uk.ac.starlink.table.jdbc

Class TypeMappers

java.lang.Object

uk.ac.starlink.table.jdbc.TypeMappers

public class TypeMappers
extends java.lang.Object

TypeMapper implementation classes.

Since:

2 Feb 2010

Field Summary

Fields

Modifier and Type	Field and Description
static TypeMapper	DALI TypeMapper implementation like STANDARD, but which uses a 'T' character as the separator between the date and time parts of timestamp serializations.
static TypeMapper	IDENTITY TypeMapper implementation which performs no conversions.
static TypeMapper	STANDARD TypeMapper implementation which performs generally useful conversions.

Method Summary

Modifier and Type	Method and Description
static <T> ValueHandler	createArrayValueHandler(java.sql.ResultSetMetaData meta, int jcol1, java.lang.Class<T> arrayClazz) Constructs a new ValueHandler which converts JDBC Array values to java array objects of a specific type.
static ValueHandler	createIdentityValueHandler(java.sql.ResultSetMetaData meta, int jcol1) Constructs a new ValueHandler which performs no conversions.
static ValueHandler	createStringValueHandler(java.sql.ResultSetMetaData meta, int jcol1) Constructs a new ValueHandler which converts values to Strings.
static ValueHandler	createTimestampValueHandler(java.sql.ResultSetMetaData meta, int jcol1, char dateTimeSeparator) Constructs a new ValueHandler which converts JDBC Timestamp values to Strings, with a configurable date/time separator character.
static java.lang.Class<?>	getArrayClass(java.sql.ResultSetMetaData meta, int jcol1) Tries to guess a suitable output value type for an array-valued column in a ResultSet.

Methods inherited from class java.lang.Object

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

Field Detail

STANDARD

public static final TypeMapper STANDARD

TypeMapper implementation which performs generally useful conversions. In particular, Date subclasses (including java.sql.Date, java.sql.Time and java.sql.Timestamp are turned into Strings, using JDBC timestamp escape format (which is ISO-8601 with a space character separating date and time). The intention is that by using this implementation you will get an output table which can be written using non-specialist output formats such as FITS and VOTable.

DALI

public static final TypeMapper DALI

TypeMapper implementation like STANDARD, but which uses a 'T' character as the separator between the date and time parts of timestamp serializations. Use of the 'T' separator is mandated by the Data Access Layer Interface standard v1.0, section 3.1.2 (http://www.ivoa.net/documents/DALI/), and so is appropriate for output from VO services such as TAP.

IDENTITY

public static final TypeMapper IDENTITY

TypeMapper implementation which performs no conversions. The output types are just as JDBC provides them.

Method Detail

createIdentityValueHandler

public static ValueHandler createIdentityValueHandler(java.sql.ResultSetMetaData meta,
                                                      int jcol1)
                                               throws java.sql.SQLException

Constructs a new ValueHandler which performs no conversions.

Parameters:

meta - JDBC metadata object

jcol1 - JDBC column index (first column is 1)

Throws:

java.sql.SQLException

createStringValueHandler

public static ValueHandler createStringValueHandler(java.sql.ResultSetMetaData meta,
                                                    int jcol1)
                                             throws java.sql.SQLException

Constructs a new ValueHandler which converts values to Strings.

Parameters:

meta - JDBC metadata object

jcol1 - JDBC column index (first column is 1)

Throws:

java.sql.SQLException

createTimestampValueHandler

public static ValueHandler createTimestampValueHandler(java.sql.ResultSetMetaData meta,
                                                       int jcol1,
                                                       char dateTimeSeparator)
                                                throws java.sql.SQLException

Constructs a new ValueHandler which converts JDBC Timestamp values to Strings, with a configurable date/time separator character. The input values are assumed to be of type Timestamp.

Parameters:

meta - JDBC metadata object

jcol1 - JDBC column index (first column is 1)

dateTimeSeparator - separator character between date and time parts of ISO-8601 string; usually either ' ' or 'T'

Throws:

java.sql.SQLException

createArrayValueHandler

public static <T> ValueHandler createArrayValueHandler(java.sql.ResultSetMetaData meta,
                                                       int jcol1,
                                                       java.lang.Class<T> arrayClazz)
                                                throws java.sql.SQLException

Constructs a new ValueHandler which converts JDBC Array values to java array objects of a specific type. This is suitable when ResultSetMetaData.getColumnClassName(int) returns "java.sql.Array".

The required output class arrayClazz must be specified explicitly. If this class not a good match for the payload of the Array values, value conversion won't work very well. The method getArrayClass can be used to guess a good value for this parameter.

Parameters:

meta - JDBC metadata object

jcol1 - JDBC column index (first column is 1)

arrayClazz - required output type

Throws:

java.sql.SQLException

getArrayClass

public static java.lang.Class<?> getArrayClass(java.sql.ResultSetMetaData meta,
                                               int jcol1)

Tries to guess a suitable output value type for an array-valued column in a ResultSet. The returned type will be STIL-friendly, that is a String[] or primitive type array. If the type is not recognised, null is returned.

Parameters:

meta - JDBC metadata object

jcol1 - JDBC column index (first column is 1)

Returns:

best-efforts guess at output array type, or null