Support (jTDS API)

java.lang.Object
- net.sourceforge.jtds.jdbc.Support

```
public class Support
extends java.lang.Object
```
This class contains static utility methods designed to support the main driver classes.
Implementation notes:
1. The methods in this class incorporate some code from previous versions of jTDS to handle dates, BLobs etc.
2. This class contains routines to generate runtime messages from the resource file.
3. The key data conversion logic used in Statements and result sets is implemented here.
4. There is nothing here which is TDS specific.
Version:

$Id: Support.java,v 1.56.2.6 2010-05-17 09:36:57 ickzon Exp $

Author:

Mike Hutchinson, jTDS project

Field Summary

Fields
Modifier and Type	Field and Description
`private static java.math.BigDecimal`	`BIG_DECIMAL_ONE`
`private static java.math.BigDecimal`	`BIG_DECIMAL_ZERO`
`private static java.sql.Date`	`DATE_ZERO`
`private static java.lang.Double`	`DOUBLE_ONE`
`private static java.lang.Double`	`DOUBLE_ZERO`
`private static java.lang.Float`	`FLOAT_ONE`
`private static java.lang.Float`	`FLOAT_ZERO`
`private static char[]`	`hex` Hex constants to use in conversion routines.
`private static java.lang.Integer`	`INTEGER_ONE`
`private static java.lang.Integer`	`INTEGER_ZERO`
`private static java.lang.Long`	`LONG_ONE`
`private static java.lang.Long`	`LONG_ZERO`
`private static java.math.BigInteger`	`MAX_VALUE_28`
`private static java.math.BigInteger`	`MAX_VALUE_38`
`private static java.math.BigDecimal`	`MAX_VALUE_LONG_BD`
`private static java.math.BigInteger`	`MAX_VALUE_LONG_BI`
`private static java.math.BigDecimal`	`MIN_VALUE_LONG_BD`
`private static java.math.BigInteger`	`MIN_VALUE_LONG_BI`
`private static java.sql.Time`	`TIME_ZERO`
`private static java.util.HashMap`	`typeMap` Convert java clases to java.sql.Type constant.

Constructor Summary

Constructors
Modifier Constructor and Description

private Support()

