filtering an ArrayList using an object's field

Question

I have an ArrayList which is filled by Objects.

My object class called Article which has two fields ;

public class Article {      private int codeArt;     private String desArt;    public Article(int aInt, String string) {         this.desArt = string;         this.codeArt = aInt;     }      public int getCodeArt() {return codeArt; }     public void setCodeArt(int codeArt) {this.codeArt = codeArt;}     public String getDesArt() {return desArt;}     public void setDesArt(String desArt) { this.desArt = desArt;}  } 

I want to filter my List using the desArt field, and for test I used the String "test".

I used the Guava from google which allows me to filter an ArrayList.

this is the code I tried :

private List<gestionstock.Article> listArticles = new ArrayList<>();  //Here the I've filled my ArrayList  private List<gestionstock.Article> filteredList filteredList = Lists.newArrayList(Collections2.filter(listArticles, Predicates.containsPattern("test"))); 

but this code isn't working.

Answer 1

In Java 8, using filter

List<Article> articleList = new ArrayList<Article>(); List<Article> filteredArticleList= articleList.stream().filter(article -> article.getDesArt().contains("test")).collect(Collectors.toList()); 

Answer 2

This is normal: Predicates.containsPattern() operates on CharSequences, which your gestionStock.Article object does not implement.

You need to write your own predicate:

public final class ArticleFilter     implements Predicate<gestionstock.Article> {     private final Pattern pattern;      public ArticleFilter(final String regex)     {         pattern = Pattern.compile(regex);     }      @Override     public boolean apply(final gestionstock.Article input)     {         return pattern.matcher(input.getDesArt()).find();     } } 

Then use:

 private List<gestionstock.Article> filteredList      = Lists.newArrayList(Collections2.filter(listArticles,               new ArticleFilter("test"))); 

However, this is quite some code for something which can be done in much less code using non functional programming, as demonstrated by @mgnyp...