Java

Sometimes QR codes are a nice way to distribute information like calendar events, contact information, e-mail, geo-locations or internet addresses. In the following article we’re going to encode information to QR code images using the ZXing library and afterwards decode information from a given QR code. Finally we’re taking a look on online QR code generators and how to integrate the ZXing library in a Maven project. The ZXing Library Download the ZXing Libraries from http://code.google.com/p/zxing/downloads/list – the file name is ZXing-<version>.zip Unpack the downloaded archive somewhere Change to the extracted directory and run ant. If you don’t have JavaME installed – and you don’t have to for the samples below – run ant buildwithoutj2me – that will do the job Having compiled the libraries you’re now free to include the core.jar from zxing-<version>/core/ and the javase.jar from zxing-<version>/javase as dependency in your project ...

Sometimes one needs to look up license details of a running Confluence system .. perhaps for creating a commercial plugin or to display recommendations dependant from the license used. For this reason there are a few possibilities for receiving some license information from the Confluence API or the velocity context. Note: This article is outdated since the Atlassian Marketplace was launched and a shiny new licensing API was added. Until this article is updated I strongly recommend to take a closer look at the detailed information that Atlassian is providing in the Developer Documentation. ...

Sound recording and playback is really simple using the MediaRecorder and MediaPlayer classes .. see the example below .. Sample App First some layout .. a button to start/stop recording and a button to play the recorded stuff (main.xml): <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <TextView android:id="@+id/output" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="" /> <Button android:text="@+string/record" android:id="@+id/btRecord" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button> <Button android:text="@+string/play" android:id="@+id/btPlay" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button> </LinearLayout> Adjusting the externalized strings in the strings.xml <?xml version="1.0" encoding="utf-8"?> <resources> <string name="app_name">Soundrecorder Tutorial</string> <string name="record">Record!</string> <string name="play">Play</string> </resources> ...

Here is an example on how to use the accelerometer in your Android application. If you want to simulate the acceleration on the emulator I highly recommend the Sensor Simulator on the OpenIntents website. The following example app displays the coordinates received by the sensor. The Acceleration App The activity – AccelerationActivity.java package com.hascode.android; import android.app.Activity; import android.content.Context; import android.hardware.Sensor; import android.hardware.SensorEvent; import android.hardware.SensorEventListener; import android.hardware.SensorManager; import android.os.Bundle; import android.widget.TextView; public class AccellerationActivity extends Activity { private TextView result; private SensorManager sensorManager; private Sensor sensor; private float x, y, z; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE); sensor = sensorManager.getSensorList(Sensor.TYPE_ACCELEROMETER).get(0); result = (TextView) findViewById(R.id.result); result.setText("No result yet"); } private void refreshDisplay() { String output = String .format("x is: %f / y is: %f / z is: %f", x, y, z); result.setText(output); } @Override protected void onResume() { super.onResume(); sensorManager.registerListener(accelerationListener, sensor, SensorManager.SENSOR_DELAY_GAME); } @Override protected void onStop() { sensorManager.unregisterListener(accelerationListener); super.onStop(); } private SensorEventListener accelerationListener = new SensorEventListener() { @Override public void onAccuracyChanged(Sensor sensor, int acc) { } @Override public void onSensorChanged(SensorEvent event) { x = event.values[0]; y = event.values[1]; z = event.values[2]; refreshDisplay(); } }; } ...

In this tutorial we are going to build a simple todo app that is able to store simple todos in a database. The user is able to add new todos or delete old ones by clicking on a todo. For this tutorial we won’t use maven to keep it simple – if maven integration is desired – take a look at this tutorial. Steps Create a new android project using the Android SDK and your IDE Create some packages com.hascode.android.activity and com.hascode.android.persistence Create the layout in res/layout/main.xml – the main elements: a listview for the todos-list, a textbox and a button to enter new data. <?xml version="1.0" encoding="utf-8"?> <RelativeLayout android:id="@+id/widget31" android:layout_width="fill_parent" android:layout_height="fill_parent" xmlns:android="http://schemas.android.com/apk/res/android" > <TableRow android:id="@+id/row" android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:layout_below="@+id/tasklist" android:layout_alignParentLeft="true" > <EditText android:id="@+id/etNewTask" android:layout_width="200px" android:layout_height="wrap_content" android:text="" android:textSize="18sp" > </EditText> <Button android:id="@+id/btNewTask" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@+string/add_button_name" > </Button> </TableRow> <ListView android:id="@+id/tasklist" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:layout_alignParentLeft="true" > </ListView> </RelativeLayout> ...

