barcode printer in vb.net Figure 6.6 Our custom button and layout nodes on display in Java

Encoder QR Code JIS X 0510 in Java Figure 6.6 Our custom button and layout nodes on display

The DemonstrateMainPower method, as a public member of your class, can be called either by code within the class, or by any code referencing an instance of your class. This method includes a single parameter, strengthFactor, through which calls to the method send in data arguments. You can jump out of a sub method at any time using the Return statement, or the older pre-.NET Exit Sub statement. Function methods Function methods are just like sub methods, but they support a return value. You define the data type of the return value with an As clause at the end of the function definition. You can assign the return value using the Return statement, or by assigning the function name directly within the code.

More manipulations of strings with the GD module can be found in chapter 11, as well as examples on how to align and position strings precisely.

) : Void { var freq = for(a in [0..gridDim]) 0; for(pos in [0..<gridDim]) { var val = grid[ func(group,pos) ]; if(val > 0) { freq[val]++; } } for(pos in [0..<gridDim]) { var idx = func(group,pos); var val = grid[idx]; clashes[idx] = clashes[idx] or (freq[val]>1); } } function checkStats() : Void { numEmpty = 0; numClashes = 0; for(idx in [0..<gridSize]) { if(grid[idx]==0) numEmpty++; if(clashes[idx]) numClashes++; } }

Even when multithreaded code provides a demonstrable performance benefit, it s very hard to get right. We ve already seen a few bizarre behaviors in some extremely simple examples. Achieving correct behavior in a real concurrent system can be very challenging. So we ll look at two of the most common classes of pitfalls before examining some strategies for avoiding them.

public void paintChart(String sym, int currentPrice, int historicPrice) { Graphics.drawRectangle(5,60,155,70,Graphics.ERASE,0); Graphics.drawString(sym + " Performance",5,60,Graphics.PLAIN); Graphics.drawString("current vs. historic",5,73,Graphics.PLAIN); Graphics.drawString("$" + currentPrice, 5, 85, Graphics.PLAIN); Graphics.drawString("$" + historicPrice, 5, 110, Graphics.PLAIN); int[] prices = {currentPrice, historicPrice}; int[] lengths = determineLengths(prices); Graphics.drawRectangle (START_X_POSITION, START_Y_CURRENT, lengths[0],BAR_HEIGHT, Graphics.PLAIN, 0); Graphics.drawRectangle (START_X_POSITION, START_Y_HISTORIC, lengths[1],BAR_HEIGHT, Graphics.PLAIN, 0);

Because we are dealing with a value type, the thirdElementInArray local variable gets a copy of the value in the array. This means that the code can change the local variable without altering the element in the array. Compare that with similar code working on the array from Example 7-10:

Summary