Package com.mckoi.database
Class DataTableFilter
- java.lang.Object
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- com.mckoi.database.Table
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- com.mckoi.database.AbstractDataTable
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- com.mckoi.database.DataTableFilter
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- All Implemented Interfaces:
RootTable
,TableDataSource
public class DataTableFilter extends AbstractDataTable
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
Fields Modifier and Type Field Description protected AbstractDataTable
parent
The parent DataTable object.-
Fields inherited from class com.mckoi.database.Table
DEBUG_QUERY
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Constructor Summary
Constructors Modifier Constructor Description protected
DataTableFilter(AbstractDataTable table)
The Constructor.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description int
findFieldName(Variable v)
Given a fully qualified variable field name, ie.TObject
getCellContents(int column, int row)
Returns an object that represents the information in the given cell in the table.int
getColumnCount()
Returns the number of columns in the table.Database
getDatabase()
Returns the Database context for this filtered table.DataTableDef
getDataTableDef()
Returns a DataTableDef object that defines the name of the table and the layout of the columns of the table.Variable
getResolvedVariable(int column)
Returns a fully qualified Variable object that represents the name of the column at the given index.int
getRowCount()
Returns the number of rows stored in the table.boolean
hasRootsLocked()
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.RowEnumeration
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
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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 Detail
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parent
protected AbstractDataTable parent
The parent DataTable object.
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Constructor Detail
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DataTableFilter
protected DataTableFilter(AbstractDataTable table)
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 Detail
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getDatabase
public Database 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
public int findFieldName(Variable v)
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
public Variable getResolvedVariable(int column)
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
public final TObject getCellContents(int column, int row)
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
public final RowEnumeration 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
public DataTableDef 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.
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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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