The syntax is a [...]]]> JDK 7 has several enhancements to the try-catch construct. Try with resources allows for ensuring that resources are closed and freed up without the need to explicitly call the close function. Any class implementing java.lang.AutoCloseable can be automatically closed without the need for a finally section in the try block.

The syntax is a try with parens and the resources to automatically close out inside the parens.
try ( resources ) { code } catch (exception) { }

snippet 1 shows the syntax for try with resources:

try (
    BufferedReader reader = new BufferedReader(
        new FileReader("c:/dev/jdk7test/t1.ofx"));
   BufferedWriter writer = new BufferedWriter(
        new FileWriter("c:/dev/jdk7test/output.txt"))
   ) {
         // read and write
     }

Another change to try is that the catch can now handle multiple exception types in one block. Multiple catch blocks are optional and still work fine if you prefer to separate the handling. Just separate the exception types with | .

Snippet 2 catch with multiple exception types:

catch (java.io.FileNotFoundException | java.io.IOException ex) {
    System.out.println(ex.getMessage());
}

Lastly here is a small simple class that shows both features in action.

package jdk7test;
import java.io.*;
public class Jdk7TryWithResourcesTest {
    public static void main(String[] args) {
        Jdk7TryWithResourcesTest test = new Jdk7TryWithResourcesTest();
        test.execute();
    }

    public void execute() {
        try (
                BufferedReader reader = new BufferedReader(new FileReader("c:/dev/jdk7test/t1.ofx"));
                BufferedWriter writer = new BufferedWriter(new FileWriter("c:/dev/jdk7test/output.txt"))
            ) {
            String line;
            while ((line = reader.readLine()) != null){
                writer.write(line);
            }
        } catch (java.io.FileNotFoundException | java.io.IOException ex) {
            System.out.println(ex.getMessage());
        }
    }
}

At the bottom of this post is a small [...]]]> JDK 7 adds the ability to use String objects as the case in switch blocks. It’s not exactly an earth shattering addition but I find it quite useful in avoiding long if-then chains. Plus the release docs claim that using a switch is more efficient.

At the bottom of this post is a small java class that provides a complete example of use. Here is the part we’re concerned about. The switch takes a String argument that should be the abbreviated name of a month and sets the return value to the quarter of the year that month is in.

switch(monthIn) {
            case "Jan":
            case "Feb":
            case "Mar":
                retval = "Q1";
                break;
            case "Apr":
            case "May":
            case "Jun":
                retval = "Q2";
                break;
            case "Jul":
            case "Aug":
            case "Sep":
                retval = "Q3";
                break;
            case "Oct":
            case "Nov":
            case "Dec":
                retval = "Q4";
                break;
            default:
                throw new IllegalArgumentException("Invalid Month argument: " + monthIn);
}

That’s a pretty geedunk example but it shows the functionality and is simple to read/understand. Here is a complete class that shows the same switch statement in use:

package jdk7test;
import java.util.Calendar;

public class Jdk7test {
    public static void main(String args[]) {
        Jdk7test test = new Jdk7test();
        test.execute();
    }

    public void execute() {
        String[] strMonths = new String[] { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug",
                                            "Sep", "Oct", "Nov", "Dec" };
        Calendar cal = Calendar.getInstance();
        try {
            String monthName = strMonths[cal.get(Calendar.MONTH)];
            String quarter = getQuarter(monthName);
            System.out.println("Month: " +  monthName + " is in quarter: "
                               + quarter);
        } catch (IllegalArgumentException e) {
            System.out.println("The month sent to getQuarter was invalid");
            System.out.println(e.getMessage());
        }
    }

    public String getQuarter(String monthIn) {
        String retval;
        switch(monthIn) {
            case "Jan":
            case "Feb":
            case "Mar":
                retval = "Q1";
                break;
            case "Apr":
            case "May":
            case "Jun":
                retval = "Q2";
                break;
            case "Jul":
            case "Aug":
            case "Sep":
                retval = "Q3";
                break;
            case "Oct":
            case "Nov":
            case "Dec":
                retval = "Q4";
                break;
            default:
                throw new IllegalArgumentException("Invalid Month argument: " + monthIn);
        }
        return retval;
    }
}

As I test out the release I’ll do some posts on [...]]]> Build 147 for JDK 7 is now available with the goal of a generally available release later this month. Some good resources are:

• Oracle’s Java 7 wiki
• Java 7 project page
• Get the release from the download page
• Oracle’s Java SE 7 documentation

As I test out the release I’ll do some posts on new features.

Java, Java 7, JDK 7, Roger Cuddy

In practice it’s very much the same as use with hashes. each still returns 2 results with the first one being [...]]]> As of version 5.12 perl now supports using each with arrays and hashes both. For our pm project we should get in habit of using it. No need to rewrite any old code.

In practice it’s very much the same as use with hashes. each still returns 2 results with the first one being the index in the array instead of the key for a hash. This lets us use the convenience of a while loop to step through the array getting both the index and value.

Short simple example:

my @arr = qw(test1 test2 test3 test4);
while (my ($idx, $val) = each @arr) {
	print($idx, $val);
};

gives output:

0, test1
1, test2
2, test3
3, test4

The iterator here will respond to changes in the array inside the while block. I really don’t recommend changing inside the loop but just as an example:

my @arr = qw(test1 test2 test3 test4);
while (my ($idx, $val) = each @arr) {
  if ($idx == 3) {
    push @arr,"test5";
  }
  print("$idx, $val\n");
};

will output:

0, test1
1, test2
2, test3
3, test4
4, test5

Poor and I have tried to structure the build process to minimize special requirements on any [...]]]> We’re still a bit undecided on whether to use the library website to post items intended only to the dev team. For now dev items will be posted on my SourceForge site and at Poor’s site both.

Poor and I have tried to structure the build process to minimize special requirements on any developer’s machine . So far at least we’ve been able to keep it pretty mild, especially if you only have the developer role. Most developers will already have everything they need installed.

To develop and build

• Text Editor of your choice. Use whichever tool you normally do but DO NOT check IDE specific files into the source repository.
• Subversion (and a GUI if you wish)
• JDK 1.6 SE
• Ant 1.7.1
• Optional – PMD installed for use by Ant, ant task doc

If you will be working on the website then you need to add a little more

• Pushing to the website via the build script requires that your ssh key be registered with sourceforge. We very much do not want any user ids and passwords embedded in the script at any time. It’s just too easy  to forget and check in build.xml with your id / pw now publicly available.
• Pushing from Ant requires you have optional library JSch installed.

That’s it for now anyway. Changes will be posted as new articles so they are easy to catch.

<edit>The install went well. You can read about it at the follow up post [...]]]> Can you really run a functioning WordPress blog on Source Forge’s user space? We’re going to find out. My first thought about installing was admittedly ‘this is going to hurt!’. Once setup it will be accessible at Rog’s SF Notes

<edit>The install went well. You can read about it at the follow up post <end edit>

Goals:

1. Be able to install themes and plugins.
2. Responsive enough that it drives readers mad waiting on pages to render.
3. Support sitemaps
4. Easy to backup/restore both the database and the file system.
5. Allow multiple contributors

Quite modest but if I can get that much working I’ll be pretty happy. #1 itself rules out using SF’s Hosted Apps as it won’t be possible to use any themes or plugins.

Will post soon on how it all went.