oracle.xml.xquery

Class OXQDataSource

java.lang.Object

oracle.xml.xquery.OXQDataSource

All Implemented Interfaces:

XQDataSource

public final class OXQDataSource
extends java.lang.Object
implements XQDataSource

Implements javax.xml.xquery.XQDataSource.

Since:

12.1

See Also:

XQDataSource

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	DEBUG_MODE A property that when set to "true", debugging will be enabled; otherwise, debugging will be disabled.
static java.lang.String	DISABLE_EXPRESSION_TRACKING A property that when set to "true" will prevent a connection from tracking open expressions that are created from it.
static java.lang.String	DOM_PASS_THROUGH A property that when set to "true" relaxes XML data model conversions.
static java.lang.String	IMPORT_SHARING A property that when set to "true", schema and module imports will be shared among queries from the same connection.
static java.lang.String	PESSIMISTIC_TYPE_CHECKING A property that determines if optimistic or pessimistic type checking will be used at compile time.
static java.lang.String	USE_EXTERNAL_STORAGE A property that when set to "true" will cause the query processor use an instance of oracle.xml.scalable.PageManager when materializing XML.

Constructor Summary

Constructors

Constructor and Description
OXQDataSource() Constructs a data source with default properties.
OXQDataSource(java.util.Properties inProperties) Constructs a data source with the specified properties.

Method Summary

Modifier and Type	Method and Description
XQConnection	getConnection() Attempts to create a connection to an XML datasource.
XQConnection	getConnection(java.sql.Connection con) Attempts to create a connection to an XML datasource using an existing JDBC connection.
XQConnection	getConnection(java.lang.String username, java.lang.String passwd) Attempts to establish a connection to an XML datasource using the supplied username and password.
int	getLoginTimeout() Gets the maximum time in seconds that this datasource can wait while attempting to connect to a database.
java.io.PrintWriter	getLogWriter() Retrieves the log writer for this XQDataSource object.
java.lang.String	getProperty(java.lang.String name) Returns the current value of the named property if set, else null.
java.lang.String[]	getSupportedPropertyNames() Returns an array containing the property names supported by this XQDataSource.
void	setLoginTimeout(int seconds) Sets the maximum time in seconds that this datasource will wait while attempting to connect to a database.
void	setLogWriter(java.io.PrintWriter out) Sets the log writer for this XQDataSource object to the given java.io.PrintWriter object.
void	setProperties(java.util.Properties props) Sets the data source properties from the specified Properties instance.
void	setProperty(java.lang.String name, java.lang.String value) Sets the named property to the specified value.

Methods inherited from class java.lang.Object

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

Field Detail

PESSIMISTIC_TYPE_CHECKING

public static final java.lang.String PESSIMISTIC_TYPE_CHECKING

A property that determines if optimistic or pessimistic type checking will be used at compile time. In general, pessimistic type checking will fail whenever the derived type of an expression is not a subtype of the expected type. Optimistic type checking will fail whenever the derived type of an expression does not intersect the expected type. More simply put, pessimistic mode raises an error at compile time if a type might not be correct at runtime. Optimistic mode, on the other hand, only raises an error at compile time when the runtime type check will certainly fail.

When set to "true", pessimistic type checking will be used. For any other value, optimistic type checking will be used. The default value is "false".

See Also:

XQDataSource.setProperty(String, String), Constant Field Values

DEBUG_MODE

public static final java.lang.String DEBUG_MODE

A property that when set to "true", debugging will be enabled; otherwise, debugging will be disabled. The default value of this property is "false"

See Also:

XQDataSource.setProperty(String, String), Constant Field Values

IMPORT_SHARING

public static final java.lang.String IMPORT_SHARING

A property that when set to "true", schema and module imports will be shared among queries from the same connection. The default value of this property is "false"

See Also:

XQDataSource.setProperty(String, String), OXQConnection.getEntityLoader(int), Constant Field Values

DOM_PASS_THROUGH

public static final java.lang.String DOM_PASS_THROUGH

A property that when set to "true" relaxes XML data model conversions. XQuery is designed to process instances of the XQuery and XPath data model (XDM). In several places, the XQJ API facilitates consuming XDM as DOM. For example, XQItemAccessor.getNode() returns the XDM node as a DOM node. The conversion from XDM to DOM is specified in two parts: XDM Infoset Mapping and Appendix C of the DOM specification.

