《Android源码设计模式解析和实战》建造者模式

建造者模式：用于dialog Glide等；
<pre>
public class Dialog {
private String name;
private String age;

private Dialog() {
}

@Override
public String toString() {
    final StringBuilder sb = new StringBuilder("Dialog{");
    sb.append("name='").append(name).append('\'');
    sb.append(", age='").append(age).append('\'');
    sb.append('}');
    return sb.toString();
}

public static class Builder {
    private static final String TAG = "Builder";
    private Dialog dialog;
    private String name;
    private String age;

    public Builder() {
        dialog = new Dialog();
    }

    public Builder setName(String name) {
        this.name = name;
        return this;
    }

    public Builder setAge(String age) {
        this.age = age;
        return this;
    }

    /**
     * 根据值的有无和不同显示不同的效果
     *
     * @return 返回bulider
     */
    public Builder create() {
        if (age != null && !age.isEmpty()) {
            dialog.age = age;
        }
        if (name != null && !name.isEmpty()) {
            dialog.name = name;
        }
        Log.i(TAG, "create: " + dialog.toString());
        return this;
    }

    public Dialog show() {
        Dialog dialog = new Dialog();
        this.apply(dialog);
        Log.i(TAG, "create: " + dialog.toString());
        return dialog;
    }

    public Dialog apply(Dialog dialog) {
        dialog.name = this.name;
        dialog.age = this.age;
        return dialog;
    }

    public Builder apply(Builder builder) {
        this.name = builder.name;
        this.age = builder.age;
        return builder;
    }
}

}
</pre>
使用：
<pre>
Dialog.Builder builder = new Dialog.Builder().setAge("100").setName("张三").create();
Dialog.Builder builder_1 = new Dialog.Builder().apply(builder).create();
builder_1.setAge("99").create();
Dialog.Builder builder_2 = new Dialog.Builder().create();
Dialog dialog = new Dialog.Builder().apply(builder).show();
</pre>
log:
<pre>
02-28 20:23:19.284 9863-9863/com.lerz.builderdemo I/Builder: create: Dialog{name='张三', age='100'}
02-28 20:23:19.284 9863-9863/com.lerz.builderdemo I/Builder: create: Dialog{name='张三', age='100'}
02-28 20:23:19.284 9863-9863/com.lerz.builderdemo I/Builder: create: Dialog{name='张三', age='99'}
02-28 20:23:19.284 9863-9863/com.lerz.builderdemo I/Builder: create: Dialog{name='null', age='null'}
02-28 20:23:19.284 9863-9863/com.lerz.builderdemo I/Builder: create: Dialog{name='张三', age='99'}
</pre>