Eclipse Error: "Import Cannot Be Resolved"

The imported class is there but Eclipse won't see it.
Try: Project --> Clean

Creating a SVN Repository

Create the repository

> svnadmin create svnrepo

> gedit svnrepo/conf/svnserve.conf

Enable the following lines:

anon-access = none
auth-access = write
password-db = passwd

> gedit svnrepo/conf/passwd

Edit/add user

Create project directory:

> svn -m "Your comment" mkdir file:///data/svnrepo/sample-project
> svn -m "Your comment" mkdir file:///data/svnrepo/sample-project/trunk
> svn -m "Your comment" mkdir file:///data/svnrepo/sample-project/branches
> svn -m "Your comment" mkdir file:///data/svnrepo/sample-project/tags

Import the project:

> svn -m "Your comment" import /path-to-source/sample-project file:///path-to-svnrepo/svnrepo/sample-project/trunk

Prepare work location:

> mkdir sampleProject
> cd sampleProject

Local check out trunk of project (without the folder itself):

> svn co file:///data/svnrepo/sample-project/trunk/ .

Remote check out (using SVN + SSH protocols):

> svn co svn+ssh://user@host/path-to-svnrepo/svnrepo/sample-project/trunk/ .

Create user and group svn:

> useradd svn

Add group svn to your groups.

Change ownership of all files in svnrepo/db to svn:

> chown -r svn:svn *

Add write permissions to all files in svnrepo/db.

Microphone Not Working in Fedora 14

If your microphone is not working on your new installation, just try this. It worked for me:

1. Go to System --> Preferences --> Sound
2. Select the input tab
3. Switch from the existing configured microphone (probably microphone 1) to another one (microphone 2)
4. Close the application and everything should work ;-)

It looks like this issue has been going on and off since Fedora 10...

Spring Property Editor for an Enumeration with Localized Names

Problem statement:

• You use a property editor when you bind a nested Enumeration field of a form backing object.
• You have localized names for the values.

When you write your PropertyEditor you should remember that the getAsText() method needs to take care of the translation:

    @Override
    public String getAsText() {
        
        if(getValue() == null) {
            return null;
        }
        
        SurveyStatus status = (SurveyStatus)getValue();
        return status.getTranslatedName();
    }

while the setAsText() method does not:

    @Override
    public void setAsText(String surveyStatusStr) {
        
        if (logger.isDebugEnabled()) {
            logger.debug("Read string [" + surveyStatusStr + "] for the survey status field");
        }
        
        SurveyStatus status = null;
        
        if (surveyStatusStr.compareTo(SurveyStatus.ACTIVE.toString()) == 0) {
            status = SurveyStatus.ACTIVE;
        }
        else if (surveyStatusStr.compareTo(SurveyStatus.INACTIVE.toString()) == 0) {
            status = SurveyStatus.INACTIVE;
        }

        setValue(status);
    }

This is because Spring implicitly uses the enumeration name for the value of your tag, not the translated name.
E.g. If you have a select tag, this is what Spring does for you:

<option value="ACTIVE" ... >

It makes sense, of course...

Grep Selected Files

You can use find and grep to search for a particular string (string_pattern) in a selection of files:

> find <dir> -name "<file_find_pattern>" -exec grep -H -n '<string_pattern>' {} \;

Spring Open View In Session Pattern For Portlets

I needed to implement the Open Session In View pattern for a portlet using Spring (3 with annotations) and Hibernate.
This pattern allows lazily loaded objects to have access to the Hibernate Session for the entire processing of the render request despite the original transaction (associated to the portlet request) already being completed.
I.e. If you have One To Many associations, this allows you to load the Many side of the association in the same thread of the request where you loaded the One side.

