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Java > Open Source Codes > com > daffodilwoods > daffodildb > server > datasystem > btree > BTreeNavigatorCurrent


1 package com.daffodilwoods.daffodildb.server.datasystem.btree;
2
3 import com.daffodilwoods.database.resource.DException;
4 import com.daffodilwoods.daffodildb.server.datasystem.interfaces._Index;
5 import com.daffodilwoods.database.utility.P;
6 import com.daffodilwoods.daffodildb.utils.BufferRange;
7
8 public class BTreeNavigatorCurrent extends BTreeNavigator{
9
10   public BTreeNavigatorCurrent(_Index btree){
11     super(btree);
12   }
13
14   public Object JavaDoc getCurrentKey() throws DException{
15      BTreeKey currentKey2 = (BTreeKey)currentKey;
16      return status != 0 ? null : currentKey2;
17  }
18
19    public Object JavaDoc getKey()throws DException{
20      BTreeKey currentKey2 = (BTreeKey)currentKey;
21
22      if(status != 0)
23            new Exception JavaDoc("CHECK THE CASE").printStackTrace();
24        Object JavaDoc oldValue = currentKey2.getValue();
25        BTreeElement element = currentKey2.getNode().getElement(currentKey2.getPosition(),null);
26        Object JavaDoc newValue = element.getValue();
27        if(oldValue.equals(newValue)){
28           return element.getKey();
29        }
30        else
31          throw StaticExceptions.RECORD_DELETED_EXCEPTION ;
32    }
33
34    public Object JavaDoc getValue()throws DException{
35      BTreeKey currentKey2 = (BTreeKey)currentKey;
36      if(status != 0)
37        new Exception JavaDoc("CHECK THE CASE " + currentKey2.getNode() + " position " +
38                      currentKey2.getPosition()).printStackTrace();
39      return currentKey2.getValue();
40   }
41   public Object JavaDoc getColumnValues(int columnIndex) throws DException{
42       int[] columns = btree.getIndexInformation().getColumnIndexes();
43       int pos = P.indexOf(columns,columnIndex);
44       Object JavaDoc value = currentKey.getKey();
45       if(pos == -1)
46           throw StaticExceptions.NOT_POSSIBLE;
47       return columns.length == 1 ? value : ((Object JavaDoc[])value)[pos];
48   }
49
50   public Object JavaDoc getColumnValues(int[] columnIndexes) throws DException{
51       int[] columns = btree.getIndexInformation().getColumnIndexes();
52       int[] indexes = null;
53       if((indexes = canGive(columns,columnIndexes)) == null)
54           throw StaticExceptions.NOT_POSSIBLE;
55       Object JavaDoc[] value = (Object JavaDoc[])currentKey.getKey();
56       BufferRange[] values = new BufferRange[columnIndexes.length];
57       for(int i = 0; i < columnIndexes.length; i++) {
58           values[i] = (BufferRange)value[indexes[i]];
59       }
60       return values;
61   }
62
63   private int[] canGive(int[] btreeColumns,int[] columns) {
64       if(columns.length > btreeColumns.length )
65           return null;
66       int[] positions = new int[columns.length];
67       for(int i = 0; i < columns.length; i++) {
68           if((positions[i] = P.indexOf(btreeColumns,columns[i])) == -1){
69               return null;
70           }
71       }
72       return positions;
73   }
74
75   public void move(Object JavaDoc key)throws DException{
76    super.move(key);
77    status = (((BTreeKey)currentKey).getNode() == null || ((BTreeKey)currentKey).getPosition() == 0 ) ? -1 : 0;
78   }
79
80   /*
81   private String showArray(int[] array) {
82       StringBuffer sb = new StringBuffer();
83       for (int i = 0; i < array.length; i++) {
84           sb.append(array[i]);
85           sb.append(",");
86       }
87       sb.deleteCharAt(sb.length()-1);
88       return sb.toString();
89   }
90 */
91 }
92
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