only need to generate index row values once per lookup iteration

git-svn-id: https://svn.code.sf.net/p/jackcess/code/jackcess/trunk@883 f203690c-595d-4dc9-a70b-905162fa7fd2

2 files changed, 61 insertions, 16 deletions

diff --git a/src/main/java/com/healthmarketscience/jackcess/impl/CursorImpl.java b/src/main/java/com/healthmarketscience/jackcess/impl/CursorImpl.java
index 89b1883..71c66e7 100644
--- a/src/main/java/com/healthmarketscience/jackcess/impl/CursorImpl.java
+++ b/src/main/java/com/healthmarketscience/jackcess/impl/CursorImpl.java
@@ -456,7 +456,8 @@ public abstract class CursorImpl implements Cursor
     throws IOException
   {
     return findAnotherRow(columnPattern, valuePattern, true, MOVE_FORWARD,
-                          _columnMatcher);
+                          _columnMatcher, 
+                          prepareSearchInfo(columnPattern, valuePattern));
   }
 
   public boolean findNextRow(Column columnPattern, Object valuePattern)
@@ -469,12 +470,13 @@ public abstract class CursorImpl implements Cursor
     throws IOException
   {
     return findAnotherRow(columnPattern, valuePattern, false, MOVE_FORWARD,
-                          _columnMatcher);
+                          _columnMatcher, 
+                          prepareSearchInfo(columnPattern, valuePattern));
   }
   
   protected boolean findAnotherRow(ColumnImpl columnPattern, Object valuePattern,
                                    boolean reset, boolean moveForward,
-                                   ColumnMatcher columnMatcher)
+                                   ColumnMatcher columnMatcher, Object searchInfo)
     throws IOException
   {
     PositionImpl curPos = _curPos;
@@ -485,7 +487,7 @@ public abstract class CursorImpl implements Cursor
         reset(moveForward);
       }
       found = findAnotherRowImpl(columnPattern, valuePattern, moveForward,
-                                 columnMatcher, null);
+                                 columnMatcher, searchInfo);
       return found;
     } finally {
       if(!found) {
@@ -500,18 +502,20 @@ public abstract class CursorImpl implements Cursor
   
   public boolean findFirstRow(Map<String,?> rowPattern) throws IOException
   {
-    return findAnotherRow(rowPattern, true, MOVE_FORWARD, _columnMatcher);
+    return findAnotherRow(rowPattern, true, MOVE_FORWARD, _columnMatcher,
+                          prepareSearchInfo(rowPattern));
   }
 
   public boolean findNextRow(Map<String,?> rowPattern)
     throws IOException
   {
-    return findAnotherRow(rowPattern, false, MOVE_FORWARD, _columnMatcher);
+    return findAnotherRow(rowPattern, false, MOVE_FORWARD, _columnMatcher,
+                          prepareSearchInfo(rowPattern));
   }
 
   protected boolean findAnotherRow(Map<String,?> rowPattern, boolean reset,
                                    boolean moveForward, 
-                                   ColumnMatcher columnMatcher)
+                                   ColumnMatcher columnMatcher, Object searchInfo)
     throws IOException
   {
     PositionImpl curPos = _curPos;
@@ -521,7 +525,8 @@ public abstract class CursorImpl implements Cursor
       if(reset) {
         reset(moveForward);
       }
-      found = findAnotherRowImpl(rowPattern, moveForward, columnMatcher, null);
+      found = findAnotherRowImpl(rowPattern, moveForward, columnMatcher,        
+                                 searchInfo);
       return found;
     } finally {
       if(!found) {
@@ -641,6 +646,24 @@ public abstract class CursorImpl implements Cursor
   }  
 
   /**
+   * Called before a search commences to allow for search specific data to be
+   * generated (which is cached for re-use by the iterators).
+   */
+  protected Object prepareSearchInfo(ColumnImpl columnPattern, Object valuePattern)
+  {
+    return null;
+  }
+
+  /**
+   * Called before a search commences to allow for search specific data to be
+   * generated (which is cached for re-use by the iterators).
+   */
+  protected Object prepareSearchInfo(Map<String,?> rowPattern)
+  {
+    return null;
+  }
+
+  /**
    * Called by findAnotherRowImpl to determine if the search should continue
    * after finding a row which does not match the current pattern.
    */
@@ -857,6 +880,7 @@ public abstract class CursorImpl implements Cursor
   {
     private final ColumnImpl _columnPattern;
     private final Object _valuePattern;
+    private final Object _searchInfo;
     
     private ColumnMatchIterator(Collection<String> columnNames,
                                 ColumnImpl columnPattern, Object valuePattern,
@@ -866,12 +890,13 @@ public abstract class CursorImpl implements Cursor
       super(columnNames, reset, moveForward, columnMatcher);
       _columnPattern = columnPattern;
       _valuePattern = valuePattern;
+      _searchInfo = prepareSearchInfo(columnPattern, valuePattern);
     }
 
