net.sf.saxon.expr
Class JPConverter

java.lang.Object
  net.sf.saxon.expr.JPConverter

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

JPConverter.FromBigDecimal, JPConverter.FromBigInteger, JPConverter.FromBoolean, JPConverter.FromBooleanArray, JPConverter.FromByte, JPConverter.FromByteArray, JPConverter.FromCharacter, JPConverter.FromCharArray, JPConverter.FromCollection, JPConverter.FromDate, JPConverter.FromDouble, JPConverter.FromDoubleArray, JPConverter.FromFloat, JPConverter.FromFloatArray, JPConverter.FromInt, JPConverter.FromIntArray, JPConverter.FromLong, JPConverter.FromLongArray, JPConverter.FromObjectArray, JPConverter.FromQName, JPConverter.FromSequenceIterator, JPConverter.FromShort, JPConverter.FromShortArray, JPConverter.FromSource, JPConverter.FromString, JPConverter.FromURI, JPConverter.FromValueRepresentation, JPConverter.WrapExternalObject

public abstract class JPConverter
extends Object
implements Serializable

This class together with its embedded subclasses handles conversion from Java values to XPath values. The general principle is to allocate a specific JPConverter at compile time wherever possible. If there is insufficient type information to make this feasible, a general-purpose JPConverter is allocated, which in turn allocates a more specific converter at run-time to do the actual work.

See Also:

Serialized Form

Nested Class Summary

static class	JPConverter.FromBigDecimal
static class	JPConverter.FromBigInteger
static class	JPConverter.FromBoolean
static class	JPConverter.FromBooleanArray
static class	JPConverter.FromByte
static class	JPConverter.FromByteArray
static class	JPConverter.FromCharacter
static class	JPConverter.FromCharArray
static class	JPConverter.FromCollection
static class	JPConverter.FromDate
static class	JPConverter.FromDouble
static class	JPConverter.FromDoubleArray
static class	JPConverter.FromFloat
static class	JPConverter.FromFloatArray
static class	JPConverter.FromInt
static class	JPConverter.FromIntArray
static class	JPConverter.FromLong
static class	JPConverter.FromLongArray
static class	JPConverter.FromObjectArray
static class	JPConverter.FromQName
static class	JPConverter.FromSequenceIterator
static class	JPConverter.FromShort
static class	JPConverter.FromShortArray
static class	JPConverter.FromSource
static class	JPConverter.FromString
static class	JPConverter.FromURI
static class	JPConverter.FromValueRepresentation
static class	JPConverter.WrapExternalObject

Constructor Summary

JPConverter()

Method Summary

static JPConverter	allocate(Class javaClass, Configuration config) Allocate a Java-to-XPath converter for a given class of Java objects
String	compile(String var, CodeGeneratorService compiler) Generate a Java expression (as text) that can be used to implement this conversion when compiling a query
abstract ValueRepresentation	convert(Object object, XPathContext context) Convert a Java object to an equivalent XPath value
int	getCardinality() Get the cardinality of the XPath value that will result from the conversion
abstract ItemType	getItemType() Get the item type of the XPath value that will result from the conversion

Methods inherited from class java.lang.Object

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

Constructor Detail

JPConverter

public JPConverter()

Method Detail

allocate

public static JPConverter allocate(Class javaClass,
                                   Configuration config)

Allocate a Java-to-XPath converter for a given class of Java objects

Parameters:

javaClass - the class of the Java object to be converted (this may be the static type or the dynamic type, depending when the converter is allocated)

config - the Saxon Configuration

Returns:

a suitable converter

convert

public abstract ValueRepresentation convert(Object object,
                                            XPathContext context)
                                     throws XPathException

Convert a Java object to an equivalent XPath value

Parameters:

object - the java object to be converted

context - the XPath dynamic evaluation context

Returns:

the XPath value resulting from the conversion

Throws:

XPathException - if the conversion is not possible or if it fails

getItemType

public abstract ItemType getItemType()

Get the item type of the XPath value that will result from the conversion

Returns:

the XPath item type

getCardinality

public int getCardinality()

Get the cardinality of the XPath value that will result from the conversion

Returns:

the cardinality of the result

compile

public String compile(String var,
                      CodeGeneratorService compiler)

Generate a Java expression (as text) that can be used to implement this conversion when compiling a query

Parameters:

var - the Java variable that will hold the Java value to be converted

compiler - provides callback services

Returns:

a Java expression (as text) that implements the conversion. The result of the Java expression must be of type ValueRepresentation, and if the cardinality of the converter is exactly one then it must be of type Item.