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java.lang.Objectorg.apache.derby.impl.store.access.btree.BranchRow
Implements row which is stored in the branch pages of a btree. A non-suffix compressed branch row contains all of the columns of the leaf rows of a btree and contains an additional field at the end. The extra field of a branch row in a branch page at level N, is the child page field pointing the page at level N-1 which has keys which follow or equal the branch row entry. There are 3 ways to use this class to produce a branch row: createEmptyTemplate() creates a empty row template createBranchRowFromOldBranchRow() creates a new row with reference to an old branch row. createBranchRowFromOldLeafRow() creates a new row with reference to an old leaf row.
Field Summary | |
private DataValueDescriptor[] |
branchrow
The array of object to be used as the row. |
static long |
DUMMY_PAGE_NUMBER
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Constructor Summary | |
private |
BranchRow()
Constuctor for creating an "empty" BranchRow template, suitable for reading in a branchRow from disk. |
private |
BranchRow(BTree btree)
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Method Summary | |
BranchRow |
createBranchRowFromOldBranchRow(long childpageno)
Create a new branch row, given a old branch row and a new child page. |
static BranchRow |
createBranchRowFromOldLeafRow(DataValueDescriptor[] leafrow,
long childpageno)
Create a new branch row, given a old leaf row and a new child page. |
static BranchRow |
createEmptyTemplate(BTree btree)
Create an empty branch row template suitable for reading branch rows in from disk. |
private SQLLongint |
getChildPage()
Accessor for the child page field of the branch row. |
protected DataValueDescriptor[] |
getRow()
Return the branch row. |
protected void |
setPageNumber(long page_number)
Set the page number field of the branch row to a new value. |
java.lang.String |
toString()
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Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Field Detail |
public static final long DUMMY_PAGE_NUMBER
private DataValueDescriptor[] branchrow
Constructor Detail |
private BranchRow()
private BranchRow(BTree btree) throws StandardException
Method Detail |
private SQLLongint getChildPage()
public static BranchRow createEmptyTemplate(BTree btree) throws StandardException
StandardException
- Standard exception policy.public BranchRow createBranchRowFromOldBranchRow(long childpageno)
public static BranchRow createBranchRowFromOldLeafRow(DataValueDescriptor[] leafrow, long childpageno)
protected DataValueDescriptor[] getRow()
Return the DataValueDescriptor array that represents the branch row, for use in raw store calls to fetch, insert, and update.
protected void setPageNumber(long page_number)
page_number
- the new page number.public java.lang.String toString()
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Built on Tue 2006-10-10 19:23:47+0200, from revision exported | |||||||||
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