Constructors
Modifier	Constructor and Description
`private`	`Support()`

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`(package private) static int`	`calculateNamedPipeBufferSize(int tdsVersion, int packetSize)` Calculate the buffer size to use when buffering the `InputStream` for named pipes.
`(package private) static java.lang.Object`	`castNumeric(java.lang.Object orig, int sourceType, int targetType)`
`(package private) static java.lang.Object`	`convert(java.lang.Object callerReference, java.lang.Object x, int jdbcType, java.lang.String charSet)` Convert an existing data object to the specified JDBC type.
`static java.lang.Object`	`convertLOB(java.lang.Object value)` Converts a LOB to the equivalent Java type, i.e.
`static int`	`convertLOBType(int type)` Converts a LOB type constant to the equivalent Java type constant, i.e.
`(package private) static void`	`embedData(java.lang.StringBuilder buf, java.lang.Object value, boolean isUnicode, JtdsConnection connection)` Embed the data object as a string literal in the buffer supplied.
`(package private) static byte[]`	`encodeString(java.lang.String cs, java.lang.String value)` Encode a string into a byte array using the specified character set.
`(package private) static java.lang.String`	`getClassName(int jdbcType)` Retrieve the fully qualified java class name for the supplied JDBC Types constant.
`private static JtdsConnection`	`getConnection(java.lang.Object callerReference)` Returns the connection for a given `ResultSet`, `Statement` or `Connection` object.
`(package private) static int`	`getJdbcType(java.lang.Class typeClass)` Get the JDBC type constant which matches the supplied `Class`.
`(package private) static int`	`getJdbcType(java.lang.Object value)` Get the JDBC type constant which matches the supplied Object type.
`(package private) static java.lang.String`	`getJdbcTypeName(int jdbcType)` Get a String describing the supplied JDBC type constant.
`(package private) static java.lang.String`	`getParameterDefinitions(ParamInfo[] parameters)` Constructs a parameter definition string for use with sp_executesql, sp_prepare, sp_prepexec, sp_cursoropen, sp_cursorprepare and sp_cursorprepexec.
`(package private) static java.lang.String`	`getStatementKey(java.lang.String sql, ParamInfo[] params, int serverType, java.lang.String catalog, boolean autoCommit, boolean cursor)` Generates a unique statement key for a given SQL statement.
`static boolean`	`isWindowsOS()` Checks the `os.name` system property to see if it starts with "windows".
`static java.lang.Throwable`	`linkException(java.lang.Exception exception, java.lang.Throwable cause)` Link the original cause to an `Exception`.
`static java.sql.SQLException`	`linkException(java.sql.SQLException sqle, java.lang.Throwable cause)` Link the original cause to an `SQLException`.
`static java.sql.SQLWarning`	`linkException(java.sql.SQLWarning sqle, java.lang.Throwable cause)` Link the original cause to an `SQLWarning`.
`(package private) static java.math.BigDecimal`	`normalizeBigDecimal(java.math.BigDecimal value, int maxPrecision)` Normalize a BigDecimal value so that it fits within the available precision.
`(package private) static java.lang.String`	`substituteParameters(java.lang.String sql, ParamInfo[] list, JtdsConnection connection)` Substitute actual data for the parameter markers to simulate parameter substitution in a PreparedStatement.
`(package private) static java.lang.String`	`substituteParamMarkers(java.lang.String sql, ParamInfo[] list)` Update the SQL string and replace the ? markers with parameter names eg @P0, @P1 etc.
`static long`	`timeFromZone(java.util.Date value, java.util.Calendar target)` Convert a timestamp from a different Timezone.
`static long`	`timeToZone(java.util.Date value, java.util.Calendar target)` Convert a timestamp to a different Timezone.
`static java.lang.String`	`toHex(byte[] bytes)` Convert a byte[] object to a hex string.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - INTEGER_ZERO
```
private static final java.lang.Integer INTEGER_ZERO
```
  - INTEGER_ONE
```
private static final java.lang.Integer INTEGER_ONE
```
  - LONG_ZERO
```
private static final java.lang.Long LONG_ZERO
```
  - LONG_ONE
```
private static final java.lang.Long LONG_ONE
```
  - FLOAT_ZERO
```
private static final java.lang.Float FLOAT_ZERO
```
  - FLOAT_ONE
```
private static final java.lang.Float FLOAT_ONE
```
  - DOUBLE_ZERO
```
private static final java.lang.Double DOUBLE_ZERO
```
  - DOUBLE_ONE
```
private static final java.lang.Double DOUBLE_ONE
```
  - BIG_DECIMAL_ZERO
```
private static final java.math.BigDecimal BIG_DECIMAL_ZERO
```
  - BIG_DECIMAL_ONE
```
private static final java.math.BigDecimal BIG_DECIMAL_ONE
```
  - DATE_ZERO
```
private static final java.sql.Date DATE_ZERO
```
  - TIME_ZERO
```
private static final java.sql.Time TIME_ZERO
```
  - MIN_VALUE_LONG_BI
```
private static final java.math.BigInteger MIN_VALUE_LONG_BI
```
  - MAX_VALUE_LONG_BI
```
private static final java.math.BigInteger MAX_VALUE_LONG_BI
```
  - MIN_VALUE_LONG_BD
```
private static final java.math.BigDecimal MIN_VALUE_LONG_BD
```
  - MAX_VALUE_LONG_BD
```
private static final java.math.BigDecimal MAX_VALUE_LONG_BD
```
  - MAX_VALUE_28
```
private static final java.math.BigInteger MAX_VALUE_28
```
  - MAX_VALUE_38
```
private static final java.math.BigInteger MAX_VALUE_38
```
  - typeMap
```
private static final java.util.HashMap typeMap
```
    Convert java clases to java.sql.Type constant.
  - hex
```
private static final char[] hex
```
    Hex constants to use in conversion routines.
- Constructor Detail
  - Support
```
private Support()
```
- Method Detail
  - toHex
```
public static java.lang.String toHex(byte[] bytes)
```
    Convert a byte[] object to a hex string.
    
    Parameters:
    
    bytes - The byte array to convert.
    
    Returns:
    
    The hex equivalent as a String.
  - normalizeBigDecimal
```
static java.math.BigDecimal normalizeBigDecimal(java.math.BigDecimal value,
                                                int maxPrecision)
                                         throws java.sql.SQLException
```
    Normalize a BigDecimal value so that it fits within the available precision.
    
    Parameters:
    
    value - The decimal value to normalize.
    
    maxPrecision - The decimal precision supported by the server (assumed to be a value of either 28 or 38).
    
    Returns:
    
    The possibly normalized decimal value as a BigDecimal.
    
    Throws:
    
    java.sql.SQLException - If the number is too big.
  - castNumeric
```
static java.lang.Object castNumeric(java.lang.Object orig,
                                    int sourceType,
                                    int targetType)
```
  - convert
```
static java.lang.Object convert(java.lang.Object callerReference,
                                java.lang.Object x,
                                int jdbcType,
                                java.lang.String charSet)
                         throws java.sql.SQLException
```
    Convert an existing data object to the specified JDBC type.
    
