source/mir/storage/store/StoreContainer.java

   1 package mir.storage.store;
   2
   3 /**
   4  * Title:         StoreContainer
   5  *
   6  * Description:   This is the bucket object for one type of StorableObjects,
   7  *                mainy a linked list of StoreIdenfiers. On use or creation
   8  *                an object stored in StoreIdentifier is put to head of the
   9  *                list. if maximum size of the list is reached, the
  10  *                StoreIdentifier at the end of the list is released.
  11  *
  12  * Copyright:     Copyright (c) 2002
  13  * Company:       indy
  14  * @author        //rk
  15  * @version 1.0
  16  */
  17
  18 import java.util.*;
  19 import mir.misc.Logfile;
  20
  21 public class StoreContainer {
  22
  23         private final static int    DEFAULT_SIZE=10;
  24         private static Logfile      storeLog;
  25         private static int          uniqueCounter=10000;
  26
  27         private LinkedList          container;
  28         private StoreContainerType  stocType;
  29         private int                 maxSize=DEFAULT_SIZE;
  30         private int                 uniqueId;
  31
  32         private StoreContainer() {};
  33
  34         public StoreContainer(StoreContainerType stoc_type) {
  35                 this.uniqueId=++uniqueCounter;
  36                 this.stocType=stoc_type;
  37                 this.container=new LinkedList();
  38         }
  39
  40         public StoreContainer(StoreContainerType stoc_type, int maxSize) {
  41                 this();
  42                 this.maxSize=maxSize;
  43         }
  44
  45         public StorableObject use(StoreIdentifier sid) {
  46                 // find sid in LinkedList or die
  47                 // move sid to head of linked list
  48                 // return reference on object
  49                 return null;
  50         }
  51
  52         public boolean has(StoreIdentifier sid) {
  53                 return true; // yes yes
  54         }
  55
  56         public void add(StoreIdentifier sid) {
  57                 if ( sid != null && sid.hasReference() ) {
  58                         //if ( has(sid) )
  59                         //      moveToHead(sid);
  60                         //else
  61                                 container.addFirst(sid);
  62                 }
  63                 // add to head of linkedlist, if size is exceded throw away tail until
  64                 // size ok.
  65         }
  66
  67         /**
  68          *  Method:       invalidate(StorableObject sto)
  69          *  Description:  finds @see StorableObject, propagates invalidation to
  70          *                @see StoreIdentifier and removes StoreIdentifier from
  71          *                list.
  72          */
  73         public void invalidate(StorableObject sto) {
  74                 if (sto!=null) {
  75                         StoreIdentifier sid = sto.getStoreIdentifier();
  76                         if (sid!=null) {
  77                                 if ( container.contains(sid) ) {
  78                                         sid.invalidate();
  79                                         container.remove(sid);
  80                                 }
  81                         }
  82                 }
  83         }
  84
  85         /**
  86          *  Method:       setSize
  87          *  Description:  readjusts StoreContainer size to value.
  88          *
  89          */
  90         public void setSize(int size) {
  91                 if (size <0) return;
  92     shrinkToSize(size);
  93                 this.maxSize=size;
  94         }
  95
  96         private void shrink() {
  97                 shrinkToSize(maxSize);
  98         }
  99
 100   private void shrinkToSize(int size) {
 101     if ( size<maxSize && size < container.size() ) {
 102                         // shrink
 103                         while (size < container.size() ) {
 104                                 StoreIdentifier sid = (StoreIdentifier)container.getLast();
 105                                 sid.release();
 106                                 container.remove(sid);
 107                         }
 108                 }
 109   }
 110
 111         /**
 112          *  Method:       toString()
 113          *  Description:  gives out statistical Information, viewable via
 114          *                @see ServletStoreInfo.
 115          *
 116          *  @return       String
 117          */
 118         public String toString() {
 119                 StringBuffer sb = new StringBuffer("StoreContainer id: ");
 120                 sb.append(uniqueId).append(" for ");
 121                 sb.append(stocType.toString()).append(" // Current/Max size: ");
 122                 sb.append(container.size()).append(" / ");
 123                 sb.append(maxSize).append("\n");
 124                 /** @todo list members ? */
 125                 return sb.toString();
 126         }
 127
 128 }