Getting unchecked result of Future with Guava

If you like Java Executor Framework as much as I do (and hate checked exceptions as much as I do), then you probably start to swear each time you need to handle all these annoying checked exceptions of Future#get.

Future<MyMessage> response =
  camelProducerTemplate.asyncRequestBody(
    "http://veryslow.com/esb/service",
    "request", MyMessage.class);
...
// Do something else waiting for the HTTP response.
...
try {
  handleResponse(response.get());
} catch (InterruptedException e) {
  throw new RuntimeException(e);
} catch (ExecutionException e) {
  throw new RuntimeException(e);
}

Handling checked exceptions of Future is especially annoying, as Executor Framework is widely used when implementing popular Request-Reply pattern in messaging systems.

Fortunately Guava's Futures utility provides glue code for handling Future#get exceptions. This extremely useful method is called getUnchecked.

import static com.google.common.util.concurrent.Futures.getUnchecked;
...
Future<MyMessage> response =
  camelProducerTemplate.asyncRequestBody(
    "http://veryslow.com/esb/service",
    "request", MyMessage.class);
...
// Do something else waiting for the HTTP response.
...
handleResponse(getUnchecked(response));

Thank you Google.

Hello Huava

Guava is cool. Nice idea to have all the missing Java utils in one place.

However Google guys don't included in Guava all the utils I dream of. That's why I created Huava - project where I put my magic utils designed in the fashion similar to Guava.

Iterable transformations using Guava

I love Groovy for spread operator (for example users*.name). Google Guava allows you to do the same using the Function interface and Iterables.transform() method.

Function<Date, Integer> YEAR = new Function<Date, Integer>() {

  public Integer apply(Date date) {
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(date);
    return calendar.get(Calendar.YEAR);
  }

};

Date[] dates = {new Date(), new Date(), new Date()};
Iterable<Integer> yearsIterable = Iterables.transform(Lists.newArrayList(dates), YEAR);
List<Integer> years = Lists.newArrayList(yearsIterable);

System.out.println(years);

Guava Files util - my top methods

Guava makes Java code more Groovy-like. Now say hello to the Spring IO utils and Ant. Introducing com.google.common.io.Files:

// Just write this fuckin' String to the file, man...
static void write(CharSequence from, File to, Charset charset)
static void append(CharSequence from, File to, Charset charset)

// File system operations
static void copy(File from, File to) 
static void deleteDirectoryContents(File directory)
static void deleteRecursively(File file)
static void move(File from, File to) 
static void touch(File file)

// No more annoying Java IO
static void createParentDirs(File file)
static File createTempDir()
static BufferedReader newReader(File file, Charset charset)
static BufferedWriter newWriter(File file, Charset charset) 
static List<String> readLines(File file, Charset charset)

Guava Object helpers

Say hello to the Spring utils.

import com.google.common.base.Objects;

// Null-safe equals
Objects.equal("foo", null);

// Choose first not-null or throw NPE
Objects.firstNonNull("foo", null);

// Helper for Arrays.hashCode()
Objects.hashCode(1, "foo", null);

// ToStringHelper which generates - String{foo, bar, baz=qux}
String toStringTarget = "foo";
Objects.toStringHelper(toStringTarget).
   addValue(toStringTarget).addValue("bar").add("baz", "qux");