package ReadWriteLock.A3_1;public final class ReadWriteLock {
private int readingReaders = 0; // (A)...实际正在读取的执行绪数量
private int waitingWriters = 0; // (B)...正在等待写入的执行绪数量
private int writingWriters = 0; // (C)...实际正在写入的执行绪数量
private boolean preferWriter = true; // 写入优先的话,值为true public synchronized void readLock() throws InterruptedException {
while (writingWriters > 0 || (preferWriter && waitingWriters > 0)) {
wait();
}
readingReaders++; // (A)实际正在读取的线程数量加1
} public synchronized void readUnlock() {
readingReaders--; // (A)实际正在读取的线程数量减1
preferWriter = true;
notifyAll();
} public synchronized void writeLock() throws InterruptedException {
waitingWriters++; // (B)正在等待写入的线程数量加1
try {
while (readingReaders > 0 || writingWriters > 0) {
wait();
}
} finally {
waitingWriters--; // (B)正在等待写入的线程数量减1
}
writingWriters++; // (C)实际正在写入的线程数量加1
} public synchronized void writeUnlock() {
writingWriters--; // (C)实际正在写入的线程数量减
preferWriter = false;
notifyAll();
}
}package ReadWriteLock.A3_1;public class Data {
private final char[] buffer;
private final ReadWriteLock lock = new ReadWriteLock();
public Data(int size) {
this.buffer = new char[size];
for (int i = 0; i < buffer.length; i++) {
buffer[i] = '*';
}
}
public char[] read() throws InterruptedException {
lock.readLock();
try {
return doRead();
} finally {
lock.readUnlock();
}
}
public void write(char c) throws InterruptedException {
lock.writeLock();
try {
doWrite(c);
} finally {
lock.writeUnlock();
}
}
private char[] doRead() {
char[] newbuf = new char[buffer.length];
for (int i = 0; i < buffer.length; i++) {
newbuf[i] = buffer[i];
}
slowly();
return newbuf;
}
private void doWrite(char c) {
for (int i = 0; i < buffer.length; i++) {
buffer[i] = c;
slowly();
}
}
private void slowly() {
try {
Thread.sleep(50);
} catch (InterruptedException e) {
}
}
}这个怎么使读读相互不排斥?因为synchronized加锁的是对象,然后只要进入读方法后,另一个读方法得等前一个线程读完后再进入读?
我哪里理解错了?
private int readingReaders = 0; // (A)...实际正在读取的执行绪数量
private int waitingWriters = 0; // (B)...正在等待写入的执行绪数量
private int writingWriters = 0; // (C)...实际正在写入的执行绪数量
private boolean preferWriter = true; // 写入优先的话,值为true public synchronized void readLock() throws InterruptedException {
while (writingWriters > 0 || (preferWriter && waitingWriters > 0)) {
wait();
}
readingReaders++; // (A)实际正在读取的线程数量加1
} public synchronized void readUnlock() {
readingReaders--; // (A)实际正在读取的线程数量减1
preferWriter = true;
notifyAll();
} public synchronized void writeLock() throws InterruptedException {
waitingWriters++; // (B)正在等待写入的线程数量加1
try {
while (readingReaders > 0 || writingWriters > 0) {
wait();
}
} finally {
waitingWriters--; // (B)正在等待写入的线程数量减1
}
writingWriters++; // (C)实际正在写入的线程数量加1
} public synchronized void writeUnlock() {
writingWriters--; // (C)实际正在写入的线程数量减
preferWriter = false;
notifyAll();
}
}package ReadWriteLock.A3_1;public class Data {
private final char[] buffer;
private final ReadWriteLock lock = new ReadWriteLock();
public Data(int size) {
this.buffer = new char[size];
for (int i = 0; i < buffer.length; i++) {
buffer[i] = '*';
}
}
public char[] read() throws InterruptedException {
lock.readLock();
try {
return doRead();
} finally {
lock.readUnlock();
}
}
public void write(char c) throws InterruptedException {
lock.writeLock();
try {
doWrite(c);
} finally {
lock.writeUnlock();
}
}
private char[] doRead() {
char[] newbuf = new char[buffer.length];
for (int i = 0; i < buffer.length; i++) {
newbuf[i] = buffer[i];
}
slowly();
return newbuf;
}
private void doWrite(char c) {
for (int i = 0; i < buffer.length; i++) {
buffer[i] = c;
slowly();
}
}
private void slowly() {
try {
Thread.sleep(50);
} catch (InterruptedException e) {
}
}
}这个怎么使读读相互不排斥?因为synchronized加锁的是对象,然后只要进入读方法后,另一个读方法得等前一个线程读完后再进入读?
我哪里理解错了?
解决方案 »
- 新手求解释~~~~~~~
- 如何使cmd默认为F盘
- thinking in java实例解释
- 如何去掉指定Jtable某一列的焦点?
- 推荐几篇不靠谱的帖子
- 如何装ant阿?下载完后该如何使用以及配置阿
- 如何将JAVA程序的图标放在系统栏里(即任务栏右边的区域,跟输入法图标排在一起)?
- 有愿意帮我看一下程序的解决方法,我是一个很菜的新手:)
- (JMF) how to adjust the capturing volume(microphone)?
- 怎么在DataBase组件中使用纯JDBC连接Sql server 7数据库?
- 大牛帮帮忙,怎么在tableviewer某一列中添加进度条。
- 如何让没有装JDK 配置环境的机子运行.jar
char[] newbuf = new char[buffer.length];
for (int i = 0; i < buffer.length; i++) {
newbuf[i] = buffer[i];
}
slowly();
return newbuf;
}改为
private char[] doRead() {
char[] newbuf = new char[buffer.length];
for (int i = 0; i < buffer.length; i++) {
newbuf[i] = buffer[i];
slowly();//这能才能有效果
}
//slowly();
return newbuf;
}