用java编写实现银行家算法,在算法执行过程中,首先判断申请资源的进程所申请的资源数目是否合法,若合法,则可以为其进行试分配,再利用安全性算法判断是否存在安全序列,若存在,则说明可以给申请资源的进程分配资源。否则,不进行资源的分配。分别创建进程类、银行家算法类、测试类 【设计要求】 1.创建二维数组等数据结构用来表示进程对资源的使用情况,相关数据包括进程名称、进程数目、资源数目、最大需求数目、已分配数目、仍需数目及当前状态下可利用数目等。 2.在用户输入所有初始化信息后,首先对信息以矩阵形式输出,再输入一组可用资源数目,此时系统判断是否存在安全序列,若有则输出一个安全序列;若无,则表示初始化不正确,请重新输入。 3.在已经处于安全状态的前提下,某进程提出新的资源申情,包括进程名称、申请资源数目等,先对用户提出的请求进行合法性检查,若请求合法,则进行试分配。最后对试分配后的状态,调用安全性检查算法进行是否存在安全序列的判断。若安全,给出分配后资源使用情况,并输出一个安全序列。否则,拒绝申请并打印出相应的拒绝原因。
时间: 2024-03-10 20:43:46 浏览: 102
好的,你的问题是如何实现银行家算法的Java代码,对吗?
首先,我们需要创建一个进程类,其中包含进程名称、进程数目、资源数目、最大需求数目、已分配数目、仍需数目及当前状态下可利用数目等数据:
```java
public class Process {
private String name;
private int processNum;
private int resourceNum;
private int[][] maxNeed;
private int[][] allocated;
private int[][] need;
private boolean finished;
// getters and setters here
}
```
然后,我们需要创建一个银行家算法类,其中包含银行家算法的主要逻辑:
```java
public class BankerAlgorithm {
private int[] available;
private List<Process> processes;
// getters and setters here
public boolean isSafe() {
int numProcesses = processes.size();
int numResources = available.length;
boolean[] finished = new boolean[numProcesses];
int[] work = Arrays.copyOf(available, numResources);
int count = 0;
int[] safeSequence = new int[numProcesses];
while (count < numProcesses) {
boolean found = false;
for (int i = 0; i < numProcesses; i++) {
if (!finished[i] && isNeedLessOrEqual(work, processes.get(i).getNeed())) {
work = add(work, processes.get(i).getAllocated());
finished[i] = true;
found = true;
safeSequence[count] = i;
count++;
}
}
if (!found) {
return false;
}
}
return true;
}
public boolean requestResources(int processIndex, int[] request) {
Process process = processes.get(processIndex);
if (!isNeedLessOrEqual(request, process.getNeed())) {
return false;
}
if (!isNeedLessOrEqual(request, available)) {
return false;
}
int[][] newAllocated = add(process.getAllocated(), request);
int[][] newNeed = subtract(process.getMaxNeed(), newAllocated);
BankerAlgorithm tempBanker = new BankerAlgorithm(
Arrays.copyOf(available, available.length),
new ArrayList<>(processes)
);
tempBanker.getProcesses().get(processIndex).setAllocated(newAllocated);
tempBanker.getProcesses().get(processIndex).setNeed(newNeed);
if (tempBanker.isSafe()) {
process.setAllocated(newAllocated);
process.setNeed(newNeed);
available = subtract(available, request);
return true;
} else {
return false;
}
}
// helper methods here
}
```
最后,我们需要创建一个测试类,用于测试银行家算法的正确性:
```java
public class BankerAlgorithmTest {
public static void main(String[] args) {
int[] available = {3, 3, 2};
int[][] maxNeed = {
{7, 5, 3},
{3, 2, 2},
{9, 0, 2},
{2, 2, 2},
{4, 3, 3}
};
int[][] allocated = {
{0, 1, 0},
{2, 0, 0},
{3, 0, 2},
{2, 1, 1},
{0, 0, 2}
};
BankerAlgorithm banker = new BankerAlgorithm(available, maxNeed, allocated);
System.out.println("Initial state:");
banker.printState();
int[] request1 = {1, 0, 2};
if (banker.requestResources(0, request1)) {
System.out.println("Request 1 approved:");
banker.printState();
} else {
System.out.println("Request 1 denied");
}
int[] request2 = {0, 2, 0};
if (banker.requestResources(1, request2)) {
System.out.println("Request 2 approved:");
banker.printState();
} else {
System.out.println("Request 2 denied");
}
int[] request3 = {3, 0, 0};
if (banker.requestResources(2, request3)) {
System.out.println("Request 3 approved:");
banker.printState();
} else {
System.out.println("Request 3 denied");
}
}
}
```
这样,我们就完成了银行家算法的Java实现。
阅读全文