Effective Java 2ed心得1

第二条

第一次试验

public class NuFacts {private final int a;private final int b;private final int c;private final int d;public static class Builder{private final int a;private final int b;private int c = 0;private int d = 0;public Builder(int a, int b) {this.a = a;this.b = b;}public Builder getC(int c) {this.c = c;return this;}public Builder getD(int d) {this.d = d;return this;}public NuFacts build() {return new NuFacts(this);}}private NuFacts(Builder builder) {a = builder.a;b = builder.b;c = builder.c;d = builder.d;}}

public class Nu {private final int a = 0;public static void main(String args[]) {NuFacts nuFact1 = new NuFacts.Builder(100, 10).getC(1).getD(2).build();NuFacts nuFact2 = new NuFacts.Builder(100, 10).getC(1).build();}}