Searching for nice coding kata sites I found this one – codingkata.org – I really liked because of the quick start and nice maven integration. Just head over to the kata overview select the kata you wish to try out, copy the generated maven command line option and run it in the console – heres the code for the hello-world sample: Coding Katas from Maven Archetype mvn archetype:generate -DinteractiveMode=false -DarchetypeRepository=http://www.codingkata.org/repo/release -DarchetypeGroupId=org.codingkata.template -DarchetypeArtifactId=solv-java-archetype -DarchetypeVersion=1.04 -DgroupId=org.codingkata.unit -DartifactId=hello-world-solv-java -DkataId=hello-world -DkataVersion=1.02 -DlangVersion=1.6 -DlibVersion=1.3.2 -Dversion=1271358 ...

The goal is to build a small macro plugin deployable via the Confluence plugin API rendering some spaces. Please note that I am going to build the plugin using just Maven and not the Atlassian Maven Wrapper called the “Atlassian Plugin SDK” – more information about that is available at the Atlassian website. The macro output will be rendered using a Velocity template and all messages are stored for i18n in properties files bundled with the plugin. ...

Having written the article “How to build a Confluence SOAP client in 5 minutes” some readers asked me for some more information and help using the JAX-WS plugin that I mentioned in the article instead of the Axis plugin – so here we go ;)[more-367]# Steps Create a simple maven project first using archetype:create or archetype:generate mvn archetype:create -DgroupId=com.hascode.jaxws -DartifactId=soap-tutorial We get a pom.xml like this: <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.hascode.jaxws</groupId> <artifactId>soap-tutorial</artifactId> <version>0.1</version> </project> ...

In a maven project there are lots of dependencies to handle – often one wants to know which version of a software comes from. The solution to this problem is the Maven Dependency Plugin which helps you to find used/unused/declared/undeclared dependencies in your project. In addition the plugin allows you to copy or unpack artifacts. Maven Goals dependency:copy – copies artifacts defined in the config to a specified location – details available here dependency:resolve – resolves all dependencies and shows the versions dependency:go-offline – resolves everything the project needs like dependencies, plugins and reports dependency:analyze - parses the dependencies and shows if they are used/declared/unused/undeclared .. dependency:analyze-dep-gmt - finds mismatches between resolved dependencies and those listed in the dependencyManagement section dependency:tree – shows a nice dependency tree for the maven project ...

Building a simple IMAP Client that displays the subject of the messages in the “inbox” Folder using Maven (I just like Maven). Project Setup / Maven Create a new Maven project mvn archetype:create -DgroupId=com.hascode.imap -DartifactId=imap-client Edit your pom.xml and add some dependencies <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.hascode.imap</groupId> <artifactId>imap-client</artifactId> <version>0.0.1-SNAPSHOT</version> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.8.1</version> </dependency> <dependency> <groupId>javax.mail</groupId> <artifactId>mail</artifactId> <version>1.4.2</version> </dependency> </dependencies> </project> Creating the E-Mail Client Create a package .. something like com.hascode.imap.client ;) Create a simple mail client using javax.mail in a class named ImapClient package com.hascode.imap.client; import javax.mail.Folder; import javax.mail.Message; import javax.mail.MessagingException; import javax.mail.Session; import javax.mail.Store; public class ImapClient { private Session session = null; private Store store = null; private String host = null; private String userName = null; private String password = null; public ImapClient(String host, String userName, String password){ this.host = host; this.userName = userName; this.password = password; } public boolean getMail() throws MessagingException { session = Session.getDefaultInstance(System.getProperties(),null); // session.setDebug(true); System.out.println("get store.."); store = session.getStore("imaps"); System.out.println("connect.."); store.connect(this.host, this.userName, this.password); System.out.println("get default folder .."); Folder folder = store.getDefaultFolder(); folder = folder.getFolder("inbox"); folder.open(Folder.READ_ONLY); System.out.println("reading messages.."); Message[] messages = folder.getMessages(); for(Message m:messages){ System.out.println(m.getSubject()); } return false; } } ...