Code Samples

Thursday, December 13, 2012

Java: iterate through HashMap

Map resultMap = new HashMap();

ResultSet resultSetRegion = s.executeQuery(sSql2);
if(resultSetRegion.next()) {
    resultMap.put( "firstName", "" + resultSetRegion.getString("first_name") );
}

Iterator it = resultMap.entrySet().iterator();
while (it.hasNext()) {
    Map.Entry pairs = (Map.Entry) it.next();
    System.out.println("KEY: "+pairs.getKey()+"\tVALUE: "+pairs.getValue());
}

Run Bash Script Using Java And Get Debug And Error Output

String command = "sudo /usr/bin/some_name.sh";
System.out.println("runBashScriptCommand: " + command);
try {
    Runtime runtime = Runtime.getRuntime();
    Process process = runtime.exec(command);
    printBufferedReaderOutputFromProcess(process);
    process.waitFor();
    return "true";
} catch (Exception ex) {
    System.out.println("EX:" + ex.toString());
    return ex.toString();
}

private void printBufferedReaderOutputFromProcess(Process p) {
    try {
        String s = null;
        BufferedReader stdInput = new BufferedReader(new InputStreamReader(p.getInputStream()));
        BufferedReader stdError = new BufferedReader(new InputStreamReader(p.getErrorStream()));
        // read the output from the command
        System.out.println("\n\npHere is the standard output of the command:\n");
        while ((s = stdInput.readLine()) != null) {
            System.out.println(s);
        }
        // read any errors from the attempted command
        System.out.println("Here is the standard error of the command (if any):\n");
        while ((s = stdError.readLine()) != null) {
            System.out.println(s);
        }
    } catch (Exception ex) {
        System.out.println("printBufferedReaderOutputFromProcess:" + ex.toString());
    }
}

Wednesday, December 12, 2012

Height of tab (JTabbedPane) in MAC

Code:

JTabbedPane paneItem = new JTabbedPane();
JLabel iconInTab = new JLabel(new ImageIcon("myImage.png"));
iconInTab.setPreferredSize(new Dimension(100,80)); 
paneItem.addTab(null,new JPanel());
paneItem.setTabComponentAt(0,iconInTab);

I've also try this using html but it did not work either:
paneItem.addTab("<html><p><p><p></html>",new ImageIcon("myImage.png"),new JPanel())

Solution:
paneItem.setUI(new BasicTabbedPaneUI());

Also with some features:
paneItem.setTabPlacement(JTabbedPane.TOP);
paneItem.setTabLayoutPolicy(JTabbedPane.WRAP_TAB_LAYOUT);
paneItem.setComponentOrientation(ComponentOrientation.LEFT_TO_RIGHT);

Tuesday, December 11, 2012

Move all files except one

File Structure:
/root/tmp/test
[root@dswing test]# ll
total 12
-rw-r--r-- 1 root root    2 Dec 12 13:41 a.txt
-rw-r--r-- 1 root root    4 Dec 12 13:42 b.txt
-rw-r--r-- 1 root root    0 Dec 12 13:43 c.txt
drwxr-xr-x 2 root root 4096 Dec 12 13:50 ks

Command:
find /root/tmp/test/ -maxdepth 1 -mindepth 1 -type f -not -name c.txt | grep -i txt$ | xargs -i cp -af {} /root/tmp/test/ks

Description:

-maxdepth 1 makes it not search recursively.

-mindepth 1 makes it not include the /root/tmp/test/ path itself into the result.

-type f means search only for file type.

-not -name c.txt means all files except c.txt

grep -i txt$ means files name ends with txt.

Put a.txt -file to the end of b.txt -file

In a bash script such append.sh file, write the following code:

#!/bin/bash
A=/root/tmp/test/a.txt
B=/root/tmp/test/b.txt
cat $A >> $B

The >> redirects the output of the cat command (which output file A) to the file B. But instead of overwriting contents of B, it appends to it. If you use a single >, it will instead overwrite any previous content in B.

Check if a program exists from a bash script

$ command -v foo >/dev/null 2>&1 || {

  echo >&2 "I require foo but it's not installed.  Aborting."; exit 1;

OR 
$ type foo >/dev/null 2>&1 || {

  echo >&2 "I require foo but it's not installed.  Aborting."; exit 1;

OR 
$ hash foo 2>/dev/null || {

  echo >&2 "I require foo but it's not installed.  Aborting."; exit 1;

Resize a list of images in line command

for file in *.jpg; do

  convert -resize 800x600 -- "$file" "${file%%.jpg}-resized.jpg";

done

OR

ls *.jpg|sed -e 's/\..*//'|xargs -I X convert X.jpg whatever-options X-resized.jpg

# .jpg files, 10% size, no rename, it will overwrite the old pictures
#!/bin/bash
for i in *.jpg; do convert $i -resize 10% $(basename $i .jpg).jpg; done

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