have a name associated with them.<br>
     * Typicaly the name will match the Column heading from which the data came from.<br>
     * Names can be important when the GeoData is used in thematic maps as this is the
     * name that will be placed in the key by default.<br>
     * @author James Macgill JM
     * @return String The name associated with this GeoData.
     */
    public String getName(){
        return name;
    }
    
    /**
     * look up a value for the given id
     * if the GeoData object is completly empty with no values set at all
     * then it bounces the id back to the caller.
     * this is an experimental new behavior for getValue 
     */
    public double getValue(int id){
        if(data.isEmpty()){return id;}
        try{
            Double d = (Double)data.get(new Integer(id));
            if (d!=null){
                return d.doubleValue();
            }
        }
        catch(NumberFormatException e){
        return missingValue;
				}
        return missingValue;
    }
    /**
     * A quick statistic relating to the values stored in the GeoData object.<br>
     * 
     * @author James Macgill JM
     * @return double The smallest value currently stored in this GeoData.  The missingValueCode is not included in this test.
     */
    public double getMin(){
        return min;
    }
    /**
     * A quick statistic relating to the values stored in the GeoData object.<br>
     * 
     * @author James Macgill JM
     * @return double The largest value currently stored in this GeoData.  The missingValueCode is not included in this test.
     */
    public double getMax(){
        return max;
    }
    /**
     * The total number of stored id/value pairs stored in this GeoData.
     * @author James Macgill JM
     * @return int The number of values stored in this GeoData.
     */
    public int getSize(){
        return data.size();
    }
    /**
     * Looks up and retreves a string for the specifed feature id.<br>
     * Used for example by the ToolTip feature in Themes to provide tool tip text for each feature.
     *
     * @author James Macgill JM
     * @param id An int specifying the feature to retreve the text for.
     * @return String A piece of text for the chosen feature id.  If no id matches then an empty string should be returned " "
     */
    public String getText(int id){
        Object o = data.get(new Integer(id));
        if (o!=null){
            return o.toString();
        }
        return (" ");//if there is no space this returns a null
    }
    /**
     * In order to allow systems to iterate through all of the data contained within the GeoData object this
     * method provides a list of all of the IDs which have associated values stored.
     *
     * @author James Macgill JM
     * @return Enumeration An enumeration of all of the IDs which can then be iterated through.
     */
    public Enumeration getIds(){
        return data.keys();
    }
    
    /**
     * Returns the name of the GeoData object.  This can be handy when you want to include
     * GeoData objets in lists.
     * @return Strin the name of this GeoData
     */
    public String toString(){
        return name;
    }
	  public int getDataType(){
			return type;
		}
		public void setDataType(int t){
			type=t;
		}
		public void clear(){
			data = new Hashtable();
			doMinMax();
		}
}