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public interface XQItemAccessor
This interface represents a common interface for accessing the values of
an XQuery item.
All the get functions raise an exception if the underlying sequence object
is not positioned on an item (e.g. if the sequence is positioned before
the first item or after the last item).
Example -
XQPreparedExpression expr = conn.prepareExpression("for $i .."); XQSequence result = expr.executeQuery(); // create the ItemTypes for string and integer XQItemType strType = conn.createAtomicType(XQItemType.XQBASETYPE_STRING); XQItemType intType = conn.createAtomicType(XQItemType.XQBASETYPE_INTEGER); // posititioned before the first item while (result.next()) { // If string or any of its subtypes, then get the string value out if (result.instanceOf(strType)) String str = result.getAtomicValue(); else if (result.instanceOf(intType)) // if it is exactly an int int intval = result.getInt(); ... // Alternatively, you can get the exact type out. XQItemType type = result.getItemType(); // Now perform the comparison.. if (type.equals(intType)) { ... }; }See also:
xs:unsignedByte
, then calling the getObject()
method
will return a Java object of type java.lang.Short
.
getObject()
or
getNode()
method will return a Java object of type
org.w3.dom.Element
.
Method Summary | |
---|---|
String |
getAtomicValue()
Gets the current item as a Java String . |
boolean |
getBoolean()
Gets the current item as a boolean . |
byte |
getByte()
Gets the current item as a byte . |
double |
getDouble()
Gets the current item as a double . |
float |
getFloat()
Gets the current item as a float . |
int |
getInt()
Gets the current item as an int . |
XMLStreamReader |
getItemAsStream()
Read the current item as an XMLStreamReader object, as described
in Section 12.1 Serializing an XDM instance into a StAX event stream
(XMLStreamReader), XQuery API for Java (XQJ) 1.0. |
String |
getItemAsString(Properties props)
Serializes the current item according to the XSLT 2.0 and XQuery 1.0 serialization. |
XQItemType |
getItemType()
Gets the type of the item. |
long |
getLong()
Gets the current item as a long . |
Node |
getNode()
Gets the item as a DOM node. |
URI |
getNodeUri()
Returns the URI for this item. |
Object |
getObject()
Gets the current item as an Object . |
short |
getShort()
Gets the current item as a short . |
boolean |
instanceOf(XQItemType type)
Checks if the item "matches" an item type, as defined in 2.5.4.2 Matching an Item Type and an Item, XQuery 1.0: An XML Query Language. |
void |
writeItem(OutputStream os,
Properties props)
Serializes the current item to a Writer according to
XSLT 2.0 and XQuery 1.0 serialization. |
void |
writeItem(Writer ow,
Properties props)
Serializes the current item to a Writer according to
XSLT 2.0 and XQuery 1.0 serialization. |
void |
writeItemToResult(Result result)
Writes the current item to a Result . |
void |
writeItemToSAX(ContentHandler saxhdlr)
Writes the current item to a SAX handler, as described in in Section 12.2 Serializing an XDM instance into a SAX event stream, XQuery API for Java (XQJ) 1.0. |
Method Detail |
---|
boolean getBoolean() throws XQException
boolean
.
The current item must be an atomic value of type xs:boolean
or a subtype.
boolean
representing the current item
XQException
- if (1) the conversion of the current item to a
boolean
fails, (2) if there are
errors accessing the current item, (3) if the
underlying sequence or item is in a closed state,
or (4) in the case of forward only sequences, a
get or write method was already invoked on the
current itembyte getByte() throws XQException
byte
.
The current item must be an atomic value of type xs:decimal
or a subtype, and its value must be in the value space of byte
.
byte
representing the current item
XQException
- if (1) the conversion of the current item to a
byte
fails, (2) if there are
errors accessing the current item, (3) if the
underlying sequence or item is in a closed state,
or (4) in the case of forward only sequences, a
get or write method was already invoked on the
current itemdouble getDouble() throws XQException
double
.
The current item must be an atomic value of type xs:double
or a subtype.
double
representing the current item
XQException
- if (1) the conversion of the current item to a
double
fails, (2) if there are
errors accessing the current item, (3) if the
underlying sequence or item is in a closed state,
or (4) in the case of forward only sequences, a
get or write method was already invoked on the
current itemfloat getFloat() throws XQException
float
.
The current item must be an atomic value of type xs:float
or a subtype.
float
representing the current item
XQException
- if (1) the conversion of the current item to a
float
fails, (2) if there are
errors accessing the current item, (3) if the
underlying sequence or item is in a closed state,
or (4) in the case of forward only sequences, a
get or write method was already invoked on the
current itemint getInt() throws XQException
int
.
