Package uk.ac.starlink.table
Class ConcatStarTable
- java.lang.Object
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- uk.ac.starlink.table.WrapperStarTable
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- uk.ac.starlink.table.ConcatStarTable
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- All Implemented Interfaces:
StarTable
public class ConcatStarTable extends WrapperStarTable
StarTable implementation which concatenates several tables together top-to-bottom. A (possibly blank) metadata table is supplied to define the column and table metadata for the result, and other data tables are added on one way or another, depending which constructor is used. The columns of each data table must be compatible with the columns of the metadata table, or the the data will not be included.- Since:
- 29 Mar 2004
- Author:
- Mark Taylor
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Field Summary
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Fields inherited from class uk.ac.starlink.table.WrapperStarTable
baseTable
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Constructor Summary
Constructors Constructor Description ConcatStarTable(StarTable meta, java.util.Iterator tableIt)
Constructs a concatenated table from a metadata table and an iterator over data-bearing tables.ConcatStarTable(StarTable meta, StarTable[] tables)
Constructs a concatenated table from a metadata table and an array of data-bearing tables.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description static ColumnInfo[]
extendColumnTypes(ColumnInfo[] colInfos, StarTable[] tables)
Assembles column metadata objects which are compatible between multiple tables.java.lang.Object
getCell(long irow, int icol)
Returns the contents of a given table cell.java.lang.Object[]
getRow(long irow)
Returns the contents of a given table row.long
getRowCount()
Returns the number of rows in this table, if known.RowSequence
getRowSequence()
Returns an object which can iterate over all the rows in the table sequentially.boolean
isRandom()
Indicates whether random access is provided by this table.-
Methods inherited from class uk.ac.starlink.table.WrapperStarTable
checkedLongToInt, getBaseTable, getColumnAuxDataInfos, getColumnCount, getColumnInfo, getName, getParameterByName, getParameters, getURL, setName, setParameter, setURL, toString
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Constructor Detail
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ConcatStarTable
public ConcatStarTable(StarTable meta, java.util.Iterator tableIt)
Constructs a concatenated table from a metadata table and an iterator over data-bearing tables. If any of the tables supplied by the iterator are incompatible with the metadata inmeta
a warning message is issued through the logging system and its rows are ignored.- Parameters:
meta
- table supplying column and table metadata for this one; its row count is ignored and its data is never readtableIt
- iterator over constituentStarTable
s which taken in sequence supply the row data for this one
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ConcatStarTable
public ConcatStarTable(StarTable meta, StarTable[] tables) throws java.io.IOException
Constructs a concatenated table from a metadata table and an array of data-bearing tables. If any oftables
are incompatible with the metadata inmeta
an IOException is thrown.- Parameters:
meta
- table supplying column and table metadata for this one; its row count is ignored and its data is never readtables
- array of tables which taken in sequence supply the row data for this one- Throws:
java.io.IOException
- if any oftables
are not compatible withmeta
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Method Detail
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getRowCount
public long getRowCount()
Description copied from interface:StarTable
Returns the number of rows in this table, if known. If the number of rows cannot be (easily) determined, a value of -1 will be returned.- Specified by:
getRowCount
in interfaceStarTable
- Overrides:
getRowCount
in classWrapperStarTable
- Returns:
- the number of rows, or -1
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getCell
public java.lang.Object getCell(long irow, int icol) throws java.io.IOException
Description copied from interface:StarTable
Returns the contents of a given table cell. The class of the returned object should be the same as, or a subclass of, the class returned by getColumnInfo(icol).getContentClass().- Specified by:
getCell
in interfaceStarTable
- Overrides:
getCell
in classWrapperStarTable
- Parameters:
irow
- the index of the cell's rowicol
- the index of the cell's column- Returns:
- the contents of this cell
- Throws:
java.io.IOException
- if there is an error reading the data
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getRow
public java.lang.Object[] getRow(long irow) throws java.io.IOException
Description copied from interface:StarTable
Returns the contents of a given table row. The returned value is equivalent to an array formed of all the objects returned by getCell(irow,icol) for all the columns icol in sequence.- Specified by:
getRow
in interfaceStarTable
- Overrides:
getRow
in classWrapperStarTable
- Parameters:
irow
- the index of the row to retrieve- Returns:
- an array of the objects in each cell in row irow
- Throws:
java.io.IOException
- if there is an error reading the data
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isRandom
public boolean isRandom()
Description copied from interface:StarTable
Indicates whether random access is provided by this table. Only if the result is true may theStarTable.getRow(long)
andStarTable.getCell(long, int)
methods be used.- Specified by:
isRandom
in interfaceStarTable
- Overrides:
isRandom
in classWrapperStarTable
- Returns:
- true if table random access methods are available
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getRowSequence
public RowSequence getRowSequence() throws java.io.IOException
Description copied from interface:StarTable
Returns an object which can iterate over all the rows in the table sequentially.- Specified by:
getRowSequence
in interfaceStarTable
- Overrides:
getRowSequence
in classWrapperStarTable
- Returns:
- an object providing sequential access to the table data
- Throws:
java.io.IOException
- if there is an error providing access
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extendColumnTypes
public static ColumnInfo[] extendColumnTypes(ColumnInfo[] colInfos, StarTable[] tables) throws java.io.IOException
Assembles column metadata objects which are compatible between multiple tables. Nullability, array shape and element size are set to values which can accommodate all of the input tables. If column count or column data types are inconsistent, an IOException is thrown.This utility method is not used by ConcatStarTable instances, but it may be useful when preparing metadata tables for use with the constructor.
- Parameters:
colInfos
- input column metadata objectstables
- list of tables with which columns must be compatible- Returns:
- new array of new column metadata objects, based on input list
- Throws:
java.io.IOException
- if compatibility cannot be achieved
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