net.sf.saxon.expr.instruct.ComputedElement Maven / Gradle / Ivy
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2013 Saxonica Limited.
// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// This Source Code Form is "Incompatible With Secondary Licenses", as defined by the Mozilla Public License, v. 2.0.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
package net.sf.saxon.expr.instruct;
import net.sf.saxon.Configuration;
import net.sf.saxon.Controller;
import net.sf.saxon.event.Receiver;
import net.sf.saxon.expr.*;
import net.sf.saxon.expr.parser.ExpressionVisitor;
import net.sf.saxon.expr.parser.PromotionOffer;
import net.sf.saxon.expr.parser.RoleLocator;
import net.sf.saxon.expr.parser.TypeChecker;
import net.sf.saxon.functions.SystemFunctionCall;
import net.sf.saxon.lib.FeatureKeys;
import net.sf.saxon.lib.NamespaceConstant;
import net.sf.saxon.lib.StandardURIChecker;
import net.sf.saxon.lib.Validation;
import net.sf.saxon.om.*;
import net.sf.saxon.pattern.ContentTypeTest;
import net.sf.saxon.pattern.NodeKindTest;
import net.sf.saxon.trace.ExpressionPresenter;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.type.*;
import net.sf.saxon.value.*;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
/**
* An instruction representing an xsl:element element in an XSLT stylesheet,
* or a computed element constructor in XQuery. (In both cases, if the element name
* is expressed as a compile-time expression, then a FixedElement instruction
* is used instead.)
* @see FixedElement
*/
public class ComputedElement extends ElementCreator {
private Expression elementName;
private Expression namespace = null;
private NamespaceResolver nsContext;
private boolean allowNameAsQName;
private ItemType itemType;
/**
* Create an instruction that creates a new element node
*
* @param elementName Expression that evaluates to produce the name of the
* element node as a lexical QName
* @param namespace Expression that evaluates to produce the namespace URI of
* the element node. Set to null if the namespace is to be deduced from the prefix
* of the elementName.
* @param nsContext Saved copy of the static namespace context for the instruction.
* Can be set to null if namespace is supplied. This namespace context
* must resolve the null prefix correctly, based on the different rules for
* XSLT and XQuery.
//* @param defaultNamespace Default namespace to be used if no namespace is supplied and the
//* computed element is a string with no prefix.
* @param validation Required validation mode (e.g. STRICT, LAX, SKIP)
* @param inheritNamespaces true if child elements automatically inherit the namespaces of their parent
* @param schemaType The required schema type for the content
* @param allowQName True if the elementName expression is allowed to return a QNameValue; false if
* it must return a string, and is cast to a string if necessary
* (that is, true in XQuery, false in XSLT).
*/
public ComputedElement(Expression elementName,
Expression namespace,
NamespaceResolver nsContext,
//String defaultNamespace,
SchemaType schemaType,
int validation,
boolean inheritNamespaces,
boolean allowQName) {
this.elementName = elementName;
this.namespace = namespace;
this.nsContext = nsContext;
setValidationAction(validation, schemaType);
preservingTypes = schemaType == null && validation == Validation.PRESERVE;
this.inheritNamespaces = inheritNamespaces;
allowNameAsQName = allowQName;
adoptChildExpression(elementName);
adoptChildExpression(namespace);
}
/**
* Get the expression used to compute the element name
* @return the expression used to compute the element name
*/
public Expression getNameExpression() {
return elementName;
}
/**
* Get the expression used to compute the namespace URI
* @return the expression used to compute the namespace URI
*/
public Expression getNamespaceExpression() {
return namespace;
}
/**
* Get the namespace resolver that provides the namespace bindings defined in the static context
* @return the namespace resolver
*/
public NamespaceResolver getNamespaceResolver() {
return nsContext;
}
/*@NotNull*/
public Expression simplify(ExpressionVisitor visitor) throws XPathException {
elementName = visitor.simplify(elementName);
namespace = visitor.simplify(namespace);
Configuration config = visitor.getConfiguration();
setLazyConstruction(config.getBooleanProperty(FeatureKeys.LAZY_CONSTRUCTION_MODE));
boolean schemaAware = visitor.getExecutable().isSchemaAware();
preservingTypes |= !schemaAware;
final SchemaType schemaType = getSchemaType();
if (schemaType != null) {
itemType = new ContentTypeTest(Type.ELEMENT, schemaType, config, false);
schemaType.analyzeContentExpression(content, Type.ELEMENT, visitor.getStaticContext());
} else if (getValidationAction() == Validation.STRIP || !schemaAware) {
itemType = new ContentTypeTest(Type.ELEMENT, Untyped.getInstance(), config, false);
} else {
// paradoxically, we know less about the type if validation="strict" is specified!