The current item must be an atomic value of type xs:decimal
or a subtype, and its value must be in the value space of int
.
int
representing the current item
XQException
- if (1) the conversion of the current item to a
int
fails, (2) if there are
errors accessing the current item, (3) if the
underlying sequence or item is in a closed state,
or (4) in the case of forward only sequences, a
get or write method was already invoked on the
current itemXQItemType getItemType() throws XQException
XQException
- if (1) there are errors accessing the type of the item,
or (2) the underlying sequence or item is in a closed stateString getAtomicValue() throws XQException
String
. The current item
must be an atomic value. This function casts the current item to an
xs:string
value according to the casting rules defined in
17.1.2 Casting to xs:string and xs:untypedAtomic, XQuery 1.0 and
XPath 2.0 Functions and Operators,
and then returns the value as a Java String
.
XQException
- if (1) there are errors accessing the item's value,
(2) the item is not an atomic value,
(3) there is an error when casting the
item to a string representation,
(4) the underlying sequence or item is in a
closed state, or (5) in the case of forward only
sequences, a get or write method was already
invoked on the current itemlong getLong() throws XQException
long
.
The current item must be an atomic value of type xs:decimal
or a subtype, and its value must be in the value space of long
.
long
representing the current item
XQException
- if (1) the conversion of the current item to a
long
fails, (2) if there are
errors accessing the current item, (3) if the
underlying sequence or item is in a closed state,
or (4) in the case of forward only sequences, a
get or write method was already invoked on the
current itemNode getNode() throws XQException
XQException
- if (1) if there are errors accessing the current item,
(2) the current item is not a node, (3) if the
underlying sequence or item is in a closed state,
or (4) in the case of forward only sequences, a
get or write method was already invoked on the
current itemURI getNodeUri() throws XQException
fn:document-uri
were evaluated on this document
node. If the item is of a node kind other than document node, then the
returned URI is implementation-defined.
XQException
- if (1) if there are errors accessing the current item,
(2) the current item is not a node, (3) if the
underlying sequence or item is in a closed stateObject getObject() throws XQException
Object
.
The data type of the returned object will be the Java Object
type as specified in 14.4 Mapping an XQuery Atomic Value to a
Java Object Type and 14.5 Mapping an XQuery Node to a Java Object Type,
XQuery API for Java (XQJ) 1.0.
XQException
- if (1) if there are errors accessing the current item,
(2) if the underlying sequence or item is in a closed state,
or (3) in the case of forward only sequences, a
get or write method was already invoked on the
current itemXMLStreamReader getItemAsStream() throws XQException
XMLStreamReader
object, as described
in Section 12.1 Serializing an XDM instance into a StAX event stream
(XMLStreamReader), XQuery API for Java (XQJ) 1.0.
Note that the serialization process might fail, in which case a
XQException
is thrown.
While the stream is being read, the application MUST NOT do any other
concurrent operations on the underlying item or sequence.
The operation on the stream is undefined if the underlying sequence
is repositioned or the state of the underlying item or sequence
is changed by concurrent operations.
XMLStreamReader
XQException
- if (1) there are errors accessing the current item
or the underlying sequence, (2) the underlying sequence
or item is in a closed state, (3) in the case of a forward
only sequence, a get or write method has already been
invoked on the current item, or (4) in case of an error
during serialization of the current item into a StAX event
stream as defined in Section 12.1 Serializing an XDM
instance into a StAX event stream (XMLStreamReader), XQuery
API for Java (XQJ) 1.0String getItemAsString(Properties props) throws XQException
props
- specifies the serialization parameters,
null
is considered equivalent to an empty
Properties
object
XQException
- if (1) there are errors accessing the current
item or the underlying sequence, (2) the underlying
sequence or item is in a closed state,
(3) in the case of a forward only sequence,
a get or write method has already been
invoked on the current item, or (4)
if there are errors during serializationshort getShort() throws XQException
short
.
The current item must be an atomic value of type xs:decimal
or a subtype, and its value must be in the value space of short
.
short
representing the current item
XQException
- if (1) the conversion of the current item to a
short
fails, (2) if there are
errors accessing the current item, (3) if the
underlying sequence or item is in a closed state,
or (4) in the case of forward only sequences, a
get or write method was already invoked on the
current itemboolean instanceOf(XQItemType type) throws XQException
... XQItemType strType = conn.createAtomicType(XQItemType.XQBASETYPE_STRING); XQItemType nodeType = conn.createNodeType(); XQSequence result = preparedExpr.executeQuery(); while (result.next()) { // Generic check for node.. if (result.instanceOf(nodeType)) org.w3.dom.Node node = result.getNode(); else if (result.instanceOf(strType)) String str = result.getAtomicValue(); }
XQItemAccessor
or the input
XQItemType
is not a built-in type, then this method is
allowed to raise exception if it can NOT determine the instanceOf
relationship due to the lack of the access of
the XML schema that defines the user defined schema types if the
XQMetaData.isUserDefinedXMLSchemaTypeSupported()
method
returns false
.
