public IssueCollector(IssueFilter issueFilter){
  this.issueFilter=Objects.requireNonNull(issueFilter);
  this.collectedIssues=new LinkedList<>();
}

public IssueCollector ( IssueFilter issueFilter ) { this . issueFilter = Objects . requireNonNull ( issueFilter ) ; this . collectedIssues = new LinkedList < > ( ) ; }
creates a new issue collector instance that accepts only those issues that match the given issue filter .
