某App需要从设备上下载一段录像，为提高下载速度，需要同时开启两个线程A和B，分别进行下载，并且在下载后录像片段以二叉树的形式存储，假如某一录像有10个片段，由{片段1，片段2....，片段10}组成，其下载后的存储结构如下：
1
/
2 3
/ /\
4 5 6
\ /
7 8 9
10
请实现com.regan.text.Record类，该类主要实现如下属性：
/**
* 模拟二叉树下载，参考https://segmentfault.com/a/1190000014743964
*
* @author Regan
* @time 2019/07/19
**/
public class Record {
private Record rootRecord;
private int recordIndex;//录像片段索引
private Record leftRecord;
private Record rightRecord;
public Record() {
}
public Record(Record record) {
this.rootRecord = record;
}
public Record getRootRecord() {
return rootRecord;
}
public void setRootRecord(Record rootRecord) {
this.rootRecord = rootRecord;
}
public int getRecordIndex() {
return recordIndex;
}
public void setRecordIndex(int recordIndex) {
this.recordIndex = recordIndex;
}
public Record getLeftRecord() {
return leftRecord;
}
public void setLeftRecord(Record leftRecord) {
this.leftRecord = leftRecord;
}
public Record getRightRecord() {
return rightRecord;
}
public void setRightRecord(Record rightRecord) {
this.rightRecord = rightRecord;
}
private static Thread A;
private static MyRunable ARun;
private static Thread B;
private static MyRunable BRun;
private static int currentIndex = 0;
/**
* 1
* / \
* 2 3
* / /\
* 4 5 6
* \ / \
* 7 8 9
* \
* 10
* downloadRecord方法同时开启线程A和B，其中线程A下载（打印）奇数片段，线程B下载（打印）偶数片段，并使得片段按顺序输出，返回"线程名+片段索引"的列表，
* 参数rootRecord为二叉树的根结点，在样例中指索引为1这个节点，属性recordIndex为1，如样例索引的输出结果为（A1B2A3B4A5B6A7B8A9B10）
*/
public static String downloadRecord(final Record oldRecord, final Record newRecord) {
if(newRecord == null){
return "";
}
try {
Thread.sleep(1000);//等一下
} catch (InterruptedException e) {
e.printStackTrace();
}
// 索引%2=1的话代表是奇数，反之也为偶数
if (newRecord.getRecordIndex() % 2 == 1) {
ARun = new MyRunable("A", newRecord);
A = new Thread(ARun);
A.start();
if(oldRecord != null){
// System.out.println("A:::old:" + oldRecord.getRecordIndex() + "->new:" + newRecord.getRecordIndex());
}
if (newRecord.height(newRecord) == 0) {
A.interrupt();
}
} else {
BRun = new MyRunable("B", newRecord);
B = new Thread(BRun);
B.start();
if(oldRecord != null){
// System.out.println("A:::old:" + oldRecord.getRecordIndex() + "->new:" + newRecord.getRecordIndex());
}
if (newRecord.height(newRecord) == 0) {
B.interrupt();
}
}
return "";
}
public static class MyRunable implements Runnable {
private String threadName;
private Record record;
static private Object ob = new Object();
public MyRunable(String threadName, Record record) {
this.threadName = threadName;
this.record = record;
}
public synchronized void setRecord(Record record) {
this.record = record;
}
@Override
public void run() {
Random random = new Random();
try {
int time = random.nextInt(10000);
Thread.sleep(time);//模拟下载时间
// System.out.println("currentIndex : " + currentIndex + " " +
// "ThreadName:" + threadName + " 模拟下载时间 record: " + record.getRecordIndex() + " download time: " + time);
} catch (InterruptedException e) {
e.printStackTrace();
}
// synchronized (ob){
if (record.getRecordIndex() - currentIndex != 1) {
System.out.println("currentIndex: " + currentIndex + " 还没轮到你，拦截住:" + record.getRecordIndex());
synchronized (ob) {
try {
ob.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
if (record.getRecordIndex() - currentIndex != 1) {
try {
ob.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("download done ThreadName:" + threadName + " RecordIndex:" + record.getRecordIndex());
currentIndex = record.getRecordIndex();
if(record.getLeftRecord() != null) {
Record.downloadRecord(record, record.getLeftRecord());
}
if(record.getRightRecord() != null) {
Record.downloadRecord(record, record.getRightRecord());
}
}
}else{
synchronized (ob) {
System.out.println("download done ThreadName:" + threadName + " RecordIndex:" + record.getRecordIndex());
currentIndex = record.getRecordIndex();
ob.notifyAll();
if(record.getLeftRecord() != null) {
Record.downloadRecord(record, record.getLeftRecord());
}
if(record.getRightRecord() != null) {
Record.downloadRecord(record, record.getRightRecord());
}
}
}
// }
}
// }
}
}
/**
* 对二叉树存储的录像片段索引进行前序遍历，返回索引遍历顺序
* */
public static String preOrder(Record rootRecord) {
String order = "";
if(rootRecord != null) {
order += rootRecord.recordIndex + " ";
order += preOrder(rootRecord.getLeftRecord()) + " ";
order += preOrder(rootRecord.getRightRecord()) + " ";
}
return order;
}
/**
* 对二叉树存储的录像片段进行中序遍历，返回索引遍历顺序
*/
public static String middleOrder(Record rootRecord) {
String order = "";
if(rootRecord != null) {
order += middleOrder(rootRecord.getLeftRecord()) + " ";
order += rootRecord.recordIndex + " ";
order += middleOrder(rootRecord.getRightRecord()) + " ";
}
return order;
}
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