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org.hsqldb
Class Function  

java.lang.Object
  org.hsqldb.Function

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class Function

extends java.lang.Object

Provides services to evaluate Java methods in the context of SQL function and stored procedure calls.

Version:

1.7.0

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Field Summary
private  boolean[]	bArgNullable
private  boolean	bConnection
private  Session	cSession
private  Expression[]	eArg
private  int	iArgCount
private  int[]	iArgType
private  int	iReturnType
private  boolean	isIdentityFunction
private static java.util.Hashtable	methodCache
private  java.lang.reflect.Method	mMethod
private  java.lang.Object[]	oArg
private  java.lang.String	sFunction

 

Constructor Summary
(package private)	Function(java.lang.String function, Session session)           Constructs a new Function object with the given function call name and using the specified Session context.

 

Method Summary
(package private)  void	checkResolved()           Checks each of this object's arguments for resolution, throwing a SQLException if any arguments have not yet been resolved.
(package private)  int	getArgCount()           Retrieves the number of parameters that must be supplied to evaluate this Function object from SQL.
(package private)  int	getArgType(int i)           Retrieves the java.sql.Types type of the argument at the specified offset in this Function object's paramter list
(package private)  int	getReturnType()           Retrieves the java.sql.Types type of this Function object's return type
(package private)  java.lang.Object	getValue()           Retrieves the value this Function evaluates to, given the current state of this object's resolved 55 TableFilter, if any, and any mapping of expressions to this Function's parameter list that has been performed via {link #setArgument(int,Expression) setArgument}.
(package private)  void	resolve(TableFilter f)           Resolves the arguments supplied to this Function object against the specified TableFilter.
(package private)  void	setArgument(int i, Expression e)           Binds the specified expression to the specified argument in this Function object's paramter list.

 

Methods inherited from class java.lang.Object

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

 

Field Detail

cSession

private Session cSession

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sFunction

private java.lang.String sFunction

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mMethod

private java.lang.reflect.Method mMethod

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iReturnType

private int iReturnType

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iArgCount

private int iArgCount

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iArgType

private int[] iArgType

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bArgNullable

private boolean[] bArgNullable

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oArg

private java.lang.Object[] oArg

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eArg

private Expression[] eArg

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bConnection

private boolean bConnection

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isIdentityFunction

private boolean isIdentityFunction

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methodCache

private static java.util.Hashtable methodCache

Constructor Detail

Function

Function(java.lang.String function,
         Session session)
   throws java.sql.SQLException

Constructs a new Function object with the given function call name and using the specified Session context.

The call name is the fully qualified name of a static Java method, as opposed to the method's canonical signature. That is, the name is of the form "package.class.method." This implies that Java methods with the same fully qualified name but different signatures cannot be used properly as HSQLDB SQL functions or stored procedures. For instance, it is impossible to call both System.getProperty(String) and System.getProperty(String,String) under this arrangement, because the HSQLDB Function object is unable to differentiate between the two; it simply chooses the first method matching the FQN in the array of methods obtained from calling getMethods() on an instance of the Class indicated in the FQN, hiding all other methods with the same FQN.

The function FQN must match at least one static Java method FQN in the specified class or construction cannot procede and a SQLException is thrown.

The Session paramter is the connected context in which this Function object will evaluate. If it is determined that the connected user does not have the right to evaluate this Function, construction cannot proceed and a SQLException is thrown.

Method Detail

getValue

java.lang.Object getValue()
                    throws java.sql.SQLException

Retrieves the value this Function evaluates to, given the current state of this object's resolved 55 TableFilter, if any, and any mapping of expressions to this Function's parameter list that has been performed via {link #setArgument(int,Expression) setArgument}.

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getArgCount

int getArgCount()

Retrieves the number of parameters that must be supplied to evaluate this Function object from SQL.

This value may be different than the number of parameters of the underlying Java method. This is because HSQLDB automatically detects if the first parameter is of type java.sql.Connection, and supplies a live Connection object constructed from the evaluating session context if so.

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resolve

void resolve(TableFilter f)
       throws java.sql.SQLException

Resolves the arguments supplied to this Function object against the specified TableFilter.

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checkResolved

void checkResolved()
             throws java.sql.SQLException

Checks each of this object's arguments for resolution, throwing a SQLException if any arguments have not yet been resolved.

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getArgType

int getArgType(int i)

Retrieves the java.sql.Types type of the argument at the specified offset in this Function object's paramter list

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getReturnType

int getReturnType()

Retrieves the java.sql.Types type of this Function object's return type

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setArgument

void setArgument(int i,
                 Expression e)

Binds the specified expression to the specified argument in this Function object's paramter list.

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Overview  Package   Class  Use  Deprecated  Index
Home >> All >> org >> [ hsqldb overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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