XQItemAccessor
is an instance of the input
XQItemType
. Note even if
isUserDefinedXMLSchemaTypeSupported()
returns false
,
an XQJ implementation may still be able to determine the instanceOf
relationship for certain cases involving user defined schema type.
For example, if the type of an XQItemAccessor
is of
mySchema:hatSize
sequence type and the input parameter
XQItemType
is of item()
sequence type,
the return value for instanceOf relationship should always be true
even though the XQJ implementation does not know the precise type
information of mySchema:hatSize
type defined in XML
schema 'mySchema'
.
type
- item type to match
true
if this item matches
the input item type as defined in
2.5.4.2 Matching an Item Type and an Item,
XQuery 1.0: An XML Query Language,
and false
if it does not
XQException
- if (1) there are errors accessing the item's
type, (2) if the underlying sequence or item
is in a closed state, (3) if the implementation
is unable to determine the schema definition of a
user defined schema type, or (4) the type
parameter is null
void writeItem(OutputStream os, Properties props) throws XQException
Writer
according to
XSLT 2.0 and XQuery 1.0 serialization.
Serialization parameters, which influence how serialization is
performed, can be specified. Refer to the
XSLT 2.0 and XQuery 1.0 serialization
and Section 12 Serialization, XQuery
API for Java (XQJ) 1.0 for more information.
os
- the output stream into which the current item is
to be serializedprops
- specifies the serialization parameters,
null
is considered equivalent to an empty
Properties
object
XQException
- if (1) there are errors accessing the current
item or the underlying sequence, (2) the underlying
sequence or item is in a closed state,
(3) in the case of a forward only sequence, a get or
write method has already been invoked on the current item,
(4) if there are errors during serialization, or
(5) the os
parameter is null
void writeItem(Writer ow, Properties props) throws XQException
Writer
according to
XSLT 2.0 and XQuery 1.0 serialization.
Serialization parameters, which influence how serialization is
performed, can be specified. Refer to the
XSLT 2.0 and XQuery 1.0 serialization
and Section 12 Serialization, XQuery
API for Java (XQJ) 1.0 for more information.
Writer
, make sure the writer's encoding
matches the encoding parameter if specified as a property or the default
encoding.
ow
- the writer object into which the current item is to be
serializedprops
- specifies the serialization parameters,
null
is considered equivalent to an empty
Properties
object
XQException
- if (1) there are errors accessing the current
item or the underlying sequence, (2) the underlying
sequence or item is in a closed state,
(3) in the case of a forward only sequence, a get or
write method has already been invoked on the current item,
(4) if there are errors during serialization, or
(5) the ow
parameter is null
void writeItemToSAX(ContentHandler saxhdlr) throws XQException
XQException
is thrown.
The specified org.xml.sax.ContentHandler
can optionally implement the
org.xml.sax.LexicalHandler
interface. An implementation must check if the
specified ContentHandler
implements LexicalHandler
.
If the handler is a LexicalHandler
comment nodes are reported, otherwise
they will be silently ignored.
saxhdlr
- the SAX content handler, optionally a lexical handler
XQException
- if (1) there are errors accessing the current
item or the underlying sequence, (2) the underlying
sequence or item is in a closed state, (3) in the case
of a forward only sequence, a get or write method has
already been invoked on the current item, (4) in case
of an error while serializing the XDM instance
into a SAX event stream, or (5) the saxhdlr
parameter is null
void writeItemToResult(Result result) throws XQException
Result
. First the item is
normalized as described in
XSLT 2.0 and XQuery 1.0 serialization. Subsequently it is
serialized to the Result
object.XQException
is thrown.
An XQJ implementation must at least support the following implementations:
javax.xml.transform.dom.DOMResult
javax.xml.transform.sax.SAXResult
javax.xml.transform.stream.StreamResult
result
- the result object into which the item is to be serialized
XQException
- if (1) there are errors accessing the current
item or the underlying sequence, (2) the underlying
sequence or item is in a closed state, (3) in the case
of a forward only sequence, a get or write method has
already been invoked on the current item, (4) in case
of an error while serializing the current item into the
Result
object, or (5) the result
parameter is null
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