Useful Eclipse Java Code Templates

Question

You can create various Java code templates in Eclipse via the

Window->Preferences->Java -> Editor -> Templates

e.g.

sysout is expanded to:

System.out.println(${word_selection}${});${cursor}

You can activate this by typing sysout followed by CTRL+SPACE

What useful Java code templates do you currently use?
Include the name and description of it and why it's awesome.

There's an open bounty on this for an original/novel use of a template rather than a built-in existing feature.

• Create Log4J logger
• Get swt color from display
• Syncexec - Eclipse Framework
• Singleton Pattern/Enum Singleton Generation
• Readfile
• Const
• Traceout
• Format String
• Comment Code Review
• String format
• Try Finally Lock
• Message Format i18n and log
• Equalsbuilder
• Hashcodebuilder
• Spring Object Injection
• Create FileOutputStream

Answer 1

For log, a helpful little ditty to add in the member variable.

private static Log log = LogFactory.getLog(${enclosing_type}.class);

Answer 2

One of my beloved is foreach:

for (${iterable_type} ${iterable_element} : ${iterable}) {
    ${cursor}
}

And traceout, since I'm using it a lot for tracking:

System.out.println("${enclosing_type}.${enclosing_method}()");

Just thought about another one, have found it over Internet some day const:

private static final ${type} ${name} = new ${type} ${cursor};

Answer 3

Create Log4J logger:

${:import(org.apache.log4j.Logger)}
private static final Logger _logger = Logger.getLogger(${enclosing_type}.class);

It both creates the Logger with a proper category and imports it.

Source.

Answer 4

Get an SWT color from current display:

Display.getCurrent().getSystemColor(SWT.COLOR_${cursor})

Suround with syncexec

PlatformUI.getWorkbench().getDisplay().syncExec(new Runnable(){
    public void run(){
     ${line_selection}${cursor}
    }
});

Use the singleton design pattern:

/**
 * The shared instance.
 */
private static ${enclosing_type} instance = new ${enclosing_type}();

/**
 * Private constructor.
 */
private ${enclosing_type}() {
    super();
}

/**
 * Returns this shared instance.
 *
 * @returns The shared instance
 */
public static ${enclosing_type} getInstance() {
    return instance;
}

Answer 5

Some additional templates here:

http://fahdshariff.blogspot.com/2008/11/eclipse-code-templates.html

I like this one:

readfile

 ${:import(java.io.BufferedReader,  
           java.io.FileNotFoundException,  
           java.io.FileReader,  
           java.io.IOException)}  
 BufferedReader in = null;  
 try {  
    in = new BufferedReader(new FileReader(${fileName}));  
    String line;  
    while ((line = in.readLine()) != null) {  
       ${process}  
    }  
 }  
 catch (FileNotFoundException e) {  
    logger.error(e) ;  
 }  
 catch (IOException e) {  
    logger.error(e) ;  
 } finally {  
    if(in != null) in.close();  
 }  
 ${cursor}

Answer 6

Nothing fancy for code production - but quite useful for code reviews

I have my template coderev low/med/high do the following

/**
 * Code Review: Low Importance
 * 
 *
 * TODO: Insert problem with code here 
 *
 */

And then in the Tasks view - will show me all of the code review comments I want to bring up during a meeting.

Answer 7

I like a generated class comment like this:

/**
 * I... 
 * 
 * $Id$
 */

The "I..." immediately encourages the developer to describe what the class does. I does seem to improve the problem of undocumented classes.

And of course the $Id$ is a useful CVS keyword.

Answer 8

I use this for MessageFormat (using Java 1.4). That way I am sure that I have no concatenations that are hard to extract when doing internationalization

i18n

String msg = "${message}";
Object[] params = {${params}};
MessageFormat.format(msg, params);

Also for logging:

log

if(logger.isDebugEnabled()){
  String msg = "${message}"; //NLS-1
  Object[] params = {${params}};
  logger.debug(MessageFormat.format(msg, params));
}

Answer 9

strf -> String.format("msg", args) pretty simple but saves a bit of typing.

String.format("${cursor}",)

Answer 10

A little tip on sysout -- I like to renamed it to "sop". Nothing else in the java libs starts with "sop" so you can quickly type "sop" and boom, it inserts.

Answer 11

Format a string

MessageFormat - surround the selection with a MessageFormat.

 ${:import(java.text.MessageFormat} 
 MessageFormat.format(${word_selection}, ${cursor})

This lets me move a cursor to a string, expand the selection to the entire string (Shift-Alt-Up), then Ctrl-Space twice.

Lock the selection

lock - surround the selected lines with a try finally lock. Assume the presence of a lock variable.

${lock}.acquire();
try {
    ${line_selection}
    ${cursor}
} finally {
    ${lock}.release();
}

NB ${line_selection} templates show up in the Surround With menu (Alt-Shift-Z).

Answer 12

And an equalsbuilder, hashcodebuilder adaptation:

${:import(org.apache.commons.lang.builder.EqualsBuilder,org.apache.commons.lang.builder.HashCodeBuilder)}
@Override
public boolean equals(Object obj) {
    return EqualsBuilder.reflectionEquals(this, obj);
}

@Override
public int hashCode() {
    return HashCodeBuilder.reflectionHashCode(this);
}

Answer 13

Throw an IllegalArgumentException with variable in current scope (illarg):

throw new IllegalArgumentException(${var});

Answer 14

The template for the logger declaration is great.

I also create linfo, ldebug, lwarn, lerror for the log levels that I use more often.

lerror:

logger.error(${word_selection}${});${cursor}

Answer 15

My favorite few are...

1: Javadoc, to insert doc about the method being a Spring object injection method.

 Method to set the <code>I${enclosing_type}</code> implementation that this class will use.
* 
* @param ${enclosing_method_arguments}<code>I${enclosing_type}</code> instance 

2: Debug window, to create a FileOutputStream and write the buffer's content's to a file. Used for when you want to compare a buffer with a past run (using BeyondCompare), or if you can't view the contents of a buffer (via inspect) because its too large...

java.io.FileOutputStream fos = new java.io.FileOutputStream( new java.io.File("c:\\x.x"));
fos.write(buffer.toString().getBytes());
fos.flush();
fos.close();

Answer 16

I know I am kicking a dead post, but wanted to share this for completion sake:

A correct version of singleton generation template, that overcomes the flawed double-checked locking design (discussed above and mentioned else where)

Singleton Creation Template: Name this as createsingleton, and

static enum Singleton {
    INSTANCE;

    private static final ${enclosing_type} singleton = new ${enclosing_type}();

    public ${enclosing_type} getSingleton() {
        return singleton;
    }
}
${cursor}

To access singletons generated using above:

Singleton reference Template: Name this ias getsingleton,

${type} ${newName} = ${type}.Singleton.INSTANCE.getSingleton();

Answer 17

Some more templates here.

Includes:

• Create a date object from a particular date
• Create a new generic ArrayList
• Logger setup
• Log with specified level
• Create a new generic HashMap
• Iterate through a map, print the keys and values
• Parse a time using SimpleDateFormat
• Read a file line by line
• Log and rethrow a caught exeption
• Print execution time of a block of code
• Create periodic Timer
• Write a String to a file

Answer 18

When did you use "${word_selection}${}" What it means?