computing tales

Singleton pattern

2021-06-01T10:14:00.003+02:00

Well I was looking for information about the singleton pattern in Java. The singleton pattern is used for classes which can have only one instance.

Let's follow the logic, we want one class to have only one object, the object is being created by the constructor, so I want to control when constructor is being called, the easiest way is to be me the only one that can call the constructor, so making the constructor private seems a good step. Once I have the instance then I have to give the possibility to get this instance by creating a getter.

But If I do not have the instance yet I cannot access the instance methods but only the static methods, so we can access them from the class.

public class MySingleton{

private static MySingleton instance=new MySingleton();

private MySingleton(){};

public static MySingleton getInstance(){

return instance;

}

Keep the constructor private
initialize instance field with the private constructor
create a getter to get the instance

But this implementation leads to the possibility to create more instances of MySingleton by extending the class, If I create a subclass of MySingleton for example MyMiniSingleton, then MyMiniSingleton is an instance also of MySingleton.

for more information: http://java.sun.com/developer/technicalArticles/Programming/singletons/

How to install axis2 and (auto) create a simple example

2012-05-23T09:18:00.001+02:00

The Sencide Blog: Create Web Service in Java Using Apache Axis2 and ...: Web services are application components which communicate using open protocols. Using Web Services we can publish our application's function...

New version of MultiLektor (now only polish version available of the new update)

2012-04-17T22:01:00.000+02:00

I have found some bugs around the last version of MultiLektor, I updated the polish version (the other versions will be updated during the next days).

Before the chapters where not modified when closing, or changing the chapter, now that bug is fixed.

download new version (in polish) (problem solved with the link)

Moreover, I want to inform that I am working in new functionalities, some of them are:
- show the list of words in a chapter
- modify the stored words
- and I am working to add verbs and conjugations....

Please, inform me if you find some problem/bug when using Multilektor. Also I would like to know which funcionalities you would like to have.

Thanks you :P!

You can also send me your dictionary files (remember that actually you can use the same files with PersonalDictionary!)

version 3 of personalDictionary!

2012-04-15T20:47:00.000+02:00

New version of PersonalDictionary, as promised with import/export function by using the SD Card.
What is new is that you can use with MultiLektor! you only have to copy the file exported by PersonalDictionary to the chapters directory of MultiLektor.

For export you have to go to the copy function, insert a name of the file and press Store, you will find this file inside the sd card in the folder of the app, the folder is named personalDictionary.

For import you have to insert the file inside the same folder and later, import by using the copy function again, but now inserting the name of the file (by hand) and pressing to export.

What you can do with MultiLektor is add new words some functions will be added during the next days (as modify, list, delete...)

Use PersonalDictionary to have access to your personal pocket dictionary where you can store as much words as you want with your own translation and access wherever you want. Now, moreover you can train and learn this words by using MultiLektor.

Still some functions are not developed but you can always open the dictionary files with any text reader for example notepad and modify the words, only try to follow the pattern:

original word=translated word
original word2=translated word2

you can insert sentences also!!!

market android (play)

New version available of PersonalDictionary

2012-02-19T16:42:00.002+01:00

A new version of PersonalDictionary is now available at the android market, still free version. With a new interface and new functions, export and import files.

Exporting and importing files make easier to share your dictionary with your friends, It uses an easy structure, It should contain the list of words as:

lang_a lang_b

The word in the translated language and the original are delimited by a tab character (/t) and one pair of words from another by a new line character (/n).

Now the main options are delimited (still you can create words when searching) in Search, Add and Copy.

Search is used for search and consult the words that our dictionary contains, with the possibility to modify/delete one of them by selecting It. Moreover, there you can add new words by writting the translated word and clicking on the "add" button.

Add is used for add new words, where you can add the original word and the translated word.

You can find more information about PersonalDictionary and download It in the android market

MultiLektor new version!

2012-02-09T19:06:00.001+01:00

Now there are new available versions for download of MultiLektor, you can choose between spanish, polish and english version. Moreover with some changes and solved bugs. If you find some errors or have other inquires or advices please contact with me.

*If you have an old version of MultiLektor, copy your chapters folder to the new version folder.

Use MultiLektor for learning languages, in special vocabulary.

MultiLektor is free and portable, do not need installation, only unpacking.

MultiLektor is a personal teacher, you can add your own words and your own translations and after adding these words It will tests you.

For a better usability you can create chapters, and inside the chapters you add words, the words, its translation and chapters are from your own election. MultiLektor is one of the most flexible vocabulary trainers that I know.

The MultiLektor characteristics:

- add new chapters

-add new words*

-run a normal exercise*

-run an extra exercise*

*(needs to have selected a chapter)

The main window has at left the different options to select, at the beginning, only 2 options are available "Add new chapter" and "Select Chapter".

When the option "Select chapter" is activated, the created chapters are listed.

When a chapter is selected automatically the normal exercise begins showing the first word of the selected chapter, some information displays are shown, errors, actual (the actual word number), total (the number that the actual chapter contains).

The normal exercise consists on writing the translation of the shown word, the shown word is after the tag "translate".

If you fail at 1st try, the display bledy is updated with the new failed word, at the 2nd try you have some help, making easier to guess the correct answer.

*the bledy (errors) counts the stored errors, It could not begin by 0.

