IBM DB2 Information Integrator
Java API Reference
for Developing Wrappers

com.ibm.db2.wrapper
Class RequestExp

java.lang.Object
  extended bycom.ibm.db2.wrapper.RequestExp

public class RequestExp
extends java.lang.Object

The RequestExp class represents a node in an expression tree. This node can be a column reference, a constant value, an unbound parameter or an operator. An unbound parameter is similar to a constant. However, its value is unknown until the run-time phase when the federated server passes the value to the wrapper.

Usage:
A RequestExp object is never instantiated by the wrapper. The federated server creates these objects and passes them to the wrapper during query planning.

Since:
IBM DB2 Information Integrator Version 8.2

Field Summary
static int BADKIND
          Constant to indicate that the expression is unknown.
static int COLUMN
          Constant to indicate that the expression is a column.
static int CONSTANT
          Constant to indicate that the expression is a constant.
static int OPERATOR
          Constant to indicate that the expression is an operator.
static int UNBOUND
          Constant to indicate that the expression is an unbound parameter.
 
Method Summary
 java.lang.String getColumnName()
          Column expression node: Retrieve the column name.
 RequestExpType getDataType()
          Retrieve the object that describes the data type of the expression.
 RequestExp getFirstChild()
          Operator expression node: Retrieve the first child of the operator.
 int getHandle()
          Retrieve the expression handle.
 int getKind()
          Retrieve the kind of the expression.
 RequestExp getNextChild()
          Retrieve the sibling of the expression.
 int getNumberOfChildren()
          Operator expression node: Retrieve the number of children for the operator.
 RequestExp getParent()
          Retrieve the parent node of the expression.
 Quantifier getQuantifier()
          Column expression node: Retrieve the quantifier to which this column belongs.
 java.lang.String getSignature()
          Operator expression node: Retrieve the signature of the operator.
 java.lang.String getToken()
          Operator expression node: Retrieve the token of the operator.
 RequestConstant getValue()
          Constant expression node: Retrieve the RequestConstant object that represents the value of the constant.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

BADKIND

public static final int BADKIND
Constant to indicate that the expression is unknown.

Since:
IBM DB2 Information Integrator Version 8.2
See Also:
Constant Field Values

COLUMN

public static final int COLUMN
Constant to indicate that the expression is a column.

Since:
IBM DB2 Information Integrator Version 8.2
See Also:
Constant Field Values

CONSTANT

public static final int CONSTANT
Constant to indicate that the expression is a constant.

Since:
IBM DB2 Information Integrator Version 8.2
See Also:
Constant Field Values

OPERATOR

public static final int OPERATOR
Constant to indicate that the expression is an operator.

Since:
IBM DB2 Information Integrator Version 8.2
See Also:
Constant Field Values

UNBOUND

public static final int UNBOUND
Constant to indicate that the expression is an unbound parameter.

Since:
IBM DB2 Information Integrator Version 8.2
See Also:
Constant Field Values
Method Detail

getColumnName

public java.lang.String getColumnName()
                               throws WrapperException
Column expression node: Retrieve the column name.

Returns:
The column name.
Throws:
WrapperException - if the method is called for non-column expression nodes.
Since:
IBM DB2 Information Integrator Version 8.2

getDataType

public RequestExpType getDataType()
Retrieve the object that describes the data type of the expression.

Returns:
The expression type.
Since:
IBM DB2 Information Integrator Version 8.2
See Also:
RequestExpType

getFirstChild

public RequestExp getFirstChild()
                         throws WrapperException
Operator expression node: Retrieve the first child of the operator.

Returns:
The first child.
Throws:
WrapperException - if the method is called for non-operator expression nodes.
Since:
IBM DB2 Information Integrator Version 8.2

getHandle

public int getHandle()
Retrieve the expression handle.

Returns:
The handle.
Since:
IBM DB2 Information Integrator Version 8.2

getKind

public int getKind()
Retrieve the kind of the expression.

Returns:
The expression kind.
Since:
IBM DB2 Information Integrator Version 8.2

getNextChild

public RequestExp getNextChild()
Retrieve the sibling of the expression.

Returns:
The next sibling or null if the expression does not have a sibling.
Since:
IBM DB2 Information Integrator Version 8.2

getNumberOfChildren

public int getNumberOfChildren()
                        throws WrapperException
Operator expression node: Retrieve the number of children for the operator.

Returns:
The number of children.
Throws:
WrapperException - if the method is called for non-operator expression nodes.
Since:
IBM DB2 Information Integrator Version 8.2

getParent

public RequestExp getParent()
Retrieve the parent node of the expression.

Returns:
The parent expression.
Since:
IBM DB2 Information Integrator Version 8.2

getQuantifier

public Quantifier getQuantifier()
                         throws WrapperException
Column expression node: Retrieve the quantifier to which this column belongs.

Returns:
The quantifier.
Throws:
WrapperException - if the method is called for non-column expression nodes.
Since:
IBM DB2 Information Integrator Version 8.2

getSignature

public java.lang.String getSignature()
                              throws WrapperException
Operator expression node: Retrieve the signature of the operator.

Returns:
The signature of the operator.
Throws:
WrapperException - if the method is called for non-operator expression nodes.
Since:
IBM DB2 Information Integrator Version 8.2

getToken

public java.lang.String getToken()
                          throws WrapperException
Operator expression node: Retrieve the token of the operator.

Returns:
The token of the operator.
Throws:
WrapperException - if the method is called for non-operator expression nodes.
Since:
IBM DB2 Information Integrator Version 8.2

getValue

public RequestConstant getValue()
                         throws WrapperException
Constant expression node: Retrieve the RequestConstant object that represents the value of the constant.

Returns:
The value of the constant as a RequestConstant instance.
Throws:
WrapperException - if the method is called for non-constant expression nodes.
Since:
IBM DB2 Information Integrator Version 8.2
See Also:
RequestConstant

IBM DB2 Information Integrator
Java API Reference
for Developing Wrappers

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