net.sf.saxon.value
Class ObjectValue

java.lang.Object
  extended by net.sf.saxon.value.Value
      extended by net.sf.saxon.value.AtomicValue
          extended by net.sf.saxon.value.ObjectValue
All Implemented Interfaces:
Serializable, PullEvent, SequenceIterable, GroundedValue, Item, ValueRepresentation, ConversionResult
Direct Known Subclasses:
FirstClassFunction

public class ObjectValue
extends AtomicValue

An XPath value that encapsulates a Java object. Such a value can only be obtained by calling an extension function that returns it.

See Also:
Serialized Form

Field Summary
 
Fields inherited from class net.sf.saxon.value.Value
EMPTY_CLASS_ARRAY, INDETERMINATE_ORDERING
 
Fields inherited from interface net.sf.saxon.om.ValueRepresentation
EMPTY_VALUE_ARRAY
 
Fields inherited from interface net.sf.saxon.om.ValueRepresentation
EMPTY_VALUE_ARRAY
 
Constructor Summary
ObjectValue()
          Default constructor for use in subclasses
ObjectValue(Object object)
          Constructor
ObjectValue(Object object, ExternalObjectType type)
          Constructor
 
Method Summary
 ConversionResult convertPrimitive(BuiltInAtomicType requiredType, boolean validate, XPathContext context)
          Convert to target data type
 Object convertToJava(Class target, XPathContext context)
          Convert to Java object (for passing to external functions)
 AtomicValue copyAsSubType(AtomicType typeLabel)
          Create a copy of this atomic value, with a different type label
 String displayTypeName()
          Display the type name for use in error messages
 boolean effectiveBooleanValue()
          Get the effective boolean value of the value
 boolean equals(Object other)
          Determine if two ObjectValues are equal
 ItemType getItemType(TypeHierarchy th)
          Determine the data type of the items in the expression, if possible
 Object getObject()
          Get the encapsulated object
 BuiltInAtomicType getPrimitiveType()
          Determine the primitive type of the value.
 Comparable getSchemaComparable()
          Get a Comparable value that implements the XML Schema ordering comparison semantics for this value.
 String getStringValue()
          Get the value as a String
 Object getXPathComparable(boolean ordered, StringCollator collator, XPathContext context)
          Get an object value that implements the XPath equality and ordering comparison semantics for this value.
 int hashCode()
           
 void setValue(Object value)
          Set the value in this object value
 
Methods inherited from class net.sf.saxon.value.AtomicValue
asAtomic, checkPermittedContents, convert, convert, getCardinality, getComponent, getLength, getStringValueCS, getTypedValue, getTypeLabel, isNaN, itemAt, iterate, process, setTypeLabel, subsequence, toString
 
Methods inherited from class net.sf.saxon.value.Value
asItem, asItem, asIterator, asValue, convertJavaObjectToXPath, convertToJava, fromItem, getCanonicalLexicalRepresentation, getIterator, iterate, makeQNameValue, reduce, stringToNumber
 
Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait
 

Constructor Detail

ObjectValue

public ObjectValue()
Default constructor for use in subclasses


ObjectValue

public ObjectValue(Object object)
Constructor

Parameters:
object - the object to be encapsulated

ObjectValue

public ObjectValue(Object object,
                   ExternalObjectType type)
Constructor

Parameters:
object - the object to be encapsulated
type - the type of the external object
Method Detail

setValue

public void setValue(Object value)
Set the value in this object value

Parameters:
value - the external value to be wrapped

copyAsSubType

public AtomicValue copyAsSubType(AtomicType typeLabel)
Create a copy of this atomic value, with a different type label

Specified by:
copyAsSubType in class AtomicValue
Parameters:
typeLabel - the type label of the new copy. The caller is responsible for checking that the value actually conforms to this type.
Returns:
the copied value

getPrimitiveType

public BuiltInAtomicType getPrimitiveType()
Determine the primitive type of the value. This delivers the same answer as getItemType().getPrimitiveItemType(). The primitive types are the 19 primitive types of XML Schema, plus xs:integer, xs:dayTimeDuration and xs:yearMonthDuration, and xs:untypedAtomic. For external objects, the result is AnyAtomicType.

