实验二 银行家算法Word文档下载推荐.docx
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它表示系统是否有足够的资源分配给进程，使之运行完成，开始Finish（I）=false；
当有足够资源分配给进程Pi时，令Finish（i）=true；
2．从进程集合中找到一个能满足下述条件的进程。
Finish（i）==false；
Needi≤work；
如找到则执行步骤3；
否则，执行步骤4；
3．当进程Pi获得资源后，可顺利执行直到完成，并释放出分配给它的资源，故应执行
Work=work+Allocationi
Finish（i）=true；
转向步骤2；
4．若所有进程的Finish（i）都为true，则表示系统处于安全状态；
否则，系统处于不安全状态。
六、流程图
七、源程序代码
1．银行家算法类
packageBankerAlgorithm;
publicclassBanker{
privateint[]Available;
//可利用资源向量
privateint[]AllSource;
//总资源数
privateint[][]Max;
//最大需求矩阵
privateint[][]Allocation;
//已分配资源矩阵
privateint[][]Need;
//需求矩阵
privateint[]Work;
//工作向量
privateint[]Request;
//资源请求向量
privateint[]Temp;
//交换向量
//privateboolean[]Finish;
//判断进程是否可以得到资源
privateintprocessCount;
//进程数
privateintsourceCount;
//资源数
privateStringsafeList=newString（）;
privateintcount;
privateString[][]dataStrings;
privateintflag;
publicvoidinitBanker（intprocessCount,intsourceCount）{
this.processCount=processCount;
this.sourceCount=sourceCount;
this.Max=newint[processCount][sourceCount];
this.Allocation=newint[processCount][sourceCount];
this.Need=newint[processCount][sourceCount];
this.Work=newint[sourceCount];
this.Request=newint[sourceCount];
//this.Finish=newboolean[processCount];
this.dataStrings=newString[processCount][6];
this.Temp=newint[processCount];
for（inti=0;
i<
processCount;
i++）{
for（intj=0;
j<
6;
j++）{
dataStrings[i][j]=newString（）;
}
}
}
publicvoidinitMaxAllocationNeed（int[][]max,int[][]allocation,int[][]need,introw）{//初始化其余矩阵
sourceCount;
this.Max[row-1][i]=max[row-1][i];
this.Allocation[row-1][i]=allocation[row-1][i];
this.Need[row-1][i]=need[row-1][i];
publicvoidinitAvailable（intsourceCount,int[]available）{//初始化可利用资源矩阵
this.Available=newint[sourceCount];
this.Available[i]=available[i];
publicvoidinitAllSource（intsourceCount,int[]available）{//初始化资源总数矩阵
this.AllSource=newint[sourceCount];
this.AllSource[i]=available[i];
publicvoidinitTemp（int[]temp,introw）{//初始化临时矩阵
this.Temp[row-1]=temp[row-1];
publicvoidinitRequest（int[]request）{//初始化请求矩阵
this.Request[i]=request[i];
publicbooleanisEnoughAll（int[]max）{//检查最大资源矩阵是否小于资源总数
if（max[i]>
AllSource[i]）{
returnfalse;
returntrue;
publicbooleanisMaxAllocation（int[]max,int[]allocation）{//检查已分配资源数是否小于最大资源数
if（allocation[i]>
max[i]）{
publicbooleanisEnoughNeed（introw）{//工作向量是否满足需求矩阵
if（Need[row][i]>
Work[i]）{
this.flag=0;
this.flag=1;
publicbooleanisEnoughReq（introw）{//请求矩阵是否满足需求矩阵
if（Need[row][i]<
Request[i]）{
publicbooleanisEnoughAva（introw）{//请求矩阵是否满足需求矩阵
if（Request[i]>
Available[i]）{
publicbooleanisAvailable（int[]available）{
if（available[i]<
0）{
publicbooleancheckNeed（int[]need）{//检查需求矩阵中资源是否都为0
if（need[i]!
