tim/prune/data/FieldList.java

   1 package tim.prune.data;
   2
   3 /**
   4  * Class to hold an ordered list of fields
   5  * to match the value list in a data point
   6  */
   7 public class FieldList
   8 {
   9         /** Array of Field objects making the list */
  10         private Field[] _fieldArray;
  11
  12
  13         /**
  14          * Constructor for an empty field list
  15          */
  16         public FieldList()
  17         {
  18                 _fieldArray = new Field[0];
  19         }
  20
  21         /**
  22          * Constructor for a given number of empty fields
  23          * @param inNumFields
  24          */
  25         public FieldList(int inNumFields)
  26         {
  27                 if (inNumFields < 0) inNumFields = 0;
  28                 _fieldArray = new Field[inNumFields];
  29         }
  30
  31         /**
  32          * Constructor giving array of Field objects
  33          * @param inFieldArray array of Field objects
  34          */
  35         public FieldList(Field[] inFieldArray)
  36         {
  37                 if (inFieldArray == null || inFieldArray.length == 0)
  38                 {
  39                         _fieldArray = new Field[0];
  40                 }
  41                 else
  42                 {
  43                         _fieldArray = new Field[inFieldArray.length];
  44                         System.arraycopy(inFieldArray, 0, _fieldArray, 0, inFieldArray.length);
  45                 }
  46         }
  47
  48         /**
  49          * Get the index of the given field
  50          * @param inField field to look for
  51          * @return index number of the field starting at zero
  52          */
  53         public int getFieldIndex(Field inField)
  54         {
  55                 if (inField == null) return -1;
  56                 for (int f=0; f<_fieldArray.length; f++)
  57                 {
  58                         if (_fieldArray[f] != null && _fieldArray[f].equals(inField))
  59                                 return f;
  60                 }
  61                 return -1;
  62         }
  63
  64
  65         /**
  66          * Check whether the FieldList contains the given Field object
  67          * @param inField Field to check
  68          * @return true if the FieldList contains the given field
  69          */
  70         public boolean contains(Field inField)
  71         {
  72                 return (getFieldIndex(inField) >= 0);
  73         }
  74
  75
  76         /**
  77          * @return number of fields in list
  78          */
  79         public int getNumFields()
  80         {
  81                 if (_fieldArray == null) return 0;
  82                 return _fieldArray.length;
  83         }
  84
  85
  86         /**
  87          * Get the specified Field object
  88          * @param inIndex index to retrieve
  89          * @return Field object
  90          */
  91         public Field getField(int inIndex)
  92         {
  93                 if (_fieldArray == null || inIndex < 0 || inIndex >= _fieldArray.length)
  94                 {
  95                         return null;
  96                 }
  97                 return _fieldArray[inIndex];
  98         }
  99
 100
 101         /**
 102          * Merge this list with a second list, giving a superset
 103          * @param inOtherList other FieldList object to merge
 104          * @return Merged FieldList object
 105          */
 106         public FieldList merge(FieldList inOtherList)
 107         {
 108                 // count number of fields
 109                 int totalFields = _fieldArray.length;
 110                 for (int f=0; f<inOtherList._fieldArray.length; f++)
 111                 {
 112                         if (inOtherList._fieldArray[f] != null && !contains(inOtherList._fieldArray[f]))
 113                         {
 114                                 totalFields++;
 115                         }
 116                 }
 117                 FieldList list = new FieldList(totalFields);
 118                 // copy these fields into array
 119                 System.arraycopy(_fieldArray, 0, list._fieldArray, 0, _fieldArray.length);
 120                 // copy additional fields from other array if any
 121                 if (totalFields > _fieldArray.length)
 122                 {
 123                         int fieldCounter = _fieldArray.length;
 124                         for (int f=0; f<inOtherList._fieldArray.length; f++)
 125                         {
 126                                 if (inOtherList._fieldArray[f] != null && !contains(inOtherList._fieldArray[f]))
 127                                 {
 128                                         list._fieldArray[fieldCounter] = inOtherList._fieldArray[f];
 129                                         fieldCounter++;
 130                                 }
 131                         }
 132                 }
 133                 // return the merged list
 134                 return list;
 135         }
 136
 137
 138         /**
 139          * Extend the field list to include the specified field
 140          * @param inField Field to add
 141          * @return new index of added Field
 142          */
 143         public int extendList(Field inField)
 144         {
 145                 // See if field is already in list
 146                 int currIndex = getFieldIndex(inField);
 147                 if (currIndex >= 0) return currIndex;
 148                 // Need to extend - increase array size
 149                 int oldNumFields = _fieldArray.length;
 150                 Field[] fields = new Field[oldNumFields + 1];
 151                 System.arraycopy(_fieldArray, 0, fields, 0, oldNumFields);
 152                 _fieldArray = fields;
 153                 // Add new field and return index
 154                 _fieldArray[oldNumFields] = inField;
 155                 return oldNumFields;
 156         }
 157
 158
 159         /**
 160          * Convert to String for debug
 161          */
 162         public String toString()
 163         {
 164                 StringBuffer buffer = new StringBuffer();
 165                 buffer.append('(');
 166                 for (int i=0; i<_fieldArray.length; i++)
 167                 {
 168                         buffer.append(_fieldArray[i].getName()).append(',');
 169                 }
 170                 buffer.append(')');
 171                 return buffer.toString();
 172         }
 173 }