用一个int型保存32个boolean类型的值

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#转自https://www.oschina.net/code/snippet_196697_36379#感谢~~~~~~~

/*这是以前遇到过的一道题目，最近在开源中国找到了比较简单的解决方法。*/

此类是从asp.net源代码中找到的一个很有用的类。现将此类翻译成java。

一个SimpleBitVector32类型的对象能保存32个标志位，相当于32个boolean类型的变量，但在SimpleBitVector32内部只是使用了一个int类型的字段，这样就用一个int类型的变量来替代32个boolean类型的变量，大大节省了内存开销。

/** * Created by Leon on 2017/5/21. */public class SimpleBitVector32{    private int data;    public int getIntegerValue(){        return this.data;    }    public void setIntegerValue(int value){        this.data = value;    }    public boolean getThis(int bit){        return (this.data & bit) == bit;    }    public void setThis(int bit, boolean value){        int num = this.data;        if (value)            this.data = num | bit;        else            this.data = num & ~bit;    }    public int getThis(int mask, int offset){        return (this.data & mask) >> offset;    }    public void setThis(int mask, int offset, int value){        this.data = this.data & ~mask | value << offset;    }    public SimpleBitVector32(int data){        this.data = data;    }    public void set(int bit){        this.data |= bit;    }    public void clear(int bit){        this.data &= ~bit;    }}

测试代码：

/** * Created by Leon on 2017/5/21. */public class Main {    public static void main(String[] args) {        SimpleBitVector32 data = new SimpleBitVector32(0);        System.out.println("The old boolean value at index 0:" + data.getThis(1));        System.out.println("The old boolean value at index 1:" + data.getThis(2));        System.out.println("The old boolean value at index 2:" + data.getThis(2*2));        System.out.println("The old boolean value at index 3:" + data.getThis(2*2*2));        System.out.println("The old boolean value at index 3:" + data.getThis(2*2*2*2));        System.out.println("The old boolean value at index 5:" + data.getThis(2*2*2*2*2));        System.out.println();        data.setThis(1, true);        data.setThis(2, false);        data.setThis(2*2, true);        data.setThis(2*2*2, false);        data.setThis(2*2*2*2, true);        data.setThis(2*2*2*2*2, false);        System.out.println("The new boolean value at index 0:" + data.getThis(1));        System.out.println("The new boolean value at index 1:" + data.getThis(2));        System.out.println("The new boolean value at index 2:" + data.getThis(2*2));        System.out.println("The new boolean value at index 3:" + data.getThis(2*2*2));        System.out.println("The new boolean value at index 4:" + data.getThis(2*2*2*2));        System.out.println("The new boolean value at index 5:" + data.getThis(2*2*2*2*2));        System.out.println("The value inside SimpleBitVector32 is:" + data.getIntegerValue());        System.out.print("//");        for (int i = 31; i >= 0; i--) {            System.out.print(((data.getIntegerValue() & (1 << i)) >>> i));        }    }}

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