com.mckoi.database

Class CollatedBaseSearch

java.lang.Object

com.mckoi.database.SelectableScheme

com.mckoi.database.CollatedBaseSearch

Direct Known Subclasses:

InsertSearch

public abstract class CollatedBaseSearch
extends SelectableScheme

An implementation of SelectableScheme that is based on some collated set of data. This can be used to implement more advanced types of selectable schemes based on presistant indexes (see InsertSearch).

The default implementation maintains no state,

Derived classes are required to implement 'copy', 'searchFirst' and 'searchLast' methods. With these basic methods, a selectable scheme can be generated provided the column is sorted in ascending order (value of row i is <= value of row i+1). Overwrite 'firstInCollationOrder', 'lastInCollationOrder' and 'addRangeToSet' methods for non sorted underlying sets.

Assumptions - the underlying column is sorted low to high (value of row i is <= value of row i+1).

Author:

Tobias Downer

Field Summary

Fields inherited from class com.mckoi.database.SelectableScheme

EMPTY_LIST, ONE_LIST

Constructor Summary

Constructors

Constructor and Description
CollatedBaseSearch(TableDataSource table, int column) The Constructor.

Method Summary

Modifier and Type	Method and Description
protected IntegerVector	addRangeToSet(int start, int end, IntegerVector ivec) Adds the set indexes to the list that represent the range of values between the start (inclusive) and end offset (inclusive) given.
void	dispose() Disposes and invalidates the BlindSearch.
protected TObject	firstInCollationOrder() Returns the first value of this column (in collated order).
void	insert(int row) This scheme doesn't take any notice of insertions or removals.
protected TObject	lastInCollationOrder() Returns the last value of this column (in collated order).
void	readFrom(InputStream in) Reads the entire state of the scheme from the input stream.
void	remove(int row) This scheme doesn't take any notice of insertions or removals.
protected abstract int	searchFirst(TObject val) Finds the position in the collated set of the first value in the column equal to the given value.
protected abstract int	searchLast(TObject val) Finds the position in the collated set of the last value in the column equal to the given value.
IntegerVector	selectAll() These are the select operations that are the main purpose of the scheme.
IntegerVector	selectRange(SelectableRange range) Selects the given range of values from this index.
IntegerVector	selectRange(SelectableRange[] ranges) Selects a set of ranges from this index.
protected int	setSize() The size of the set (the number of rows in this column).
void	writeTo(OutputStream out) Writes the entire state of the scheme to the output stream.

Methods inherited from class com.mckoi.database.SelectableScheme

copy, Debug, getCellContents, getColumn, getSubsetScheme, getSystem, getTable, internalOrderIndexSet, isImmutable, selectAllNonNull, selectBetween, selectEqual, selectFirst, selectGreater, selectGreaterOrEqual, selectLast, selectLess, selectLessOrEqual, selectNotEqual, selectNotFirst, selectNotLast, setImmutable, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

CollatedBaseSearch

public CollatedBaseSearch(TableDataSource table,
                          int column)

The Constructor.

Method Detail

insert

public void insert(int row)

This scheme doesn't take any notice of insertions or removals.

remove

public void remove(int row)

This scheme doesn't take any notice of insertions or removals.

readFrom

public void readFrom(InputStream in)
              throws IOException

Reads the entire state of the scheme from the input stream. This is a trivial case for BlindSearch which doesn't require any data to be stored.

Specified by:

readFrom in class SelectableScheme

Throws:

IOException

writeTo

public void writeTo(OutputStream out)
             throws IOException

Writes the entire state of the scheme to the output stream. This is a trivial case for BlindSearch which doesn't require any data to be stored.

Specified by:

writeTo in class SelectableScheme

Throws:

IOException

dispose

public void dispose()

Disposes and invalidates the BlindSearch.

Specified by:

dispose in class SelectableScheme

searchFirst

protected abstract int searchFirst(TObject val)

Finds the position in the collated set of the first value in the column equal to the given value. If the value is not to be found in the column, it returns -(insert_position + 1).

searchLast

protected abstract int searchLast(TObject val)

Finds the position in the collated set of the last value in the column equal to the given value. If the value is not to be found in the column, it returns -(insert_position + 1).

setSize

protected int setSize()

The size of the set (the number of rows in this column).

firstInCollationOrder

protected TObject firstInCollationOrder()

Returns the first value of this column (in collated order). For example, if the column contains (1, 4, 8} then '1' is returned.

lastInCollationOrder

protected TObject lastInCollationOrder()

Returns the last value of this column (in collated order). For example, if the column contains (1, 4, 8} then '8' is returned.

addRangeToSet

protected IntegerVector addRangeToSet(int start,
                                      int end,
                                      IntegerVector ivec)

Adds the set indexes to the list that represent the range of values between the start (inclusive) and end offset (inclusive) given.

selectAll

public IntegerVector selectAll()

Description copied from class: SelectableScheme

These are the select operations that are the main purpose of the scheme. They retrieve the given information from the set. Different schemes will have varying performance on different types of data sets. The select operations must *always* return a resultant row set that is sorted from lowest to highest.

Overrides:

selectAll in class SelectableScheme

selectRange

public IntegerVector selectRange(SelectableRange range)

Description copied from class: SelectableScheme

Selects the given range of values from this index. The SelectableRange must contain a 'start' value that compares <= to the 'end' value.

This must guarentee that the returned set is sorted from lowest to highest value.

selectRange

public IntegerVector selectRange(SelectableRange[] ranges)

Description copied from class: SelectableScheme

Selects a set of ranges from this index. The ranges must not overlap and each range must contain a 'start' value that compares <= to the 'end' value. Every range in the array must represent a range that's lower than the preceeding range (if it exists).

If the above rules are enforced (as they must be) then this method will return a set that is sorted from lowest to highest value.

This must guarentee that the returned set is sorted from lowest to highest value.