    Parameters:
    
    callerReference - an object reference to the caller of this method; must be a Connection, Statement or ResultSet
    
    x - the data object to convert
    
    jdbcType - the required type constant from java.sql.Types
    
    Returns:
    
    the converted data object
    
    Throws:
    
    java.sql.SQLException - if the conversion is not supported or fails
  - getJdbcType
```
static int getJdbcType(java.lang.Object value)
```
    Get the JDBC type constant which matches the supplied Object type.
    
    Parameters:
    
    value - The object to analyse.
    
    Returns:
    
    The JDBC type constant as an int.
  - getJdbcType
```
static int getJdbcType(java.lang.Class typeClass)
```
    Get the JDBC type constant which matches the supplied Class.
    
    Parameters:
    
    typeClass - the Class to analyse
    
    Returns:
    
    the JDBC type constant as an int
  - getJdbcTypeName
```
static java.lang.String getJdbcTypeName(int jdbcType)
```
    Get a String describing the supplied JDBC type constant.
    
    Parameters:
    
    jdbcType - The constant to be decoded.
    
    Returns:
    
    The text decode of the type constant as a String.
  - getClassName
```
static java.lang.String getClassName(int jdbcType)
```
    Retrieve the fully qualified java class name for the supplied JDBC Types constant.
    
    Parameters:
    
    jdbcType - The JDBC Types constant.
    
    Returns:
    
    The fully qualified java class name as a String.
  - embedData
```
static void embedData(java.lang.StringBuilder buf,
                      java.lang.Object value,
                      boolean isUnicode,
                      JtdsConnection connection)
               throws java.sql.SQLException
```
    Embed the data object as a string literal in the buffer supplied.
    
    Parameters:
    
    buf - The buffer in which the data will be embedded.
    
    value - The data object.
    
    isUnicode - Set to true if Unicode strings should be used, else false.
    
    connection - The JtdsConnection object.
    
    Throws:
    
    java.sql.SQLException
  - getStatementKey
```
static java.lang.String getStatementKey(java.lang.String sql,
                                        ParamInfo[] params,
                                        int serverType,
                                        java.lang.String catalog,
                                        boolean autoCommit,
                                        boolean cursor)
```
    Generates a unique statement key for a given SQL statement.
    
    Parameters:
    
    sql - the sql statement to generate the key for
    
    params - the statement parameters
    
    serverType - the type of server to generate the key for
    
    catalog - the catalog is required for uniqueness on Microsoft SQL Server
    
    autoCommit - true if in auto commit mode
    
    cursor - true if this is a prepared cursor
    
    Returns:
    
    the unique statement key
  - getParameterDefinitions
```
static java.lang.String getParameterDefinitions(ParamInfo[] parameters)
```
    Constructs a parameter definition string for use with sp_executesql, sp_prepare, sp_prepexec, sp_cursoropen, sp_cursorprepare and sp_cursorprepexec.
    
    Parameters:
    
    parameters - Parameters to construct the definition for
    
    Returns:
    
    a parameter definition string
  - substituteParamMarkers
```
static java.lang.String substituteParamMarkers(java.lang.String sql,
                                               ParamInfo[] list)
```
    Update the SQL string and replace the ? markers with parameter names eg @P0, @P1 etc.
    
    Parameters:
    
    sql - the SQL containing markers to substitute
    
    list - the parameter list
    
    Returns:
    
    the modified SQL as a String
  - substituteParameters
```
static java.lang.String substituteParameters(java.lang.String sql,
                                             ParamInfo[] list,
                                             JtdsConnection connection)
                                      throws java.sql.SQLException
```
    Substitute actual data for the parameter markers to simulate parameter substitution in a PreparedStatement.
    
    Parameters:
    
    sql - The SQL containing parameter markers to substitute.
    
    list - The parameter descriptors.
    
    connection - The current connection.
    
    Returns:
    
    The modified SQL statement.
    
    Throws:
    
    java.sql.SQLException
  - encodeString
```
static byte[] encodeString(java.lang.String cs,
                           java.lang.String value)
```
    Encode a string into a byte array using the specified character set.
    
    Parameters:
    
    cs - The Charset name.
    
    value - The value to encode.
    
    Returns:
    
    The value of the String as a byte[].
  - linkException
```
public static java.sql.SQLWarning linkException(java.sql.SQLWarning sqle,
                                                java.lang.Throwable cause)
```
    Link the original cause to an SQLWarning.
    This convenience method calls linkException(Exception, Throwable) and casts the result for cleaner code elsewhere.
    
    Parameters:
    
    sqle - The SQLWarning to enhance.
    
    cause - The Throwable to link.
    
    Returns:
    
    The original SQLWarning object.
  - linkException
```
public static java.sql.SQLException linkException(java.sql.SQLException sqle,
                                                  java.lang.Throwable cause)
```
    Link the original cause to an SQLException.
    This convenience method calls linkException(Exception, Throwable) and casts the result for cleaner code elsewhere.
    