What I needed to do is:
Add a WebRequestHandlerInterceptorAdapter interceptor wrapping the stantard OpenSessionInViewInterceptor to applicationContext.xml:

<bean name="openSessionInViewInterceptor"
   class="org.springframework.web.portlet.handler.WebRequestHandlerInterceptorAdapter">
   <constructor-arg>
       <bean class="org.springframework.orm.hibernate3.support.OpenSessionInViewInterceptor">
           <property name="sessionFactory" ref="sessionFactory"/>
       </bean>
   </constructor-arg>
</bean>

then add it to the DefaultAnnotationHandlerMapping in yourPortlet-portlet.xml:

<bean id="annotationMapper"
   class="org.springframework.web.portlet.mvc.annotation.DefaultAnnotationHandlerMapping">
   <property name="order" value="10" />
   <property name="interceptors">
       <list>
           <ref bean="openSessionInViewInterceptor"/>
       </list>
   </property>
</bean>

Fedora: Receiving Files Over a Bluetooth Connection

This post refers to receiving files from a phone to a computer over a Bluetooth connection.
Please refer to the official Fedora documentation for installation and initial configuration:

• Feature/Bluetooth.
• Documentation/Bluetooth.

Then you have to enable the bluetooth file sharing service.
If you can't find the link to the application in Applications --> System Tools, then create the link yourself or launch the following command manually:
> gnome-file-share-properties&

Enable Receive Files over Bluetooth.
Go to your phone and send the file to your computer.

Hibernate ManyToOne Association With Annotations

It took me a while to get rid of a:
ERROR org.hibernate.util.JDBCExceptionReporter -
Unknown column 'applicatio0_.domain_domainID' in 'field list'

on a simple many-to-one association.
I had an Application object with a Domain field where many Applications could have the same Domain (standard many-to-one association).
The annotations on the field were:

@ManyToOne(cascade = CascadeType.ALL)
public Domain getDomain() {
    return domain;
}

Class Domain started with:

@Entity
@Table(name="domain")
public class Domain implements Serializable {
// DB name: domainID
private Long id;
private String name;

Hibernate couldn't correctly map the domain ID until I added the JoinColumn annotation:

@ManyToOne(cascade = CascadeType.ALL)
@JoinColumn(name="domainID")
public Domain getDomain() {
    return domain;
}

which in my opinion could be inferred from class Domain:

@Id
@GeneratedValue(strategy=GenerationType.AUTO)
@Column(name = "domainID", unique = true,
        updatable = false, nullable = false)
public Long getId() {
    return this.id;
}

but it wasn't.
Always use JoinColumn.

Creating a Movie from Images (Linux)

The short story at this time. These instructions refer to the creation of MPEG4 video from JPGs images on Linux.
You need mencoder, part of the mplayer software.

Type:

> mencoder mf://<PATH>/*.jpg -mf w=320:h=240:fps=12:type=jpg
-ovc lavc -lavcopts vcodec=mpeg4:mbd=2:trell
-oac copy -o output.avi

Where you should customize at least:

• <PATH>/*.jpg is the path to the directory where your JPGs are.
• w=320:h=240 is the image size.
• output.avi is the resulting file name

Eclipse: Copying Preferences To a New Workspace

When I create a new workspace in Eclipse what I want every time is to have all my preferences from the other workspaces, first of all the color preferences. There is no apparent option in Eclipse to do that. File --> Import --> Preferences won't do that. Maybe it's hidden somewhere else.
I found an easy way to do that: simply copy the settings directory to the new workspace.
Preferences are stored in each workspace in:
/.metadata/.plugins/org.eclipse.core.runtime/.settings

Shut down Eclipse.
Copy part or the entire contents of that directory to the corresponding directory of the new workspace (after you've created it, of course).
Restart and you're done!

Turning a SVN Project into a SVN/Java Project

This will be needed for a Java project created with the type "from SVN source". It will not have a Java nature by default.

Add a Java nature to the project in .project:

 <natures>
     <nature>org.eclipse.jdt.core.javanature</nature>
 </natures>

Create the file .classpath with the JDK/JRE libraries (and optionally the default output directory):

 <?xml version="1.0" encoding="UTF-8"?>
 <classpath>
    <classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
    <classpathentry kind="output" path="bin"/>
 </classpath>

Then you might want to add to the classpath the libraries which could not be detected at creation time.

This method is alternative to the one detailed here.

Eclipse: Hiding Internal JARs

If you need to hide all the internal libraries your project is using, you can do so from the Package Explorer:

1. Choose the view menu
2. Check Show referenced libraries node

You can't do that from the Project Explorer (formerly Resource Navigator) since that is a view not reserved to Java projects.