     @Override
     protected boolean findNext() throws IOException {
       return findAnotherRow(_columnPattern, _valuePattern, false, _moveForward,
-                            _colMatcher);
+                            _colMatcher, _searchInfo);
     }
   }
 
@@ -882,6 +907,7 @@ public abstract class CursorImpl implements Cursor
   private final class RowMatchIterator extends BaseIterator
   {
     private final Map<String,?> _rowPattern;
+    private final Object _searchInfo;
     
     private RowMatchIterator(Collection<String> columnNames,
                              Map<String,?> rowPattern,
@@ -890,11 +916,13 @@ public abstract class CursorImpl implements Cursor
     {
       super(columnNames, reset, moveForward, columnMatcher);
       _rowPattern = rowPattern;
+      _searchInfo = prepareSearchInfo(rowPattern);
     }
 
     @Override
     protected boolean findNext() throws IOException {
-      return findAnotherRow(_rowPattern, false, _moveForward, _colMatcher);
+      return findAnotherRow(_rowPattern, false, _moveForward, _colMatcher,
+                            _searchInfo);
     }
   }
 
diff --git a/src/main/java/com/healthmarketscience/jackcess/impl/IndexCursorImpl.java b/src/main/java/com/healthmarketscience/jackcess/impl/IndexCursorImpl.java
index 4b8830a..479aa4b 100644
--- a/src/main/java/com/healthmarketscience/jackcess/impl/IndexCursorImpl.java
+++ b/src/main/java/com/healthmarketscience/jackcess/impl/IndexCursorImpl.java
@@ -249,9 +249,7 @@ public class IndexCursorImpl extends CursorImpl implements IndexCursor
       ColumnMatcher columnMatcher, Object searchInfo)
     throws IOException
   {
-    // searching for the first match
-    Object[] rowValues = _entryCursor.getIndexData().constructIndexRow(
-        columnPattern.getName(), valuePattern);
+    Object[] rowValues = (Object[])searchInfo;
 
     if((rowValues == null) || !isAtBeginning(moveForward)) {
       // use the default table scan if we don't have index data or we are
@@ -300,9 +298,7 @@ public class IndexCursorImpl extends CursorImpl implements IndexCursor
       ColumnMatcher columnMatcher, Object searchInfo)
     throws IOException
   {
-    // searching for the first match
-    IndexData indexData = _entryCursor.getIndexData();
-    Object[] rowValues = indexData.constructIndexRow(rowPattern);
+    Object[] rowValues = (Object[])searchInfo;
 
     if((rowValues == null) || !isAtBeginning(moveForward)) {
       // use the default table scan if we don't have index data or we are
@@ -318,6 +314,7 @@ public class IndexCursorImpl extends CursorImpl implements IndexCursor
     }
 
     // find actual matching row
+    IndexData indexData = _entryCursor.getIndexData();
     Map<String,?> indexRowPattern = null;
     if(rowPattern.size() == indexData.getColumns().size()) {
       // the rowPattern matches our index columns exactly, so we can
@@ -391,13 +388,33 @@ public class IndexCursorImpl extends CursorImpl implements IndexCursor
   }
 
   @Override
+  protected Object prepareSearchInfo(ColumnImpl columnPattern, Object valuePattern)
+  {
+    // attempt to generate a lookup row for this index
+    return _entryCursor.getIndexData().constructIndexRow(
+        columnPattern.getName(), valuePattern);
+  }
+
+  @Override
+  protected Object prepareSearchInfo(Map<String,?> rowPattern)
+  {
+    // attempt to generate a lookup row for this index
+    return _entryCursor.getIndexData().constructIndexRow(rowPattern);
+  }
+
+  @Override
   protected boolean keepSearching(ColumnMatcher columnMatcher, 
                                   Object searchInfo) 
     throws IOException
   {
     if(searchInfo instanceof Object[]) {
+      // if we have a lookup row for this index, then we only need to continue
+      // searching while we are looking at rows which match the index lookup
+      // value(s).  once we move past those rows, no other rows could possibly
+      // match.
       return currentRowMatchesEntryImpl((Object[])searchInfo, columnMatcher);
     }
+    // we are doing a full table scan
     return true;
   }