org.eigenbase.sql
Class SqlDynamicParam

java.lang.Object
  org.eigenbase.sql.SqlNode
      org.eigenbase.sql.SqlDynamicParam

All Implemented Interfaces:

Cloneable

public class SqlDynamicParam
extends SqlNode

A SqlDynamicParam represents a dynamic parameter marker in an SQL statement. The textual order in which dynamic parameters appear within an SQL statement is the only property which distinguishes them, so this 0-based index is recorded as soon as the parameter is encountered.

Version:

$Id: //open/dev/farrago/src/org/eigenbase/sql/SqlDynamicParam.java#18 $

Author:

John V. Sichi

Field Summary

private int

index

Fields inherited from class org.eigenbase.sql.SqlNode

emptyArray

Constructor Summary

SqlDynamicParam(int index, SqlParserPos pos)

Method Summary

<R> R	accept(SqlVisitor<R> visitor) Accepts a generic visitor.
SqlNode	clone(SqlParserPos pos) Clones a SqlNode with a different position.
boolean	equalsDeep(SqlNode node, boolean fail) Returns whether this node is structurally equivalent to another node.
int	getIndex()
SqlKind	getKind() Returns the type of node this is, or SqlKind.Other if it's nothing special.
SqlMonotonicity	getMonotonicity(SqlValidatorScope scope) Returns whether expression is always ascending, descending or constant.
void	unparse(SqlWriter writer, int leftPrec, int rightPrec) Writes a SQL representation of this node to a writer.
void	validate(SqlValidator validator, SqlValidatorScope scope) Validates this node.

Methods inherited from class org.eigenbase.sql.SqlNode

clone, cloneArray, equalDeep, findValidOptions, getParserPosition, isA, toSqlString, toSqlString, toString, validateExpr

Methods inherited from class java.lang.Object

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

Field Detail

index

private final int index

Constructor Detail

SqlDynamicParam

public SqlDynamicParam(int index,
                       SqlParserPos pos)

Method Detail

clone

public SqlNode clone(SqlParserPos pos)

Description copied from class: SqlNode

Clones a SqlNode with a different position.

Overrides:

clone in class SqlNode

getKind

public SqlKind getKind()

Description copied from class: SqlNode

Returns the type of node this is, or SqlKind.Other if it's nothing special.

Overrides:

getKind in class SqlNode

Returns:

a SqlKind value, never null

getIndex

public int getIndex()

unparse

public void unparse(SqlWriter writer,
                    int leftPrec,
                    int rightPrec)

Description copied from class: SqlNode

Writes a SQL representation of this node to a writer.

The leftPrec and rightPrec parameters give us enough context to decide whether we need to enclose the expression in parentheses. For example, we need parentheses around "2 + 3" if preceded by "5 *". This is because the precedence of the "*" operator is greater than the precedence of the "+" operator.

The algorithm handles left- and right-associative operators by giving them slightly different left- and right-precedence.

If SqlWriter.isAlwaysUseParentheses() is true, we use parentheses even when they are not required by the precedence rules.

For the details of this algorithm, see SqlCall.unparse(org.eigenbase.sql.SqlWriter, int, int).

Specified by:

unparse in class SqlNode

Parameters:

writer - Target writer

leftPrec - The precedence of the SqlNode immediately preceding this node in a depth-first scan of the parse tree

rightPrec - The precedence of the SqlNode immediately

validate

public void validate(SqlValidator validator,
                     SqlValidatorScope scope)

Description copied from class: SqlNode

Validates this node.

The typical implementation of this method will make a callback to the validator appropriate to the node type and context. The validator has methods such as SqlValidator.validateLiteral(org.eigenbase.sql.SqlLiteral) for these purposes.

Specified by:

validate in class SqlNode

scope - Validator

getMonotonicity

public SqlMonotonicity getMonotonicity(SqlValidatorScope scope)

Description copied from class: SqlNode

Returns whether expression is always ascending, descending or constant. This property is useful because it allows to safely aggregte infinite streams of values.

The default implementation returns SqlMonotonicity.NotMonotonic.

Overrides:

getMonotonicity in class SqlNode

accept

public <R> R accept(SqlVisitor<R> visitor)

Description copied from class: SqlNode

Accepts a generic visitor.

Implementations of this method in subtypes simply call the appropriate visit method on the visitor object.

The type parameter R must be consistent with the type parameter of the visitor.

Specified by:

accept in class SqlNode

equalsDeep

public boolean equalsDeep(SqlNode node,
                          boolean fail)

Description copied from class: SqlNode

Returns whether this node is structurally equivalent to another node. Some examples:

• 1 + 2 is structurally equivalent to 1 + 2
• 1 + 2 + 3 is structurally equivalent to (1 + 2) + 3, but not to 1 + (2 + 3), because the '+' operator is left-associative

Specified by:

equalsDeep in class SqlNode