de.ipcon.db.oql

Class OQLQuery

java.lang.Object

de.ipcon.db.oql.OQLQuery

public class OQLQuery
extends java.lang.Object

Main entry point for compiling OQL strings into executable SQL queries.

Note: This engine utilizes a two-tier soft-reference cache to maximize throughput:

• If an OQL query has no bind parameters, the fully rendered SQLQuery is cached.
• If an OQL query uses parameters (e.g. $1), the parsed AST (OQLQuery) is cached, allowing subsequent calls to rapidly generate new SQLQuery objects with different arguments without re-parsing the grammar.

Usage:

 SQLQuery sqlQuery = OQLQuery.compile(schema, "select a from BO a", args);
 

Constructor Summary

Constructors

Constructor and Description
OQLQuery(SchemaI schema, java.lang.String queryString) Parses a raw OQL string into an internal Abstract Syntax Tree (AST).

Method Summary

Modifier and Type	Method and Description
static SQLQuery	compile(SchemaI schema, java.lang.String queryString, java.lang.Object[] oqlArgs) Compiles an OQL string into a fully executable JDBC SQL query, utilizing the memory-sensitive cache.
int	getExpectedRows(java.lang.Object[] oqlArgs)
static int	getExpectedRows(QueryExpressionNode parsedTree, java.lang.Object[] oqlArgs) Attempts to heuristically determine the expected row count from the AST nodes.
QueryExpressionNode	getParsedTree()
SchemaI	getSchema()

Methods inherited from class java.lang.Object

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

Constructor Detail

OQLQuery

public OQLQuery(SchemaI schema,
                java.lang.String queryString)
         throws OQLException

Parses a raw OQL string into an internal Abstract Syntax Tree (AST).

Parameters:

schema - the schema definition used for type resolution

queryString - the raw OQL string to parse

Throws:

OQLException - if the syntax is invalid or type resolution fails

Method Detail

compile

public static SQLQuery compile(SchemaI schema,
                               java.lang.String queryString,
                               java.lang.Object[] oqlArgs)
                        throws OQLException

Compiles an OQL string into a fully executable JDBC SQL query, utilizing the memory-sensitive cache.

Parameters:

schema - the schema definition

queryString - the raw OQL string

oqlArgs - the positional arguments mapped to the OQL variables

Returns:

an immutable SQL query mapped to the provided arguments

Throws:

OQLException

getSchema

public SchemaI getSchema()

getParsedTree

public QueryExpressionNode getParsedTree()

getExpectedRows

public int getExpectedRows(java.lang.Object[] oqlArgs)

getExpectedRows

public static int getExpectedRows(QueryExpressionNode parsedTree,
                                  java.lang.Object[] oqlArgs)

Attempts to heuristically determine the expected row count from the AST nodes.

Returns:

the expected row count, or SQLQuery.NO_LIMIT if statically indeterminate