Package com.mckoi.database
Class DataTableFilter
java.lang.Object
com.mckoi.database.Table
com.mckoi.database.AbstractDataTable
com.mckoi.database.DataTableFilter
- All Implemented Interfaces:
RootTable
,TableDataSource
This object sits on top of a DataTable object filtering out certain types
of calls. We could use this object to implement a ReferenceTable which
can be used to declare a new table name with a DataTable type. We also
use this object to implement a filter for column removals.
- Author:
- Tobias Downer
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Field Summary
FieldsFields inherited from class com.mckoi.database.Table
DEBUG_QUERY
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Constructor Summary
ConstructorsModifierConstructorDescriptionprotected
DataTableFilter
(AbstractDataTable table) The Constructor. -
Method Summary
Modifier and TypeMethodDescriptionint
Given a fully qualified variable field name, ie.final TObject
getCellContents
(int column, int row) Returns an object that represents the information in the given cell in the table.int
Returns the number of columns in the table.Returns the Database context for this filtered table.Returns a DataTableDef object that defines the name of the table and the layout of the columns of the table.getResolvedVariable
(int column) Returns a fully qualified Variable object that represents the name of the column at the given index.final int
Returns the number of rows stored in the table.boolean
Returns true if the table has its row roots locked (via the lockRoot(int) method.void
lockRoot
(int lock_key) Locks the root table(s) of this table so that it is impossible to overwrite the underlying rows that may appear in this table.final RowEnumeration
Returns an Enumeration of the rows in this table.void
unlockRoot
(int lock_key) Unlocks the root tables so that the underlying rows may once again be used if they are not locked and have been removed.Methods inherited from class com.mckoi.database.AbstractDataTable
getTableName, toString, typeEquals
Methods inherited from class com.mckoi.database.Table
all, allColumnMatchesValue, any, columnContainsCell, columnContainsValue, columnMatchesValue, columnMerge, compareCells, Debug, distinct, distinct, dumpTo, emptySelect, exhaustiveSelect, fastFindFieldName, getColumnDefAt, getColumnScheme, getFirstCellContent, getFirstCellContent, getLastCellContent, getLastCellContent, getSingleCellContent, getSingleCellContent, getSystem, getTableAccessState, getTTypeForColumn, getTTypeForColumn, join, orderByColumn, orderByColumn, orderByColumn, orderByColumns, orderedRowList, outside, printGraph, rangeSelect, selectAll, selectAll, selectFirst, selectLast, selectRange, selectRest, simpleJoin, simpleSelect, singleRowSelect, toMap, union
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Field Details
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parent
The parent DataTable object.
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Constructor Details
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DataTableFilter
The Constructor. A filter can only sit on top of a DataTable or DataTableFilter table. ISSUE: we could make an interface for this. This is a bit of a hack.
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Method Details
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getDatabase
Returns the Database context for this filtered table.- Specified by:
getDatabase
in classTable
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getColumnCount
public int getColumnCount()Returns the number of columns in the table.- Specified by:
getColumnCount
in classTable
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getRowCount
public final int getRowCount()Returns the number of rows stored in the table.- Specified by:
getRowCount
in interfaceTableDataSource
- Specified by:
getRowCount
in classTable
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findFieldName
Given a fully qualified variable field name, ie. 'APP.CUSTOMER.CUSTOMERID' this will return the column number the field is at. Returns -1 if the field does not exist in the table.- Specified by:
findFieldName
in classTable
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getResolvedVariable
Returns a fully qualified Variable object that represents the name of the column at the given index. For example, new Variable(new TableName("APP", "CUSTOMER"), "ID")- Specified by:
getResolvedVariable
in classTable
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getCellContents
Returns an object that represents the information in the given cell in the table. This will generally be an expensive algorithm, so calls to it should be kept to a minimum. Note that the offset between two rows is not necessarily 1.- Specified by:
getCellContents
in interfaceTableDataSource
- Specified by:
getCellContents
in classTable
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rowEnumeration
Returns an Enumeration of the rows in this table. The Enumeration is a fast way of retrieving consequtive rows in the table.- Specified by:
rowEnumeration
in interfaceTableDataSource
- Specified by:
rowEnumeration
in classTable
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getDataTableDef
Returns a DataTableDef object that defines the name of the table and the layout of the columns of the table. Note that for tables that are joined with other tables, the table name and schema for this object become mangled. For example, a table called 'PERSON' joined with a table called 'MUSIC' becomes a table called 'PERSON#MUSIC' in a null schema.- Specified by:
getDataTableDef
in interfaceTableDataSource
- Specified by:
getDataTableDef
in classTable
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lockRoot
public void lockRoot(int lock_key) Locks the root table(s) of this table so that it is impossible to overwrite the underlying rows that may appear in this table. This is used when cells in the table need to be accessed 'outside' the lock. So we may have late access to cells in the table. 'lock_key' is a given key that will also unlock the root table(s). NOTE: This is nothing to do with the 'LockingMechanism' object. -
unlockRoot
public void unlockRoot(int lock_key) Unlocks the root tables so that the underlying rows may once again be used if they are not locked and have been removed. This should be called some time after the rows have been locked.- Specified by:
unlockRoot
in classTable
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hasRootsLocked
public boolean hasRootsLocked()Returns true if the table has its row roots locked (via the lockRoot(int) method.- Specified by:
hasRootsLocked
in classTable
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