csupercache.java

队列调度算法的一种

//Source file: E:/工作和学习/工作/硕士论文工作/程序/数据库缓存管理/20040304/src/DBCachePak/CSuperCache.java

/* tangtang */

package DBCachePak;
/**
 * @author
 * @version
 */
public class CSuperCache
{
   private boolean CachLock = false;
   private int tepcn = 0;
   public SuperCacheNode head;
   public SuperCacheNode tail;
   public SuperCacheNode curr;

   /**
    * @param sz
    * @return void
    * @exception
    * @author
    * @version
    * @roseuid 40693E630020
    */
   public CSuperCache(int sz)
   {
     setup();
     if(SuperCacheNode.freelist==null)
     {
     SuperCacheNode temp=new SuperCacheNode(null);
      SuperCacheNode.freelist=temp;
     }
     for(int i=0;i<sz-1;i++)
     {
        SuperCacheNode temp= SuperCacheNode.freelist;
         SuperCacheNode.freelist= new  SuperCacheNode(null);
          SuperCacheNode.freelist.next=temp;
     }
   }

   /**
    * @return void
    * @exception
    * @author
    * @version
    * @roseuid 406B7A6F00E9
    */
   private void setup()
   {
     tail=head=curr=new SuperCacheNode(null);
   }

   /**
    * @return void
    * @exception
    * @author
    * @version
    * @roseuid 406B7AF70157
    */
   public void clear()
   {
     if(CachLock==true)
     {
     head.setNext(null);
     curr=tail=head;
     }
   }

   /**
    * @param Aelement
    * @return void
    * @exception
    * @author
    * @version
    * @roseuid 406B7B2A035A
    */
   public void insert(CacheReferences Aelement)
   {
     Assertion.check(curr==null,"No current element");
     if(CachLock==true)
     {
     try
     {
       SuperCacheNode temp=SuperCacheNode.get(Aelement,curr.next());
       if(temp==null)
       {
         System.out.println("高速缓存满，插入失败！");
         return;
       }
       curr.setNext(temp); //Get a free node
     }
     catch(Exception e)
     {
       System.out.println("异常，插入失败！");
     }


     if (tail==curr)
       tail=curr.next();
     }
   }

   /**
    * @param Aelement
    * @return void
    * @exception
    * @author
    * @version
    * @roseuid 406B7BA00222
    */
   public void append(CacheReferences Aelement)
   {
     if(CachLock==true)
     {
     try
     {
       SuperCacheNode temp=SuperCacheNode.get(Aelement,null);
       if(temp==null)
       {
         System.out.println("高速缓存满，插入失败！");
         return;
       }
     tail.setNext(temp);
     tail=tail.next();
     }
     catch(Exception e)
     {
       System.out.println("异常，插入失败！");
     }
     }
   }

   /**
    * @return CacheReferences
    * @exception
    * @author
    * @version
    * @roseuid 406B7BF201A5
    */
   public CacheReferences remove()
   {
     Assertion.check(isInList(),"No current element");
     if(CachLock==true)
     {
     if(!isInList()) return null;
     CacheReferences it =curr.next().GetElement();
     if(tail==curr.next()) tail=curr;
     SuperCacheNode tempptr=curr.next();
     curr.setNext(curr.next().next());
     tempptr.release();
     return it;
     }
     else return null;
   }

   /**
    * @return void
    * @exception
    * @author
    * @version
    * @roseuid 406B7C1702CE
    */
   public void setFirst()
   {
     if(CachLock==true)
     curr=head;
   }

   /**
    * @return void
    * @exception
    * @author
    * @version
    * @roseuid 406B7C2F03A9
    */
   public void next()
   {
     if(CachLock==true)
     {
     if (curr!=null) curr=curr.next();
     }
   }

   /**
    * @return int
    * @exception
    * @author
    * @version
    * @roseuid 406B7C7502CE
    */
   public int length()
   {
     if(CachLock==true)
     {
     int cnt=0;
     for(SuperCacheNode temp=head.next();temp!=null;temp=temp.next())
       cnt++;
     return cnt;
     }
     return 0;
   }

   /**
    * @param Aelement
    * @return void
    * @exception
    * @author
    * @version
    * @roseuid 406B7CBF0109
    */
   public void setValue(CacheReferences Aelement)
   {
     Assertion.check(isInList(),"No current element");
     if(CachLock==true)
     {
     curr.next().SetElement(Aelement);
     }
   }

