Implement the collect function on list<T> - Java Lambda Stream

Java examples for Lambda Stream:Collector

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Description

Implement the collect function on list<T>

Demo Code

import java.util.List;
import java.util.stream.Collector;

public class Main {

  /**//from   w  w w  . j  a v a 2 s . co m
   * Implement the collect function on list<T>. The result should be equivalent to
   * the execution of the code:
   * 
   * <pre>
   * list.stream().collect(col);
   * </pre>
   * 
   * 
   * @param list
   * @param col
   *          a collector of type Collector<T,A,R>
   * @return a value of type R.
   */

  public static <T, A, R> R collect(List<T> list, Collector<T, A, R> col) {
    // The result should be equivalent to the code:
    // list.stream().collect(col) ;

    A result = col.supplier().get();
    list.forEach(t -> col.accumulator().accept(result, t));
    return col.finisher().apply(result);
  }
}

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