When the normal exercise is finished, this occurs when you arrive to the last word, you can access to "Extra exercise", where you will train the committed errors during the "Exercise". It works as the "Exercise", but also has a new functionality, the words answered correctly at first try will decrease the "failed" display and will be marked as correct.

If you create new chapters and you want to share with the rest, please send me a mail to victormr88@gmail.com with the subject "MultiLektor: new chapter" and the chapter you have created (you will find inside the "chapters" folder).

MultiLektor polish version
MultiLektor spanish version
MultiLektor english version

chapters:
German-spanish: jobs
English-spanish: c1 words text
Polish-spanish: kitchen
Polish-spanish: time
Polish-spanish: health
*for use this chapters you have to download and copy inside the chapters folder (inside the MultiLektor folder)

UPDATED AGAIN with solved problems with the extra exercise option.

MultiLektor

2012-02-09T00:52:00.002+01:00

Use MultiLektor for learning languages, in special vocabulary. Recently It is available only in polish but other language versions will be available during the next days.

Please note that It is a beta version, still in test process, If you find some errors or have other inquires or advices please contact with me.

MultiLektor is free and portable, do not need installation, only unpacking.

MultiLektor is a personal teacher, you can add your own words and your own translations and after adding these words It will tests you.

The MultiLektor characteristics:

- add new chapters

-add new words*

-run a normal exercise*

-run an extra exercise*

*(needs to have selected a chapter)

The main window has at left the different options to select, at the beginning, only 2 options are available "Dodaj nowe temat" (add new chapter) and "Zmien temat" (select chapter).

When the option "Zmien Temat" (change chapter) is activated, the created chapters are listed.

When a chapter is selected automatically the normal exercise begins showing the first word of the selected chapter, some information displays are shown, bledy (errors), numer(number, the actual word number), wszystkie (the number that the actual chapter contains).

The normal exercise consists on writing the translation of the shown word, the shown word is after the tag "tlumacz" (translate).

If you fail at 1st try, the display bledy is updated with the new failed word, at the 2nd try you have some help, making easier to guess the correct answer.

*the bledy (errors) counts the stored errors, It could not begin by 0.
When the normal exercise is finished, this occurs when you arrive to the last word, you can access to "Cwiczenia dodatkowa" (extra exercise), where you will train the committed errors during the "Cwiczenia" (normal exercise).

It works as the "Cwiczenia", but also has a new functionality, the words answered correctly at first try will decrease the "bledy" (errors) display and will be marked as correct.

If you create new chapters and you want to share with the rest, please send me a mail to victormr88@gmail.com with the subject "MultiLektor: new chapter" and the chapter you have created (you will find inside the "chapters" folder).

THERE IS A NEW VERSION AND NEW PHOTOS IN http://computing-tales.blogspot.com/2012/02/multilektor-new-version.html
*for use this chapters you have to download and copy inside the chapters folder (inside the MultiLektor folder)

Android: Personal Dictionary App

2012-01-29T19:53:00.000+01:00

It helps you to create your own dictionary.
So at the beginning you have to add words and its translations, and after that, you can consult the stored words, modify or delete (selecting the word).
I think that It is very helpful when arriving to a new country, or when learning new languages because you can store for example the ingredients at the beginning, and when going to a restaurant you can consult the meaning really quickly.

it's free!

When learning a new language, one of the most important things is the vocabulary.

It is important to have a tool where write new words to learn. A place where you can consult and modify, when needed.

My Personal Dictionary is the tool that will help you when learning new languages.

With Personal Dictionary you can:
Add new words
Search stored words
Modify stored words
Delete stored words

https://market.android.com/details?id=personalDictionary.vmrvictor

Android: creating and fullfilling a list

2012-01-29T19:28:00.000+01:00

Sometimes, It is needed to update a list of elements, for example for an agenda, a list of things to buy, etc.

For create a list we have to add to our xml layout the following:

<ListView
android:id="@android:id/list"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
</ListView>

and we can add entries by using code, for example the action fillData(), will take our own objects, in my case words and add them to the list by using an adapter.

private void fillData() {
//db.open(); open the database
words = db.fetchAllWords();
ArrayAdapter<Word> adapter= new ArrayAdapter<Word>(this, R.layout.entry, R.id.text1, words);
ListView lv = getListView();
lv.setAdapter(adapter);
//db.close();
}

your own objects, in my case Word needs to have overriten the toString method, the string that will be returned is the string used by the adapter, so the string which will be used for fullfill the list.

@Override
public String toString(){
return a+" -> "+b;
}

Android: Updating values when returning from another activity

2012-01-29T15:48:00.000+01:00

The problem that I had was that when returning from an activity the list was not getting update until a keyEvent was realized.

For example, the main activity contain a list of strings that gets from a database, It is updated by using the action FillData(), and I had an activity for add new elements to the database, and another for modify or delete.

The problem was that when creating/adding/modifying the values at one of the other activities and finishing this activies (returning to the main activity) the list was not updated with the new values.

The solution of this problem is to Overrite the onResume() event, looking at the graph of http://developer.android.com/reference/android/app/Activity.html that when the event is Paused, later on is called the onResume event.

For example in my case:

@Override
public void onResume(){
super.onResume();
EditText searchTextField=(EditText) findViewById(R.id.searchTextField);
fillData(searchTextField.getText());
}

I get the value from an EditText field getting the filter to use when filling the list and later call to fillData that fullfills the list.

from 0

2011-07-12T09:30:00.000+02:00

Start developing my first blog about computer