RxJavaFromCleanupIterable.java

import rx.Observable;
import rx.functions.Action0;
import rx.functions.Action1;

/**
 * @author stw
 *
 */
public class RXTest {

  /**
   * @param args
   */
  public static void main(String[] args) {
    ComplicatedObject co = new ComplicatedObject();
    Observable<FancyObject> fancy = Observable.from(co);

    fancy.take(3).subscribe(new Action1<FancyObject>() {

      public void call(FancyObject item) {
        System.out.println(item.getName());
      }
    }, new Action1<Throwable>() {

      public void call(Throwable error) {
        System.out.println("Error encountered: " + error.getMessage());
      }
    }, new Action0() {

      public void call() {
        System.out.println("Sequence complete");
      }
    }

    );

  }

}

/* ---------- */

import rx.Observable;
import rx.functions.Action0;
import rx.functions.Action1;

public class RXTest {

  /**
   * @param args
   */
  public static void main(String[] args) {
    ComplicatedObject co = new ComplicatedObject();
    Observable<FancyObject> fancy = Observable.from(co);

    fancy.take(3).subscribe(new Action1<FancyObject>() {

      public void call(FancyObject item) {
        System.out.println(item.getName());
      }
    }, new Action1<Throwable>() {

      public void call(Throwable error) {
        System.out.println("Error encountered: " + error.getMessage());
      }
    }, new Action0() {

      public void call() {
        System.out.println("Sequence complete");
      }
    }

    );

  }

}

/* ---------- */

import java.util.Iterator;
import java.util.Vector;

/**
 * @author stw
 *
 */
public class ComplicatedObject implements Iterator<FancyObject>, Iterable<FancyObject> {

  private boolean isInitialized = false;
  private int fancyCount = 0;
  Vector<FancyObject> allOfThem = new Vector<FancyObject>();

  public boolean hasNext() {

   if (!isInitialized) {
     this.setupAccesstoFancyObject();
   }
   boolean result = fancyCount < this.allOfThem.size();
   if (!result) {
     this.teardownAccessToFancyObjects();
   }

   return result;
  }


  public Iterator<FancyObject> iterator() {
   return this;
  }


  public FancyObject next() {
    FancyObject result = null;
    if (fancyCount < this.allOfThem.size()) {
      result = this.allOfThem.get(fancyCount);
      fancyCount++;
    } 

    return result;
  }


  private void setupAccesstoFancyObject() {
    System.out.println("Initializing fancy objects");
    for (int i = 0; i < 20; i++) {
      this.allOfThem.addElement(new FancyObject());
    }
    this.isInitialized = true;
  }


  private void teardownAccessToFancyObjects() {
    System.out.println("I'm doing proper cleanup here");

  }

}