    Parameters:
    
    sqle - The SQLException to enhance.
    
    cause - The Throwable to link.
    
    Returns:
    
    The original SQLException object.
  - linkException
```
public static java.lang.Throwable linkException(java.lang.Exception exception,
                                                java.lang.Throwable cause)
```
    Link the original cause to an Exception.
    If running under JVM 1.4+ the Throwable.initCause(Throwable) method will be invoked to chain the exception, else the exception is logged via the Logger class. Modeled after the code written by Brian Heineman.
    
    Parameters:
    
    exception - The Exception to enhance.
    
    cause - The Throwable to link.
    
    Returns:
    
    The original Exception object.
  - timeToZone
```
public static long timeToZone(java.util.Date value,
                              java.util.Calendar target)
```
    Convert a timestamp to a different Timezone.
    
    Parameters:
    
    value - the timestamp value
    
    target - the Calendar containing the TimeZone
    
    Returns:
    
    the new timestamp value as a long
  - timeFromZone
```
public static long timeFromZone(java.util.Date value,
                                java.util.Calendar target)
```
    Convert a timestamp from a different Timezone.
    
    Parameters:
    
    value - the timestamp value.
    
    target - the Calendar containing the TimeZone.
    
    Returns:
    
    The new timestamp value as a long.
  - convertLOB
```
public static java.lang.Object convertLOB(java.lang.Object value)
                                   throws java.sql.SQLException
```
    Converts a LOB to the equivalent Java type, i.e. Clob to String and Blob to byte[]. If the value passed is not a LOB object, it is left unchanged and no exception is thrown; the idea is to transparently convert only LOBs.
    
    Parameters:
    
    value - an object that may be a LOB
    
    Returns:
    
    if the value was a LOB, the equivalent Java object, otherwise the original value
    
    Throws:
    
    java.sql.SQLException - if an error occurs while reading the LOB contents
  - convertLOBType
```
public static int convertLOBType(int type)
```
    Converts a LOB type constant to the equivalent Java type constant, i.e. Types.CLOB to Types.LONGVARCHAR and Types.BLOB to Types.LONGVARBINARY. If the type passed is not that of a LOB, it is left unchanged and no exception is thrown; the idea is to transparently convert only LOB types.
    
    Parameters:
    
    type - a Types constant defining a JDBC type, possibly a LOB
    
    Returns:
    
    if the type was that of a LOB, the equivalent Java object type, otherwise the original type
  - isWindowsOS
```
public static boolean isWindowsOS()
```
    Checks the os.name system property to see if it starts with "windows".
    
    Returns:
    
    true if os.name starts with "windows", else false.
  - getConnection
```
private static JtdsConnection getConnection(java.lang.Object callerReference)
```
    Returns the connection for a given ResultSet, Statement or Connection object.
    
    Parameters:
    
    callerReference - an object reference to the caller of this method; must be a Connection, Statement or ResultSet
    
    Returns:
    
    a connection
  - calculateNamedPipeBufferSize
```
static int calculateNamedPipeBufferSize(int tdsVersion,
                                        int packetSize)
```
    Calculate the buffer size to use when buffering the InputStream for named pipes.
    The buffer size is tied directly to the packet size because each request to the SmbNamedPipe will send a request for a particular size of packet. In other words, if you only request 1 byte, the SmbNamedPipe will send a request out and only ask for 1 byte back. Buffering the expected packet size ensures that all of the data will be returned in the buffer without wasting any space.
    
    Parameters:
    
    tdsVersion - the TDS version for the connection
    
    packetSize - requested packet size for the connection
    
    Returns:
    
    minimum default packet size if packetSize == 0, else packetSize

Class Support

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

INTEGER_ZERO

INTEGER_ONE

LONG_ZERO

LONG_ONE

FLOAT_ZERO

FLOAT_ONE

DOUBLE_ZERO

DOUBLE_ONE

BIG_DECIMAL_ZERO

BIG_DECIMAL_ONE

DATE_ZERO

TIME_ZERO

MIN_VALUE_LONG_BI

MAX_VALUE_LONG_BI

MIN_VALUE_LONG_BD

MAX_VALUE_LONG_BD

MAX_VALUE_28

MAX_VALUE_38

typeMap

hex

Constructor Detail

Support

Method Detail

toHex

normalizeBigDecimal

castNumeric

convert

getJdbcType

getJdbcType

getJdbcTypeName

getClassName

embedData

getStatementKey

getParameterDefinitions

substituteParamMarkers

substituteParameters

encodeString

linkException

linkException

linkException

timeToZone

timeFromZone

convertLOB

convertLOBType

isWindowsOS

getConnection

calculateNamedPipeBufferSize