Base lesson 2, step 6: Print out the report

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Last revision of this document:
2006-03-03

This step of the tutorial * reads the content of the TextArea and * prints the text out to a printer.

`Preface:`

There is a lot of functionality for printing offered in Java (since Version 1.4). This tutorial shows a very basic method of printing in Java which will also work with Java Version 1.1 and later.

`Credits:`

I took the guideline (in German) for a simple print example from: http://www.addisonwesley.de/Service/Krueger/kap15004.htm.

Prerequisites:

JS_Base02f, Step 5 – Run SQL-commands against the database completed – and its prerequisites too.
Basic knowledge of Java programming language; particular the usage of libraries.

`Code for processing after the click onto button 'Print the report':`

As described in steps before, the 'click' leads to a call of the method protected static void handleEvent(JS_DBLoad parmCallingFrame, ActionEvent parmActionEvent). To react to a click onto button 'Print the report', a method must be called when the 'ActionCommand' shows a click onto the button,

What method will be called is implemented with the following line of code: public class JS_DBLoad__Action_Handler { protected static void handleEvent(JS_DBLoad parmCallingFrame, ActionEvent parmActionEvent){ /* * Extract the action-command (in form of a String) that triggered the Event from the Event */ String cmd = parmActionEvent.getActionCommand().trim(); /* * Compare the String with the action-command and call the adjacent method */ if(cmd.equals(„btn_Select“)) processSelectFile(parmCallingFrame); if(cmd.equals(„btn_Start“)) processDBLoad(parmCallingFrame); if(cmd.equals(„btn_Printt“)) processPrint(parmCallingFrame); } protected static void processSelectFile(JS_DBLoad parmCallingFrame){ /*
The implementation of the above code will lead to an error as the method protected static void processSelectFile(JS_DBLoad parmCallingFrame) is not found. The code for it will be implemented in the class JS_DBLoad__Action_Handler. The development is documented in several steps.
First, the messages written to the TextArea 'Report' on the GUI are read and split up into single lines: protected static void processPrint(JS_DBLoad parmCallingFrame){ /* * Content of the TextArea on the GUI as a text-stream */ String strTextAreaContent = parmCallingFrame.get_txt_Report().getText(); /* Position of the 'NewLine' character after the first line within the text-stream */ int intNewLinePosition; /* First line within the stream (Text till the 'NewLine' character. * This line will be printed */ String strLineToBePrinted; /* * Loop to split up the text-stream into single lines; * Extra code for the first line - to catch the case that the text-stream is empty; * then a while-loop for the following lines */ intNewLinePosition = strTextAreaContent.indexOf(„\n“); while (intNewLinePosition >= 0) { /* Text before the 'NewLine' character is split-off */ strLineToBePrinted = strTextAreaContent.substring(0, intNewLinePosition); /* Text after the 'NewLine' character is kept */ strTextAreaContent = strTextAreaContent.substring(intNewLinePosition + 1); // // Code for printing is inserted here; // temporarily the single line is displayed on the GUI parmCallingFrame.get_txt_Report().append(„Single Line split off: „ + strLineToBePrinted + „\n“); // /* Position of the next 'NewLine' character */ intNewLinePosition = strTextAreaContent.indexOf(„\n“); } }
To see if the code was typed error-free it is a good time now to see an intermediate result. Please remind to save the code just typed before running the application by selecting >Run>Run As>Java Application. Do not forget to 'Select Input File' and select the (till now empty) file with the SQL-commands - otherwise the XML-file with the parameters will not be loaded ! Click the button 'Start SQL execution' thereafter. To save some space the screenshot is skipped.
Now, the code for selecting a printer and printing the Lines is implemented. protected static void processPrint(JS_DBLoad parmCallingFrame){ /* * Content of the TextArea on the GUI as a text-stream */ String strTextAreaContent = parmCallingFrame.get_txt_Report().getText(); /* Position of the 'NewLine' character after the first line within the text-stream */ int intNewLinePosition; /* First line within the stream (Text till the 'NewLine' character. * This line will be printed */ String strLineToBePrinted; /* * Variables used for printing the text */ /* Page- and Line-Counter to start a new page and print the page-number on top of the sheet / int intPageCount = 1; int intLineCount = 1; /* Printer-specific variables */ Frame f = new Frame(); PrintJob pJob = f.getToolkit().getPrintJob(f, „JS_DBLoad - Printer Selection“, null); Graphics g = pJob.getGraphics(); /* * Print the header with the page-number */ g.setColor(Color.black); g.setFont(new Font(“Arial“, Font.PLAIN , 12)); g.drawString(“page - “ + Integer.toString(intPageCount) + “ -“, 300, 200); /* * Loop to split up the text-stream into single lines; * Extra code for the first line - to catch the case that the text-stream is empty; * then a while-loop for the following lines */ intNewLinePosition = strTextAreaContent.indexOf(„\n“); while (intNewLinePosition >= 0) { /* Text before the 'NewLine' character is split-off */ strLineToBePrinted = strTextAreaContent.substring(0, intNewLinePosition); /* Text after the 'NewLine' character is kept / strTextAreaContent = strTextAreaContent.substring(intNewLinePosition + 1); /* Print the single line in another font; vertical position calculated by the LineCount */ g.setColor(Color.black); g.setFont(new Font(“Courier“, Font.PLAIN , 9)); g.drawString(strLineToBePrinted, 20, 30 + intLineCount*12); /* Increase the LineCount */ intLineCount++; /* Position of the next 'NewLine' character */ intNewLinePosition = strTextAreaContent.indexOf(„\n“); } /* End the printing - this starts the printing on paper */ g.dispose(); pJob.end(); }
To see the effect of the implementation run the program. Please remind to save the code just typed before running the application again by selecting >Run>Run As>Java Application. Do not forget to 'Select Input File' and select the (till now empty) file with the SQL-commands - otherwise the XML-file with the parameters will not be loaded ! Click the button 'Start SQL execution' thereafter to fill the TextArea with content. After clicking the button 'Print the Report' the printer-dialog shows up: Among others, this dialog allows the selection of a printer - if there are more than one installed.
As the SQL-commands in the input-file were only a few till now, the output fitted to one page. To be prepared for a longer list, the printing of more than one page is implemented now. protected static void processPrint(JS_DBLoad parmCallingFrame){ /* * Content of the TextArea on the GUI as a text-stream */ String strTextAreaContent = parmCallingFrame.get_txt_Report().getText(); /* Position of the 'NewLine' character after the first line within the text-stream */ int intNewLinePosition; /* First line within the stream (Text till the 'NewLine' character. * This line will be printed */ String strLineToBePrinted; /* * Variables used for printing the text */ /* Page- and Line-Counter to start a new page and print the page-number on top of the sheet / int intPageCount = 1; int intLineCount = 1; /* Printer-specific variables */ Frame f = new Frame(); PrintJob pJob = f.getToolkit().getPrintJob(f, „JS_DBLoad - Printer Selection“, null); Graphics g = pJob.getGraphics(); /* * Print the header with the page-number */ g.setColor(Color.black); g.setFont(new Font(“Arial“, Font.PLAIN , 12)); g.drawString(“page - “ + Integer.toString(intPageCount) + “ -“, 300, 200); /* * Loop to split up the text-stream into single lines; * Extra code for the first line - to catch the case that the text-stream is empty; * then a while-loop for the following lines */ intNewLinePosition = strTextAreaContent.indexOf(„\n“); while (intNewLinePosition >= 0) { /* Text before the 'NewLine' character is split-off */ strLineToBePrinted = strTextAreaContent.substring(0, intNewLinePosition); /* Text after the 'NewLine' character is kept / strTextAreaContent = strTextAreaContent.substring(intNewLinePosition + 1); /* Print the single line in another font; vertical position calculated by the LineCount */ g.setColor(Color.black); g.setFont(new Font(“Courier“, Font.PLAIN , 9)); g.drawString(strLineToBePrinted, 20, 30 + intLineCount*12); /* Increase the LineCount */ intLineCount++; /* See if the lines overflow page and create new page if necessary */ if (intLineCount > 50) { intLineCount = 1; intPageCount++; /* Dispose the graphic and open a new one; this causes a new page in the PrintJob */ g.dispose(); g = pJob.getGraphics(); /* Print the headline with the page-number (in another font) */ g.setColor(Color.black); g.setFont(new Font(“Arial“, Font.PLAIN , 12)); g.drawString(“page - “ + Integer.toString(intPageCount) + “ -“, 300, 200); } /* Position of the next 'NewLine' character */ intNewLinePosition = strTextAreaContent.indexOf(„\n“); } /* End the printing - this starts the printing on paper */ g.dispose(); pJob.end(); }

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`Print the output in different colors:`

As this step did not grew pretty long, there is some nice little extra implemented: The printed text is colored depending on the kind of information.