When the input data to the query is DOM and the output of the query is consumed as DOM, it may be desirable to avoid the required data model conversions to improve performance. When this this property is set to "true" DOM may be queried directly without conversion. Note, the processor can not conform strictly to the specifications when in this mode. For example, CDATA nodes, adjacent text nodes, empty text nodes, entity reference nodes, and document type nodes may all appear in the result. The default value of this property is "false".

See Also:

XQDataSource.setProperty(String, String), Constant Field Values

USE_EXTERNAL_STORAGE

public static final java.lang.String USE_EXTERNAL_STORAGE

A property that when set to "true" will cause the query processor use an instance of oracle.xml.scalable.PageManager when materializing XML. There are two scenarios in which the PageManager may be used:

1. If data is bound to the query and the binding mode is BINDING_MODE_IMMEDIATE, then the bound value will be copied into the PageManager. In this case, all pages will be released (deleted) by the time the corresponding XQPreparedExpression or XQExpression is closed.
2. If the query processor needs to materialize intermediate results while processing the query, it will use the PageManager. In this case, all pages will be released (deleted) by the time the corresponding XQResultSequence is closed.

This property must be used in combination with OXQDynamicContext.setPageManager(oracle.xml.scalable.PageManager) Using external storage may drastically reduce the main memory needed to process a query but it may also make query processing take longer.

See Also:

XQDataSource.setProperty(String, String), Constant Field Values

DISABLE_EXPRESSION_TRACKING

public static final java.lang.String DISABLE_EXPRESSION_TRACKING

A property that when set to "true" will prevent a connection from tracking open expressions that are created from it. This is intended for use in cases where multiple threads access the connection and the synchronization needed to track open expressions causes performance problems. When expression tracking is disabled, an attempt to call XQConnection.close() will raise an error so this can only be used in cases where relying on the connection to close expressions is not needed.

See Also:

XQDataSource.setProperty(String, String), Constant Field Values

Constructor Detail

OXQDataSource

public OXQDataSource()

Constructs a data source with default properties.

OXQDataSource

public OXQDataSource(java.util.Properties inProperties)
              throws XQException

Constructs a data source with the specified properties.

Parameters:

inProperties - the data source properties, may not be null

Throws:

XQException - if inProperties is null or if a given property is not supported

Method Detail

getConnection

public XQConnection getConnection()
                           throws XQException

Attempts to create a connection to an XML datasource.

Specified by:

getConnection in interface XQDataSource

Returns:

a connection to the XML datasource

Throws:

XQException - if a datasource access error occurs

getConnection

public XQConnection getConnection(java.sql.Connection con)
                           throws XQException

Attempts to create a connection to an XML datasource using an existing JDBC connection. An XQJ implementation is not required to support this method. If it is not supported, then an exception (XQException) is thrown. The XQJ and JDBC connections will operate under the same transaction context.

Specified by:

getConnection in interface XQDataSource

Parameters:

con - an existing JDBC connection

Returns:

a connection to the XML datasource

Throws:

XQException - if (1) a datasource access error occurs, (2) the implementation does not support this method of getting an XQConnection, or (3) if the con parameter is null

getConnection

public XQConnection getConnection(java.lang.String username,
                                  java.lang.String passwd)
                           throws XQException

Attempts to establish a connection to an XML datasource using the supplied username and password.

Specified by:

getConnection in interface XQDataSource

Parameters:

username - the user on whose behalf the connection is being made

passwd - the user's password

Returns:

a connection to the XML datasource

Throws:

XQException - if a datasource access error occurs

setLoginTimeout

public void setLoginTimeout(int seconds)
                     throws XQException

Sets the maximum time in seconds that this datasource will wait while attempting to connect to a database. A value of zero specifies that the timeout is the default system timeout if there is one; otherwise, it specifies that there is no timeout. When a XQDataSource object is created, the login timeout is initially zero. It is implementation-defined whether the specified login timeout is actually used by the data source implementation. If the connection is created over an existing JDBC connection, then the login timeout value from the underlying JDBC connection may be used.

