salesforce apex + vf page + Google Chart II

/* This class contains the encoding algorithm for use with the
Google chartAPI. */

public class YUT_GoogleDataEncoding {
// Exceptions to handle any erroneous data
public class EncodingException extends Exception {}
public class UnsupportedEncodingTypeException
extends Exception {}

/* The encoding map which takes an integer key and returns the
respective encoding value as defined by Google.
This map is initialized in init() */
private Map<Integer, String> encodingMap { get; set; }

/* The maximum encoding value supported for the given encoding
type. This value is set during init() */
private Integer encodingMax { get; set; }

/* The minimum encoding value supported for the given encoding
type. This value is set during init() */
private Integer encodingMin { get; set; }

/* The encoding type according to Google's API. Only SIMPLE
is implemented. */
public enum EncodingType { TEXT, SIMPLE, EXTENDED }

/* The minimum value to use in the generation of an encoding
value. */
public Integer min { get; private set; }

/* The maximum value to use in the generation of an encoding
value. */
public Integer max { get; private set; }

// The encoding type according to the API defined by Google
public EncodingType eType { get; private set; }

// Corresponds to the data set provided by the page
public String dataSet { get; set; }

// Corresponds to the type of graph selected on the page
public String graph { get; set; }

// The URL that renders the Google Chart
public String chartURL { get; set; }

// Indicates whether the chart should be displayed
public Boolean displayChart { get; set; }

public YUT_GoogleDataEncoding() {
min = 0;
max = 61;
eType = EncodingType.SIMPLE;
displayChart = false;
init();
}

public PageReference create() {
String[] dataSetList = dataSet.split(',', 0);
String mappedValue = 'chd=s:';

chartURL = 'http://chart.apis.google.com/chart?chs=600x300'
+ '&chtt=Time+vs|Distance&chxt=x,y,x,y'
+ '&chxr=0,0,10,1|1,0,65,5'
+ '&chxl=2:|Seconds|3:|Meters';

if (graph.compareTo('barChart') == 0)
{
chartURL += '&cht=bvs';
}
else if (graph.compareTo('lineChart') == 0)
{
chartURL += '&cht=ls';
}
else
{
throw new EncodingException('An unsupported chart type'
+ 'was selected: ' + graph + ' does not exist.');
}

for(String dataPoint : dataSetList)
{
mappedValue +=
getEncode(Integer.valueOf(dataPoint.trim()));
}

chartURL += '&' + mappedValue;
displayChart = true;
return null;
}

/* This method returns the encoding type parameter value that
matches the specified encoding type. */
public static String getEncodingDescriptor(EncodingType t) {
if(t == EncodingType.TEXT) return 't';
else if(t == EncodingType.SIMPLE) return 's';
else if(t == EncodingType.EXTENDED) return 'e';
else return '';
}

/* This method takes a given number within the declared
range of the encoding class and encodes it according to the
encoding type. If the value provided fall outside of the
declared range, an EncodingException is thrown. */
public String getEncode(Integer d) {
if(d > max || d < min) {
throw new EncodingException('Value provided ' + d
+ ' was outside the declared min/max range ('
+ min + '/' + max + ')');
}
else {
return encodingMap.get(d);
}
}

/* This method initializes the encoding map which is then
stored for expected repetitious use to minimize statement
invocation. */
private void init() {
if(eType == EncodingType.SIMPLE) {
encodingMax = 61;
encodingMin = 0;
encodingMap = new Map<Integer, String>();
encodingMap.put(0,'A');
encodingMap.put(1,'B');
encodingMap.put(2,'C');
encodingMap.put(3,'D');
encodingMap.put(4,'E');
encodingMap.put(5,'F');
encodingMap.put(6,'G');
encodingMap.put(7,'H');
encodingMap.put(8,'I');
encodingMap.put(9,'J');
encodingMap.put(10,'K');
encodingMap.put(11,'L');
encodingMap.put(12,'M');
encodingMap.put(13,'N');
encodingMap.put(14,'O');
encodingMap.put(15,'P');
encodingMap.put(16,'Q');
encodingMap.put(17,'R');
encodingMap.put(18,'S');
encodingMap.put(19,'T');
encodingMap.put(20,'U');
encodingMap.put(21,'V');
encodingMap.put(22,'W');
encodingMap.put(23,'X');
encodingMap.put(24,'Y');
encodingMap.put(25,'Z');
encodingMap.put(26,'a');
encodingMap.put(27,'b');
encodingMap.put(28,'c');
encodingMap.put(29,'d');
encodingMap.put(30,'e');
encodingMap.put(31,'f');
encodingMap.put(32,'g');
encodingMap.put(33,'h');
encodingMap.put(34,'i');
encodingMap.put(35,'j');
encodingMap.put(36,'k');
encodingMap.put(37,'l');
encodingMap.put(38,'m');
encodingMap.put(39,'n');
encodingMap.put(40,'o');
encodingMap.put(41,'p');
encodingMap.put(42,'q');
encodingMap.put(43,'r');
encodingMap.put(44,'s');
encodingMap.put(45,'t');
encodingMap.put(46,'u');
encodingMap.put(47,'v');
encodingMap.put(48,'w');
encodingMap.put(49,'x');
encodingMap.put(50,'y');
encodingMap.put(51,'z');
encodingMap.put(52,'0');
encodingMap.put(53,'1');
encodingMap.put(54,'2');
encodingMap.put(55,'3');
encodingMap.put(56,'4');
encodingMap.put(57,'5');
encodingMap.put(58,'6');
encodingMap.put(59,'7');
encodingMap.put(60,'8');
encodingMap.put(61,'9');
}
}
}

<apex:page controller="YUT_GoogleDataEncoding">
<apex:form >
<apex:pageBlock title="Create a Google Chart for Time and Distance">
<apex:outputLabel value="Enter data set, separated by commas: "
for="dataInput"/><br/>
<apex:inputTextArea id="dataInput" title="First Data Point"
value="{!dataSet}" rows="3" cols="50"/><br/>
<apex:selectRadio value="{!graph}"
layout="pageDirection">
<apex:selectOption itemValue="barChart"
itemLabel="Horizontal Bar Chart"/>
<apex:selectOption itemValue="lineChart"
itemLabel="Line Chart"/>
</apex:selectRadio>
<apex:commandButton action="{!create}"
value="Create"/>
</apex:pageBlock>
</apex:form>
<apex:image url="{!chartURL}" alt="Sample chart"
rendered="{!displayChart}"/>
</apex:page>