The lines to be printed are inspected of the occurence of defined substrings and the color is selected according to the result. protected static void processPrint(JS_DBLoad parmCallingFrame){ /* * Content of the TextArea on the GUI as a text-stream */ String strTextAreaContent = parmCallingFrame.get_txt_Report().getText(); /* Position of the 'NewLine' character after the first line within the text-stream */ int intNewLinePosition; /* First line within the stream (Text till the 'NewLine' character. * This line will be printed */ String strLineToBePrinted; /* * Variables used for printing the text */ /* Page- and Line-Counter to start a new page and print the page-number on top of the sheet / int intPageCount = 1; int intLineCount = 1; /* Printer-specific variables */ Frame f = new Frame(); PrintJob pJob = f.getToolkit().getPrintJob(f, „JS_DBLoad - Printer Selection“, null); Graphics g = pJob.getGraphics(); /* * Print the header with the page-number */ g.setColor(Color.black); g.setFont(new Font(“Arial“, Font.PLAIN , 12)); g.drawString(“page - “ + Integer.toString(intPageCount) + “ -“, 300, 200); /* * Loop to split up the text-stream into single lines; * Extra code for the first line - to catch the case that the text-stream is empty; * then a while-loop for the following lines */ intNewLinePosition = strTextAreaContent.indexOf(„\n“); while (intNewLinePosition >= 0) { /* Text before the 'NewLine' character is split-off */ strLineToBePrinted = strTextAreaContent.substring(0, intNewLinePosition); /* Text after the 'NewLine' character is kept / strTextAreaContent = strTextAreaContent.substring(intNewLinePosition + 1); /* Print the single line in another font; vertical position calculated by the LineCount */ /* Standard color */ g.setColor(Color.black); /* color for the SQL-commands read from the input-file */ if (strLineToBePrinted.compareTo(“input-line:“) >= 0) g.setColor(Color.blue); /* color if the SQL-command was executed */ if (strLineToBePrinted.compareTo(“SQL-command executed“) >= 0) g.setColor(Color.green); /* color if the SQL-command was in error */ if (strLineToBePrinted.compareTo(“SQL-command error“) >= 0) g.setColor(Color.red); g.setFont(new Font(“Courier“, Font.PLAIN , 9)); g.drawString(strLineToBePrinted, 20, 30 + intLineCount*12); /* Increase the LineCount */ intLineCount++; /* See if the lines overflow page and create new page if necessary */ if (intLineCount > 50) { intLineCount = 1; intPageCount++; /* Dispose the graphic and open a new one; this causes a new page in the PrintJob */ g.dispose(); g = pJob.getGraphics(); /* Print the headline with the page-number (in another font) */ g.setColor(Color.black); g.setFont(new Font(“Arial“, Font.PLAIN , 12)); g.drawString(“page - “ + Integer.toString(intPageCount) + “ -“, 300, 200); } /* Position of the next 'NewLine' character */ intNewLinePosition = strTextAreaContent.indexOf(„\n“); } /* End the printing - this starts the printing on paper */ g.dispose(); pJob.end(); }
To see if the code was typed completely error-free, see the final result. Please remind to save the code just typed before running the application by selecting >Run>Run As>Java Application. Do not forget to 'Select Input File' and select the (till now empty) file with the SQL-commands - otherwise the XML-file with the parameters will not be loaded ! Click the button 'Start SQL execution' thereafter ans also print out the result. To save some space the screenshot is skipped.

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`Next Step:`

Pack the project into a JAR (JAva-Archive)-file and run the application out of this file. JS_Base02h, Step 7 - Pack the project into a JAR-file and run it.