Specified by:

setLoginTimeout in interface XQDataSource

Parameters:

seconds - the datasource login time limit

Throws:

XQException - if a datasource access error occurs

getLoginTimeout

public int getLoginTimeout()
                    throws XQException

Gets the maximum time in seconds that this datasource can wait while attempting to connect to a database. A value of zero means that the timeout is the default system timeout if there is one; otherwise, it means that there is no timeout. When a XQDataSource object is created, the login timeout is initially zero. It is implementation-defined whether the returned login timeout is actually used by the data source implementation.

Specified by:

getLoginTimeout in interface XQDataSource

Returns:

the datasource login time limit

Throws:

XQException - if a datasource access error occurs

setLogWriter

public void setLogWriter(java.io.PrintWriter out)
                  throws XQException

Sets the log writer for this XQDataSource object to the given java.io.PrintWriter object. The log writer is a character output stream to which all logging and tracing messages for this datasource will be printed. This includes messages printed by the methods of this object, messages printed by methods of other objects manufactured by this object, and so on. When a XQDataSource object is created the log writer is initially null; in other words, the default is for logging to be disabled.

Specified by:

setLogWriter in interface XQDataSource

Parameters:

out - the new log writer; to disable logging, set to null

Throws:

XQException - if a datasource access error occurs

getLogWriter

public java.io.PrintWriter getLogWriter()
                                 throws XQException

Retrieves the log writer for this XQDataSource object. The log writer is a character output stream to which all logging and tracing messages for this datasource will be printed. This includes messages printed by the methods of this object, messages printed by methods of other objects manufactured by this object, and so on. When a XQDataSource object is created, the log writer is initially null; in other words, the default is for logging to be disabled.

Specified by:

getLogWriter in interface XQDataSource

Returns:

the log writer for this datasource or null if logging is disabled

Throws:

XQException - if a datasource access error occurs

getSupportedPropertyNames

public java.lang.String[] getSupportedPropertyNames()

Returns an array containing the property names supported by this XQDataSource. Implementations that support user name and password must recognize the user name and password properties listed below.

user	the user name to use for creating a connection
password	the password to use for creating a connection

Any additional properties are implementation-defined.

Specified by:

getSupportedPropertyNames in interface XQDataSource

Returns:

String[] an array of property names supported by this implementation

setProperty

public void setProperty(java.lang.String name,
                        java.lang.String value)
                 throws XQException

Sets the named property to the specified value. If a property with the same name was already set, then this method will override the old value for that property with the new value.

If the implementation does not support the given property or if it can determine that the value given for this property is invalid, then an exception is thrown. If an exception is thrown, then no previous value is overwritten.

Specified by:

setProperty in interface XQDataSource

Parameters:

name - the name of the property to set

value - the value of the named property

Throws:

XQException - if (1) the given property is not recognized, (2) the value for the given property is determined to be invalid, or (3) the name parameter is null

getProperty

public java.lang.String getProperty(java.lang.String name)
                             throws XQException

Returns the current value of the named property if set, else null. If the implementation does not support the given property then an exception is raised.

Specified by:

getProperty in interface XQDataSource

Parameters:

name - the name of the property whose value is needed

Returns:

String representing the value of the required property if set, else null

Throws:

XQException - if (1) a given property is not supported, or (2) the name parameter is null

setProperties

public void setProperties(java.util.Properties props)
                   throws XQException

Sets the data source properties from the specified Properties instance. Properties set before this call will still apply but those with the same name as any of these properties will be replaced. Properties set after this call also apply and may replace properties set during this call.

If the implementation does not support one or more of the given property names, or if it can determine that the value given for a specific property is invalid, then an exception is thrown. If an exception is thrown, then no previous value is overwritten. is invalid, then an exception is raised.

Specified by:

setProperties in interface XQDataSource

Parameters:

props - the list of properties to set

Throws:

XQException - if (1) a given property is not recognized, (2) the value for a given property is determined to be invalid, or (3) the props parameter is null