java - 如何检查 Builder 模式类中的无效输入？

Question

下面是我的构建器类，其中两个字段是必需的，即 userId 和 clientId。

public final class InputKeys {

    private final long userId;
    private final int clientId;
    private final long timeout;
    private final Preference preferences;
    private final boolean debugFlag;
    private final Map<String, String> attributeMap;

    private InputKeys(Builder builder) {
    this.userId = builder.userId;
    this.clientId = builder.clientId;
    this.preferences = builder.preference;
    this.attributeMap = builder.attributeMap;
    this.timeout = builder.timeout;
    this.debugFlag = builder.debugFlag;
    }

    public static class Builder {
    protected final long userId;
    protected final int clientId;
    protected long timeout = 500L;
    protected Preference preference;
    protected boolean debugFlag;
    protected Map<String, String> attributeMap;


    public Builder(long userId, int clientId) {
        this.userId = userId;
        this.clientId = clientId;
    }

    public Builder attributeMap(Map<String, String> attributeMap) {
        this.attributeMap = attributeMap;
        return this;
    }

    public Builder preference(Preference preference) {
        this.preference = preference;
        return this;
    }

    public Builder debugFlag(boolean debugFlag) {
        this.debugFlag = debugFlag;
        return this;
    }

    public Builder timeout(long timeout) {
        this.timeout = timeout;
        return this;
    }

    public InputKeys build() {
        return new InputKeys(this);
    }
    }

    //getters  here
}

现在我将这样调用这个构建器类 -

InputKeys keys = new InputKeys.Builder(12000L, 33L).build();

但是有人可能会传递错误的输入值，例如传递负的 userId 和负的 clientId、负的超时值或空的 attributeMap。如何在我的构建器类中处理这些情况？

如果我对 if else if block 中的每个变量进行 IllegalArgumentcheck，那么我的整个 Builder 类都会被 IllegalArgumentException 检查淹没吗？

有更好的方法吗？

Answer 1

创建具有共同逻辑的方法，例如

private void assertNonNegative(long val, String attr) {
    if (val < 0) {
         throw IllegalArgumentException(attr + " cannot be negative");
    }
}