Author: elecharny
Date: Wed Jun 20 14:56:30 2012
New Revision: 1352136
URL: http://svn.apache.org/viewvc?rev=1352136&view=rev
Log:
Added a helper method
Modified:
labs/mavibot/trunk/mavibot/src/main/java/org/apache/mavibot/btree/Node.java
Modified:
labs/mavibot/trunk/mavibot/src/main/java/org/apache/mavibot/btree/Node.java
URL:
http://svn.apache.org/viewvc/labs/mavibot/trunk/mavibot/src/main/java/org/apache/mavibot/btree/Node.java?rev=1352136&r1=1352135&r2=1352136&view=diff
==============================================================================
--- labs/mavibot/trunk/mavibot/src/main/java/org/apache/mavibot/btree/Node.java
(original)
+++ labs/mavibot/trunk/mavibot/src/main/java/org/apache/mavibot/btree/Node.java
Wed Jun 20 14:56:30 2012
@@ -106,20 +106,7 @@ public class Node<K, V> extends Abstract
if ( result instanceof ModifyResult )
{
// The child has been modified.
- ModifyResult<K, V> modifyResult = (ModifyResult<K, V>)result;
-
- // Just copy the current page and update its revision
- Page<K, V> newPage = copy( revision );
-
- // Last, we update the children table of the newly created page
- // to point on the modified child
- ((Node<K, V>)newPage).children[pos] = modifyResult.modifiedPage;
-
- // We can return the result, where we update the modifiedPage,
- // to avoid the creation of a new object
- modifyResult.modifiedPage = newPage;
-
- return modifyResult;
+ return replaceChild( revision, (ModifyResult<K, V>)result, pos );
}
else
{
@@ -141,7 +128,7 @@ public class Node<K, V> extends Abstract
else
{
// The page can contain the new pivot, let's insert it
- result = addElement( revision, pivot, leftPage, rightPage, pos
);
+ result = insertChild( revision, pivot, leftPage, rightPage,
pos );
}
return result;
@@ -170,6 +157,33 @@ public class Node<K, V> extends Abstract
/**
+ * This method is used when we have to replace a child in a page when we
have
+ * found the key in the tree (the value will be changed, so we have made
+ * copies of the existing pages).
+ *
+ * @param revision The current revision
+ * @param result The modified page
+ * @param pos The position of the found key
+ * @return A modified page
+ */
+ private InsertResult<K, V> replaceChild( long revision, ModifyResult<K, V>
result, int pos )
+ {
+ // Just copy the current page and update its revision
+ Page<K, V> newPage = copy( revision );
+
+ // Last, we update the children table of the newly created page
+ // to point on the modified child
+ ((Node<K, V>)newPage).children[pos] = result.modifiedPage;
+
+ // We can return the result, where we update the modifiedPage,
+ // to avoid the creation of a new object
+ result.modifiedPage = newPage;
+
+ return result;
+ }
+
+
+ /**
* Add a new key into a copy of the current page at a given position. We
return the
* modified page. The new page will have one more key than the current
page.
*
@@ -180,7 +194,7 @@ public class Node<K, V> extends Abstract
* @param pos The position into the page
* @return The modified page with the <K,V> element added
*/
- private InsertResult<K, V> addElement( long revision, K key, Page<K, V>
leftPage, Page<K, V> rightPage, int pos )
+ private InsertResult<K, V> insertChild( long revision, K key, Page<K, V>
leftPage, Page<K, V> rightPage, int pos )
{
// First copy the current page, but add one element in the copied page
Node<K, V> newNode = new Node<K, V>( btree, revision, nbElems + 1 );
@@ -257,7 +271,7 @@ public class Node<K, V> extends Abstract
System.arraycopy( keys, pos, newLeftPage.keys, pos + 1, middle -
pos - 1 );
System.arraycopy( children, pos + 1, newLeftPage.children, pos +
2, middle - pos - 1 );
- // Copy the keys and the values in the right page
+ // Copy the keys and the children in the right page
System.arraycopy( keys, middle, newRightPage.keys, 0, middle );
System.arraycopy( children, middle, newRightPage.children, 0,
middle + 1 );
@@ -270,7 +284,7 @@ public class Node<K, V> extends Abstract
{
// A special case : the pivot will be propagated up in the tree
// The left and right pages will be spread on the two new pages
- // Copy the keys and the children up to the insertion position
+ // Copy the keys and the children up to the insertion position
(here, middle)
System.arraycopy( keys, 0, newLeftPage.keys, 0, middle );
System.arraycopy( children, 0, newLeftPage.children, 0, middle );
newLeftPage.children[middle] = leftPage;
@@ -291,7 +305,7 @@ public class Node<K, V> extends Abstract
System.arraycopy( keys, 0, newLeftPage.keys, 0, middle );
System.arraycopy( children, 0, newLeftPage.children, 0, middle + 1
);
- // Copy the keys and the values in the right page up to the pos
+ // Copy the keys and the children in the right page up to the pos
System.arraycopy( keys, middle + 1, newRightPage.keys, 0, pos -
middle - 1 );
System.arraycopy( children, middle + 1, newRightPage.children, 0,
pos - middle - 1 );
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