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private List<Movie> movieItems = null;
public List<Movie> getMovieItems() {
final int first = 0;
if (movieItems == null) {
getPagingInfo();
movieItems = jpaController.findRange(new int[]{pagingInfo.getFirstItem(), pagingInfo.getFirstItem() + pagingInfo.getBatchSize()});
Collections.sort(movieItems, new Comparator(){
public int compare (Object o1, Object o2){
Date d1 = movieItems.get(((Movie)o1).getMovieId()).getDate();
Date d2 = movieItems.get(((Movie)o2).getMovieId()).getDate();
if(d1.before(d2)){
movieItems.set(1, (Movie)o1);
movieItems.set(2, (Movie)o2);
}
return first;
}
});
}
return movieItems;
}
jpaController is bringing back 4 movies and is giving me the following
java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 4 at java.util.Vector.get(Vector.java:694) at entitybeans.jsf.PeliculaController$1.compare(PeliculaController.java:260) at java.util.Arrays.mergeSort(Arrays.java:1270) at java.util.Arrays.sort(Arrays.java:1210) at java.util.Collections.sort(Collections.java:159) at entitybeans.jsf.PeliculaController.getPeliculaItems(PeliculaController.java:257) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at javax.el.BeanELResolver.getValue(BeanELResolver.java:302) at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:175) at com.sun.faces.el.FacesCompositeELResolver.getValue(FacesCompositeELResolver.java:72) at com.sun.el.parser.AstValue.getValue(AstValue.java:116) at com.sun.el.parser.AstValue.getValue(AstValue.java:163)....
340
sort() method to sort a list of objects using some examples. By default, the sort() method sorts a given list into ascending order (or natural order). We can use Collections. reverseOrder() method, which returns a Comparator, for reverse sorting.
Inside the compare method for return value use the compareTo() method which will return the specified value by comparing the DateItem objects. Now in the main method use Collections. sort() method and pass the ArrayList and 'SortItem' class object to it, it will sort the dates, and output will be generated.
Java 8 introduced a sort method in the List interface which can use a comparator. The Comparator. comparing() method accepts a method reference which serves as the basis of the comparison. So we pass User::getCreatedOn to sort by the createdOn field.
In the main() method, we've created an array list of custom objects list, initialized with 5 objects. For sorting the list with the given property, we use the list's sort() method. The sort() method takes the list to be sorted (final sorted list is also the same) and a comparator.
In your compare method, o1 and o2 are already elements in the movieItems list. So, you should do something like this:
Collections.sort(movieItems, new Comparator<Movie>() {
public int compare(Movie m1, Movie m2) {
return m1.getDate().compareTo(m2.getDate());
}
});
Do not access or modify the collection in the Comparator. The comparator should be used only to determine which object is comes before another. The two objects that are to be compared are supplied as arguments.
Date itself is comparable, so, using generics:
class MovieComparator implements Comparator<Movie> {
public int compare(Movie m1, Movie m2) {
//possibly check for nulls to avoid NullPointerException
return m1.getDate().compareTo(m2.getDate());
}
}
And do not instantiate the comparator on each sort. Use:
private static final MovieComparator comparator = new MovieComparator();
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