Class XPathCompiler
To construct an XPathCompiler, use the factory method
Processor.newXPathCompiler()
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An XPathCompiler may be used repeatedly to compile multiple queries. Any changes made to the XPathCompiler (that is, to the static context) do not affect queries that have already been compiled. An XPathCompiler may be used concurrently in multiple threads, but it should not then be modified once initialized.
Changes to an XPathCompiler are cumulative. There is no simple way to reset the XPathCompiler to its initial state; instead, simply create a new XPathCompiler.
- Since:
- 9.0
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionCompile an XPath expression, supplied as a character string.compilePattern
(String source) Compile an XSLT 2.0 pattern, supplied as a character string.void
declareNamespace
(String prefix, String uri) Declare a namespace binding as part of the static context for XPath expressions compiled using this XPathCompilervoid
declareVariable
(QName qname) Declare a variable as part of the static context for XPath expressions compiled using this XPathCompiler.void
declareVariable
(QName qname, ItemType itemType, OccurrenceIndicator occurrences) Declare a variable as part of the static context for XPath expressions compiled using this XPathCompiler.Get the static base URI for XPath expressions compiled using this XPathCompiler.Escape-hatch method to get the underlying static context object used by the implementation.void
Import a schema namespace: that is, add the element and attribute declarations and type definitions contained in a given namespace to the static context for the XPath expression.boolean
Ask whether XPath 1.0 backwards compatibility mode is in force.void
setBackwardsCompatible
(boolean option) Set whether XPath 1.0 backwards compatibility mode is to be used.void
setBaseURI
(URI uri) Set the static base URI for XPath expressions compiled using this XPathCompiler.
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Constructor Details
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XPathCompiler
Protected constructor- Parameters:
processor
- the s9api Processor
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Method Details
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setBackwardsCompatible
public void setBackwardsCompatible(boolean option) Set whether XPath 1.0 backwards compatibility mode is to be used. In backwards compatibility mode, more implicit type conversions are allowed in XPath expressions, for example it is possible to compare a number with a string. The default is false (backwards compatibility mode is off).- Parameters:
option
- true if XPath 1.0 backwards compatibility is to be enabled, false if it is to be disabled.
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isBackwardsCompatible
public boolean isBackwardsCompatible()Ask whether XPath 1.0 backwards compatibility mode is in force.- Returns:
- true if XPath 1.0 backwards compatibility is enabled, false if it is disabled.
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setBaseURI
Set the static base URI for XPath expressions compiled using this XPathCompiler. The base URI is part of the static context, and is used to resolve any relative URIs appearing within an XPath expression, for example a relative URI passed as an argument to the doc() function. If no static base URI is supplied, then the current working directory is used.- Parameters:
uri
- the base URI to be set in the static context. This must be an absolute URI.
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getBaseURI
Get the static base URI for XPath expressions compiled using this XPathCompiler. The base URI is part of the static context, and is used to resolve any relative URIs appearing within an XPath expression, for example a relative URI passed as an argument to the doc() function. If no static base URI has been explicitly set, this method returns null.- Returns:
- the base URI from the static context
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declareNamespace
Declare a namespace binding as part of the static context for XPath expressions compiled using this XPathCompiler- Parameters:
prefix
- The namespace prefix. If the value is a zero-length string, this method sets the default namespace for elements and types.uri
- The namespace URI. It is possible to specify a zero-length string to "undeclare" a namespace; in this case the prefix will not be available for use, except in the case where the prefix is also a zero length string, in which case the absence of a prefix implies that the name is in no namespace.- Throws:
NullPointerException
- if either the prefix or uri is null.
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importSchemaNamespace
Import a schema namespace: that is, add the element and attribute declarations and type definitions contained in a given namespace to the static context for the XPath expression.This method will not cause the schema to be loaded. That must be done separately, using the
SchemaManager
. This method will not fail if the schema has not been loaded (but in that case the set of declarations and definitions made available to the XPath expression is empty). The schema document for the specified namespace may be loaded before or after this method is called.This method does not bind a prefix to the namespace. That must be done separately, using the
declareNamespace(String, String)
method.- Parameters:
uri
- The schema namespace to be imported. To import declarations in a no-namespace schema, supply a zero-length string.- Since:
- 9.1
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declareVariable
Declare a variable as part of the static context for XPath expressions compiled using this XPathCompiler. It is an error for the XPath expression to refer to a variable unless it has been declared. This method declares the existence of the variable, but it does not bind any value to the variable; that is done later, when the XPath expression is evaluated. The variable is allowed to have any type (that is, the required type isitem()*
).- Parameters:
qname
- The name of the variable, expressions as a QName
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declareVariable
public void declareVariable(QName qname, ItemType itemType, OccurrenceIndicator occurrences) throws SaxonApiException Declare a variable as part of the static context for XPath expressions compiled using this XPathCompiler. It is an error for the XPath expression to refer to a variable unless it has been declared. This method declares the existence of the variable, and defines the required type of the variable, but it does not bind any value to the variable; that is done later, when the XPath expression is evaluated.- Parameters:
qname
- The name of the variable, expressed as a QNameitemType
- The required item type of the value of the variableoccurrences
- The allowed number of items in the sequence forming the value of the variable- Throws:
SaxonApiException
- if the requiredType is syntactically invalid or if it refers to namespace prefixes or schema components that are not present in the static context
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compile
Compile an XPath expression, supplied as a character string.- Parameters:
source
- A string containing the source text of the XPath expression- Returns:
- An XPathExecutable which represents the compiled xpath expression object. The XPathExecutable may be run as many times as required, in the same or a different thread. The XPathExecutable is not affected by any changes made to the XPathCompiler once it has been compiled.
- Throws:
SaxonApiException
- if any static error is detected while analyzing the expression
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compilePattern
Compile an XSLT 2.0 pattern, supplied as a character string. The compiled pattern behaves as a boolean expression which, when evaluated in a particular context, returns true if the context node matches the pattern, and false if it does not. An error is reported if there is no context item or it the context item is not a node.- Parameters:
source
- A string conforming to the syntax of XSLT 2.0 patterns- Returns:
- An XPathExecutable representing an expression which evaluates to true when the context node matches the pattern, and false when it does not.
- Throws:
SaxonApiException
- if the pattern contains static errors: for example, if its syntax is incorrect, or if it refers to undeclared variables or namespaces- Since:
- 9.1
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getUnderlyingStaticContext
Escape-hatch method to get the underlying static context object used by the implementation.- Returns:
- the underlying static context object. In the current implementation this will always
be an instance of
IndependentContext
.This method provides an escape hatch to internal Saxon implementation objects that offer a finer and lower-level degree of control than the s9api classes and methods. Some of these classes and methods may change from release to release.
- Since:
- 9.1
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