=0）{
}
publicbooleanisSafe（）{//检查是否安全
inti;
for（i=0;
i<
processCount;
i++）{
if（isEnoughNeed（Temp[i]-1））{
CountWork（Temp[i]-1）;
continue;
elsebreak;
if（i==processCount）returntrue;
elsereturnfalse;
publicvoidCountWork（introw）{//计算工作向量
Work[i]=Work[i]+Allocation[row][i];
publicvoidgetSafeList（intk,intn）{//递归求安全序列
intm,a;
if（k==n）{
for（intj=0;
j<
sourceCount;
j++）
Work[j]=Available[j];
if（isSafe（））{
for（a=0;
a<
processCount-1;
a++）
safeList+=Temp[a]+"
->
"
;
safeList+=Temp[a]+"
+"
\n"
count++;
for（intj=0;
j<
j++）
Work[j]=Available[j];
}else{
for（inti=k;
i<
=n;
i++）{//排列
m=Temp[k];
Temp[k]=Temp[i];
Temp[i]=m;
getSafeList（k+1,n）;
publicvoidchangeDataString（）{//设置数据
Strings_available=newString（）;
Strings_allocation=newString（）;
Strings_need=newString（）;
Strings_max=newString（）;
s_available+=this.Available[j]+"
"
s_allocation+=this.Allocation[i][j]+"
s_need+=this.Need[i][j]+"
s_max+=this.Max[i][j]+"
this.dataStrings[i][1]=i+1+"
this.dataStrings[i][2]=s_max;
this.dataStrings[i][3]=s_allocation;
this.dataStrings[i][4]=s_need;
this.dataStrings[0][5]=s_available;
publicvoidallocateSource（introw）{
if（checkNeed（Need[i]））{
for（intj=0;
this.Available[j]+=this.Allocation[i][j];
this.Allocation[i][j]=0;
this.Max[i][j]=0;
}
for（inti=0;
this.Available[i]=this.Available[i]-this.Request[i];
this.Allocation[row-1][i]=this.Allocation[row-1][i]+this.Request[i];
this.Need[row-1][i]=this.Need[row-1][i]-this.Request[i];
changeDataString（）;
publicbooleanrequestSource（introw）{
count=0;
if（isEnoughReq（row-1）&
&
isEnoughAva（row-1））{
allocateSource（row）;
returntrue;
returnfalse;
publicint[]getAvailable（）{
returnAvailable;
publicvoidsetAvailable（int[]available）{
Available=available;
publicStringgetSafeList（）{
returnsafeList;
publicvoidsetSafeList（StringsafeList）{
this.safeList=safeList;
publicintgetCount（）{
returncount;
publicvoidsetCount（intcount）{
this.count=count;
publicString[][]getDataStrings（）{
returndataStrings;
publicvoidsetDataStrings（String[][]dataStrings）{
this.dataStrings=dataStrings;
publicintgetFlag（）{
returnflag;
publicvoidsetFlag（intflag）{
this.flag=flag;
}
2．界面类
importorg.eclipse.swt.widgets.Display;
importorg.eclipse.swt.widgets.Shell;
importorg.eclipse.swt.SWT;
importorg.eclipse.swt.widgets.Label;
importorg.eclipse.swt.widgets.MessageBox;
importorg.eclipse.swt.widgets.TableItem;
importorg.eclipse.swt.widgets.Text;
importorg.eclipse.swt.widgets.Button;
importorg.eclipse.swt.widgets.Table;
importorg.eclipse.swt.widgets.TableColumn;
importorg.eclipse.swt.events.SelectionAdapter;
importorg.eclipse.swt.events.SelectionEvent;
importorg.eclipse.swt.custom.ScrolledComposite;
importorg.eclipse.wb.swt.SWTResourceManager;
publicclassBankerSWT{
protectedShellshell;
privateTextsourceCountText;
privateTextproCountText;
privateTextcountText;
privateText[]sourceTexts=newText[10];
privateText[]maxTexts=newText[10];
privateText[]allocationTexts=newText[10];
privateText[]requestTexts=newText[10];
privateButtonbutton;
privateLabellabel_2;
privateButtonbutton_1;
privateLabellabel_3;
privateLabellabel_4;
privateButtonbutton_2;
privateLabellblNewLabel;
privateTabletable;
privateTextrequsetText;
privateTextsecurityText;
privateintrow;
privateBankerbanker=newBanker（）;
/**
*Launchtheapplication.
*@paramargs
*/
publicstaticvoidmain（String[]args）{
try{
BankerSWTwindow=newBankerSWT（）;
window.open（）;
}catch（Exceptione）{
e.printStackTrace（）;
*Openthewindow.
publicvoidopen（）{
Displaydisplay=Display.getDefault（）;
createContents（）;
shell.open（）;
shell.layout（）;
while（!
shell.isDisposed（））{
if（!
display.readAndDispatch（））{
display.sleep（）;
*Createcontentsofthewindow.
protectedvoidcreateContents（）{
shell=newShell（）;
shell.setSize（550,475）;
shell.setText（"
银行家算法"
）;
Labellabel=newLabel（shell,SWT.NONE）;
label.setBounds（10,10,84,17）;
label.setText（"
\u8BF7\u8F93\u5165\u8D44\u6E90\u6570\uFF1A"
sourceCountText=newText（shell,SWT.BORDER）;
sourceCountText.setBounds（100,10,
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