package net.sf.saxon.s9api;
import net.sf.saxon.expr.StaticContext;
import net.sf.saxon.sxpath.IndependentContext;
import net.sf.saxon.sxpath.XPathEvaluator;
import net.sf.saxon.sxpath.XPathExpression;
import net.sf.saxon.sxpath.XPathVariable;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.value.SequenceType;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.Iterator;
/**
* An XPathCompiler object allows XPath queries to be compiled. The compiler holds information that
* represents the static context for an XPath expression.
*
* <p>To construct an XPathCompiler, use the factory method
* {@link Processor#newXPathCompiler}.</p>
*
* <p>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.</p>
*
* <p>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.</p>
*
* @since 9.0
*/
public class XPathCompiler {
private Processor processor;
private IndependentContext env;
//private ArrayList<XPathVariable> declaredVariables = new ArrayList<XPathVariable>();
/**
* Protected constructor
* @param processor the s9api Processor
*/
protected XPathCompiler(Processor processor) {
this.processor = processor;
env = new IndependentContext(processor.getUnderlyingConfiguration());
}
/**
* 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).
*
* @param option true if XPath 1.0 backwards compatibility is to be enabled, false if it is to
* be disabled.
*/
public void setBackwardsCompatible(boolean option) {
env.setBackwardsCompatibilityMode(option);
}
/**
* Ask whether XPath 1.0 backwards compatibility mode is in force.
*
* @return true if XPath 1.0 backwards compatibility is enabled, false if it is disabled.
*/
public boolean isBackwardsCompatible() {
return env.isInBackwardsCompatibleMode();
}
/**
* 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.
*
* @param uri the base URI to be set in the static context. This must be an absolute URI.
*/
public void setBaseURI(URI uri) {
if (!uri.isAbsolute()) {
throw new IllegalArgumentException("Supplied base URI must be absolute");
}
env.setBaseURI(uri.toString());
}
/**
* 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.
*
* @return the base URI from the static context
*/
public URI getBaseURI() {
try {
return new URI(env.getBaseURI());
} catch (URISyntaxException err) {
throw new IllegalStateException(err);
}
}
/**
* Declare a namespace binding as part of the static context for XPath expressions compiled using this
* XPathCompiler
*
* @param prefix The namespace prefix. If the value is a zero-length string, this method sets the default
* namespace for elements and types.
* @param 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.
*/
public void declareNamespace(String prefix, String uri) {
env.declareNamespace(prefix, uri);
}
/**
* 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.
*
* <p>This method will not cause the schema to be loaded. That must be done separately, using the
* {@link 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.</p>
*
* <p>This method does not bind a prefix to the namespace. That must be done separately, using the
* {@link #declareNamespace(String, String)} method.</p>
*
* @param uri The schema namespace to be imported. To import declarations in a no-namespace schema,
* supply a zero-length string.
* @since 9.1
*/
public void importSchemaNamespace(String uri) {
env.getImportedSchemaNamespaces().add(uri);
}
/**
* Say whether undeclared variables are allowed. By default, they are not allowed. When
* undeclared variables are allowed, it is not necessary to predeclare the variables that
* may be used in the XPath expression; instead, a variable is automatically declared when a reference
* to the variable is encountered within the expression.
* @param allow true if undeclared variables are allowed, false if they are not allowed.
* @since 9.2
*/
public void setAllowUndeclaredVariables(boolean allow) {
env.setAllowUndeclaredVariables(allow);
}
/**
* Ask whether undeclared variables are allowed. By default, they are not allowed. When
* undeclared variables are allowed, it is not necessary to predeclare the variables that
* may be used in the XPath expression; instead, a variable is automatically declared when a reference
* to the variable is encountered within the expression.
* @return true if undeclared variables are allowed, false if they are not allowed.
* @since 9.2
*/
public boolean isAllowUndeclaredVariables() {
return env.isAllowUndeclaredVariables();
}
/**
* 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 is <code>item()*</code>).
*
* @param qname The name of the variable, expressions as a QName
*/
public void declareVariable(QName qname) {
env.declareVariable(qname.getNamespaceURI(), qname.getLocalName());
//declaredVariables.add(var);
}
/**
* 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.
*
* @param qname The name of the variable, expressed as a QName
* @param itemType The required item type of the value of the variable
* @param occurrences 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
*/
public void declareVariable(QName qname, ItemType itemType, OccurrenceIndicator occurrences) throws SaxonApiException {
XPathVariable var = env.declareVariable(qname.getNamespaceURI(), qname.getLocalName());
var.setRequiredType(
SequenceType.makeSequenceType(
itemType.getUnderlyingItemType(), occurrences.getCardinality()));
//declaredVariables.add(var);
}
/**
* Compile an XPath expression, supplied as a character string.
*
* @param source A string containing the source text of the XPath expression
* @return 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
*/
public XPathExecutable compile(String source) throws SaxonApiException {
IndependentContext ic = env;
if (ic.isAllowUndeclaredVariables()) {
// self-declaring variables modify the static context. The XPathCompiler must not change state
// as the result of compiling an expression, so we need to copy the static context.
ic = env.copy();
for (Iterator iter = env.iterateExternalVariables(); iter.hasNext();) {
XPathVariable var = (XPathVariable)iter.next();
XPathVariable var2 = ic.declareVariable(var.getVariableQName());
var2.setRequiredType(var.getRequiredType());
}
}
try {
XPathEvaluator eval = new XPathEvaluator(processor.getUnderlyingConfiguration());
eval.setStaticContext(ic);
XPathExpression cexp = eval.createExpression(source);
return new XPathExecutable(cexp, processor, ic);
} catch (XPathException e) {
throw new SaxonApiException(e);
}
}
/**
* 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.
* @param source A string conforming to the syntax of XSLT 2.0 patterns
* @return 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
*/
public XPathExecutable compilePattern(String source) throws SaxonApiException {
try {
XPathEvaluator eval = new XPathEvaluator(processor.getUnderlyingConfiguration());
eval.setStaticContext(env);
XPathExpression cexp = eval.createPattern(source);
return new XPathExecutable(cexp, processor, env);
} catch (XPathException e) {
throw new SaxonApiException(e);
}
}
/**
* Escape-hatch method to get the underlying static context object used by the implementation.
* @return the underlying static context object. In the current implementation this will always
* be an instance of {@link IndependentContext}.
*
* <p>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.</p>
* @since 9.1
*/
public StaticContext getUnderlyingStaticContext() {
return env;
}
}
//
// The contents of this file are subject to the Mozilla Public License Version 1.0 (the "License");
// you may not use this file except in compliance with the License. You may obtain a copy of the
// License at http://www.mozilla.org/MPL/
//
// Software distributed under the License is distributed on an "AS IS" basis,
// WITHOUT WARRANTY OF ANY KIND, either express or implied.
// See the License for the specific language governing rights and limitations under the License.
//
// The Original Code is: all this file
//
// The Initial Developer of the Original Code is Michael H. Kay.
//
// Contributor(s):
//