Java Stream - 如何创建Consumer lambda

import java.util.function.Consumer;

public class Main {

  public static void main(String[] args) {
    Consumer<Trade> consumer = x -> x.setQuantity(x.getQuantity()*2);
    Trade t = new Trade(1,"XT",1000,"NEW");
    System.out.println("T's qty before :"+t.getQuantity());
    consumer.accept(t);
    System.out.println("T's qty after :"+t.getQuantity());
  }

}


class Trade {

  private int tradeId = 0;
  private String issuer = null;
  private int quantity = 0;
  private String status = null;

  public Trade(int id, String issuer, int quantity, String status) {
    this.tradeId = id;
    this.issuer = issuer;
    this.quantity = quantity;
    this.status = status;
  }

  public int getTradeId() {
    return tradeId;
  }

  public void setTradeId(int tradeId) {
    this.tradeId = tradeId;
  }

  public String getIssuer() {
    return issuer;
  }

  public void setIssuer(String issuer) {
    this.issuer = issuer;
  }

  public int getQuantity() {
    return quantity;
  }

  public void setQuantity(int quantity) {
    this.quantity = quantity;
  }

  public String getStatus() {
    return status;
  }

  public void setStatus(String status) {
    this.status = status;
  }

  @Override
  public String toString() {
    return "Trade{" + "tradeId=" + tradeId + ", issuer=" + issuer
        + ", quantity=" + quantity + ", status=" + status + '}';
  }

}