Specified by:
getPrimitiveType in class AtomicValue
Returns:
the primitive type

getItemType

public ItemType getItemType(TypeHierarchy th)
Determine the data type of the items in the expression, if possible

Overrides:
getItemType in class AtomicValue
Parameters:
th - The TypeHierarchy.
Returns:
for the default implementation: AnyItemType (not known)

displayTypeName

public String displayTypeName()
Display the type name for use in error messages

Returns:
the type name

convertPrimitive

public ConversionResult convertPrimitive(BuiltInAtomicType requiredType,
                                         boolean validate,
                                         XPathContext context)
Convert to target data type

Parameters:
requiredType - the required atomic type. This must either be a primitive type, or a built-in type derived from the same primitive type as this atomic value.
validate - true if validation is required. If set to false, the caller guarantees that the value is valid for the target data type, and that further validation is therefore not required. Note that a validation failure may be reported even if validation was not requested.
context - The conversion context to be used. This is required at present only when converting to xs:Name or similar types: it determines the NameChecker to be used.
Returns:
the result of the conversion, if successful. If unsuccessful, the value returned will be a ValidationFailure. The caller must check for this condition. No exception is thrown, instead the exception information will be encapsulated within the ValidationFailure.

getStringValue

public String getStringValue()
Get the value as a String

Specified by:
getStringValue in interface Item
Specified by:
getStringValue in interface ValueRepresentation
Specified by:
getStringValue in class AtomicValue
Returns:
a String representation of the value
See Also:
Item.getStringValueCS()

effectiveBooleanValue

public boolean effectiveBooleanValue()
                              throws XPathException
Get the effective boolean value of the value

Overrides:
effectiveBooleanValue in class AtomicValue
Returns:
true, unless the value is boolean false, numeric zero, or zero-length string
Throws:
XPathException - if any dynamic error occurs evaluating the expression

getObject

public Object getObject()
Get the encapsulated object

Returns:
the Java object that this external object wraps

getSchemaComparable

public Comparable getSchemaComparable()
Description copied from class: AtomicValue
Get a Comparable value that implements the XML Schema ordering comparison semantics for this value. An implementation must be provided for all atomic types.

In the case of data types that are partially ordered, the returned Comparable extends the standard semantics of the compareTo() method by returning the value Value.INDETERMINATE_ORDERING when there is no defined order relationship between two given values. This value is also returned when two values of different types are compared.

Specified by:
getSchemaComparable in class AtomicValue
Returns:
a Comparable that follows XML Schema comparison rules

getXPathComparable

public Object getXPathComparable(boolean ordered,
                                 StringCollator collator,
                                 XPathContext context)
Get an object value that implements the XPath equality and ordering comparison semantics for this value. If the ordered parameter is set to true, the result will be a Comparable and will support a compareTo() method with the semantics of the XPath lt/gt operator, provided that the other operand is also obtained using the getXPathComparable() method. In all cases the result will support equals() and hashCode() methods that support the semantics of the XPath eq operator, again provided that the other operand is also obtained using the getXPathComparable() method. A context argument is supplied for use in cases where the comparison semantics are context-sensitive, for example where they depend on the implicit timezone or the default collation.

Specified by:
getXPathComparable in class AtomicValue
Parameters:
ordered - true if an ordered comparison is required. In this case the result is null if the type is unordered; in other cases the returned value will be a Comparable.
collator -
context - the XPath dynamic evaluation context, used in cases where the comparison is context sensitive @return an Object whose equals() and hashCode() methods implement the XPath comparison semantics with respect to this atomic value. If ordered is specified, the result will either be null if no ordering is defined, or will be a Comparable
Returns:
an Object whose equals() and hashCode() methods implement the XPath comparison semantics with respect to this atomic value. If ordered is specified, the result will either be null if no ordering is defined, or will be a Comparable

equals

public boolean equals(Object other)
Determine if two ObjectValues are equal

Specified by:
equals in class AtomicValue
Parameters:
other - the other value
Returns:
true if the other operand is an atomic value and the two values are equal as defined by the XPath eq operator
Throws:
ClassCastException - if they are not comparable

hashCode

public int hashCode()
Overrides:
hashCode in class Object

convertToJava

public Object convertToJava(Class target,
                            XPathContext context)
                     throws XPathException
Convert to Java object (for passing to external functions)

Overrides:
convertToJava in class Value
Parameters:
target - the required target class
context - the XPath dynamic evaluation context
Returns:
the (boxed) Java object that best represents the XPath value
Throws:
XPathException


Copyright (C) Michael H. Kay. All rights reserved.