   /**
    * @return CacheReferences
    * @exception
    * @author
    * @version
    * @roseuid 406B7D0903B8
    */
   public CacheReferences currValue()
   {
     if(CachLock==true)
     {
     if(!isInList()) return null;
     return curr.next().GetElement();
     }
     return null;
   }

   /**
    * @return boolean
    * @exception
    * @author
    * @version
    * @roseuid 406B7D330128
    */
   public boolean isEmpty()
   {
     return head.next()==null;
   }

   /**
    * @return boolean
    * @exception
    * @author
    * @version
    * @roseuid 406B7D5E01E3
    */
   public boolean isInList()
   {
     return(curr!=null)&&(curr.next()!=null);
   }

   /**
    * @return void
    * @exception
    * @author
    * @version
    * @roseuid 406B7D8E01F3
    */
   public void print()
   {
     if(isEmpty()) System.out.println("()");
     else
     {
       System.out.println("(");
         for(setFirst();isInList();next())
         { for(int i=0;i<=30;i++)
           System.out.print(currValue().GetValues()[i]+"   ");
           System.out.println();
         }
       System.out.println(")");
     }
   }

   /**
    * @return void
    * @exception
    * @author
    * @version
    * @roseuid 40700CC00170
    */
   public void prev()
   {
     if(CachLock==true)
     {
     if((curr==null)||(curr==head))
     {curr=null;
      return;
     }
     SuperCacheNode temp=head;
     while ((temp!=null)&&(temp.next()!=curr))
       temp=temp.next();
     curr=temp;
     }
   }

   /**
    * @param pos
    * @return void
    * @exception
    * @author
    * @version
    * @roseuid 4070153201BF
    */
   public void setPos(int pos)
   {
     if(CachLock==true)
     {
     curr=head;
     for(int i=0;(curr!=null)&&(i<pos);i++)
       curr=curr.next();
     }
   }

   /**
    * @return boolean
    * @exception
    * @author
    * @version
    * @roseuid 40715C320145
    */
   public boolean open()
   {
     CachLock=true;
     return CachLock;
   }

   /**
    * @return boolean
    * @exception
    * @author
    * @version
    * @roseuid 40715CCE030B
    */
   public boolean close()
   {
     CachLock=false;
     return CachLock;
   }

   /**
    * @param paraName
    * @param paraValue
    * @return int
    * @exception
    * @author
    * @version
    * @roseuid 4072135F0211
    */
   public int GetQueryCount(String paraName, String paraValue)
   {
     int location=ParseName(paraName);
     String str;
     setFirst();
     tepcn=0;
     while(isInList())
     {
       CacheReferences aRef=currValue();
       str=aRef.GetValues()[location];
       if(str==paraValue)
       {
       tepcn++;
      // aRef.GetValues();
       }
       next();
     }
     return tepcn;
   }

   /**
    * @param paraName
    * @param paraValue
    * @return String[][]
    * @exception
    * @author
    * @version
    * @roseuid 4072138E031A
    */
   public String[][] GetQueryResult(String paraName, String paraValue)
   {
     int location=ParseName(paraName);
     int cn=0;
     String str;
     String [][] relt=new String[tepcn][31];
     setFirst();
     while(isInList())
     {
       CacheReferences aRef=currValue();
       str=aRef.GetValues()[location];
       if(str==paraValue)
       {
       relt[cn]=aRef.GetValues();
       cn++;
       }
       next();
     }
     return relt;
   }

   /**
    * @param columnName
    * @return int
    * @exception
    * @author
    * @version
    * @roseuid 407219960220
    */
   public int ParseName(String columnName)
   {
     if(columnName.equals("SourceFileName"))
       return 0;
     else if(columnName.equals("CacheFileName"))
       return 1;
           else if(columnName.equals("ScreenSize"))
             return 23;
     else return 9999;
   }

   /**
    * @param paraName
    * @param paraValue
    * @return boolean
    * @exception
    * @author
    * @version
    * @roseuid 407CDA300148
    */
   public boolean delete(String paraName, String paraValue)
   {
     try
     {
       int location=ParseName(paraName);
       String str;
       setFirst();
       tepcn=0;
       while(isInList())
       {
        CacheReferences aRef=currValue();
        str=aRef.GetValues()[location];
       if(str.equals(paraValue))
        {
         remove();
        }
        else next();
       }
       return true;
     }
     catch(Exception e)
     {
       return false;
     }
   }
}