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04.16.2008 at 05:20PM PDT, ID: 23329379
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Java generics

Asked by corey_mcm in Java Programming Language

Tags: Java

I have a java class which is used to create a list of points from a BLOB in a MS SQL database. This is then used by a charting utility to generate a graph.

Two different methods are used, one for a 2D set of data to plot, and another for multiple 2D data sets where more than one line is graphed. The first method seems to work ok, but the second doesn't

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public float[][] read2D(byte[] byteArray, float scaling)
        throws IOException
    {
        int				  structSize = 8;   // 2 floats
        int				  pointCount = byteArray.length / structSize;
        float[][]		  floatArray = new float[pointCount][2];
        LEDataInputStream dis		 = new LEDataInputStream(new ByteArrayInputStream(byteArray));
        
        for (int i = 0; i < pointCount; i++)
        {
            Float xValueReadIn = dis.readFloat();
            Float yValueReadIn = dis.readFloat();
//
// Check the x value
//
            if (xValueReadIn.isNaN())
            {
                floatArray[i][0] = 0;   
            }	 
            else
            {
                floatArray[i][0] = xValueReadIn.floatValue();   
            }
//
// Check the y value
//
            if (yValueReadIn.isNaN())
            {
                floatArray[i][1] = 0;   
            }	 
            else
            {
                floatArray[i][1] = yValueReadIn.floatValue();   
            }
        }
 
        return floatArray;
    }
 
/**
 *
 * readDouble2D(byte[] byteArray)
 *
 * Two 2-dimensional trace point arrays is an array of structures.
 * x1,y1a,y1b,
 * x2,y2a,y2b,
 * ...
 * xn,yna,ynb
 *
 */
    public Vector<Float>[] readDouble2D(byte[] byteArray)
        throws IOException
    {
        return readDouble2D(byteArray, 1);
    }
 
    public Vector<Float>[] readDouble2D(byte[] byteArray, float scaling)
        throws IOException
    {
        int				    structSize  = 12;   // 3 floats
        int				    pointCount  = byteArray.length / structSize;
        List<Vector<Float>> vectorArray = new ArrayList<Vector<Float>>(pointCount);
        LEDataInputStream   dis		  = new LEDataInputStream(new ByteArrayInputStream(byteArray));
        
        for (int i = 0; i < pointCount; i++)
        {
            Vector<Float> values = new Vector<Float>(3);
//
// No scaling for x value
//
 
            values.add(new Float(dis.readFloat() * scaling));
            
            for (int j = 0; j < 2; j++)
            {
                values.add(new Float(dis.readFloat() * scaling));
            }
            
            vectorArray.add(values);
        }
        
        return (Vector<Float>[])vectorArray.toArray();
    }
 
/*
 * ---------------------------
 * Here is the misbehaving class
 */
public Map<String, Float>[] read2DMultiPoint(byte[] byteArray, int points, String[] hashNames, float scaling)
        throws IOException
    {
        int                                              structSize = 4 * points;
        int                                              pointCount = byteArray.length / structSize;
        List<Map<String, Float>> mapArray   = new ArrayList<Map<String, Float>>(pointCount);
        LEDataInputStream                dis            = new LEDataInputStream(new ByteArrayInputStream(byteArray));
        
        for (int i = 0; i < pointCount; i++)
        {
            HashMap<String, Float> pointMap = new HashMap<String, Float>(points);
//
// No scaling for x value
//
            pointMap.put(hashNames[0], new Float(dis.readFloat()));
            
            for (int j = 1; j < points; j++)
            {
                pointMap.put(hashNames[j], new Float(dis.readFloat() * scaling));
            }
            
            mapArray.add(pointMap);
        }
            
        return (Map<String, Float>[])mapArray.toArray();
    }
[+][-]04.16.2008 at 11:22PM PDT, ID: 21374592

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[+][-]04.16.2008 at 11:38PM PDT, ID: 21374669

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[+][-]04.16.2008 at 11:39PM PDT, ID: 21374673

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[+][-]04.16.2008 at 11:41PM PDT, ID: 21374682

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[+][-]04.16.2008 at 11:49PM PDT, ID: 21374704

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[+][-]04.16.2008 at 11:51PM PDT, ID: 21374717

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[+][-]04.17.2008 at 12:04AM PDT, ID: 21374772

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About this solution

Zone: Java Programming Language
Tags: Java
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Solution Provided By: Bart_Cr
Participating Experts: 3
Solution Grade: A
 
 
[+][-]04.17.2008 at 01:18AM PDT, ID: 21375099

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