// We know that it won't be untyped, but we have no way of representing that.
itemType = NodeKindTest.ELEMENT;
}
return super.simplify(visitor);
}
/*@NotNull*/
public Expression typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException {
elementName = visitor.typeCheck(elementName, contextItemType);
//adoptChildExpression(elementName);
RoleLocator role = new RoleLocator(RoleLocator.INSTRUCTION, "element/name", 0);
//role.setSourceLocator(this);
if (allowNameAsQName) {
// Can only happen in XQuery
elementName = TypeChecker.staticTypeCheck(elementName,
SequenceType.SINGLE_ATOMIC, false, role, visitor);
TypeHierarchy th = visitor.getConfiguration().getTypeHierarchy();
ItemType supplied = elementName.getItemType(th);
if (th.relationship(supplied, BuiltInAtomicType.STRING) == TypeHierarchy.DISJOINT &&
th.relationship(supplied, BuiltInAtomicType.UNTYPED_ATOMIC) == TypeHierarchy.DISJOINT &&
th.relationship(supplied, BuiltInAtomicType.QNAME) == TypeHierarchy.DISJOINT) {
XPathException de = new XPathException("The name of a constructed element must be a string, QName, or untypedAtomic");
de.setErrorCode("XPTY0004");
de.setIsTypeError(true);
de.setLocator(this);
throw de;
}
} else {
TypeHierarchy th = visitor.getConfiguration().getTypeHierarchy();
if (!th.isSubType(elementName.getItemType(th), BuiltInAtomicType.STRING)) {
elementName = SystemFunctionCall.makeSystemFunction("string", new Expression[]{elementName});
}
}
if (namespace != null) {
namespace = visitor.typeCheck(namespace, contextItemType);
// TODO: not sure there are any circumstances in which this type check can fail
role = new RoleLocator(RoleLocator.INSTRUCTION, "element/namespace", 0);
namespace = TypeChecker.staticTypeCheck(
namespace, SequenceType.SINGLE_STRING, false, role, visitor);
}
if (Literal.isAtomic(elementName)) {
// Check we have a valid lexical QName, whose prefix is in scope where necessary
try {
AtomicValue val = (AtomicValue)((Literal)elementName).getValue();
if (val instanceof StringValue) {
String[] parts = visitor.getConfiguration().getNameChecker().checkQNameParts(val.getStringValueCS());
if (namespace == null) {
String prefix = parts[0];
String uri = getNamespaceResolver().getURIForPrefix(prefix, true);
if (uri == null) {
XPathException se = new XPathException("Prefix " + prefix + " has not been declared");
se.setErrorCode("XPST0081");
se.setIsStaticError(true);
throw se;
}
namespace = new StringLiteral(uri);
}
}
} catch (XPathException e) {
String code = e.getErrorCodeLocalPart();
if (code == null || code.equals("FORG0001")) {
e.setErrorCode(isXSLT() ? "XTDE0820" : "XQDY0074");
} else if (code.equals("XPST0081")) {
e.setErrorCode(isXSLT() ? "XTDE0830" : "XQDY0074");
}
e.maybeSetLocation(this);
e.setIsStaticError(true);
throw e;
}
}
return super.typeCheck(visitor, contextItemType);
}
/*@NotNull*/
public Expression optimize(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException {
elementName = visitor.optimize(elementName, contextItemType);
return super.optimize(visitor, contextItemType);
}
/**
* Copy an expression. This makes a deep copy.
*
* @return the copy of the original expression
*/
/*@NotNull*/
public Expression copy() {
ComputedElement ce = new ComputedElement(
elementName.copy(), (namespace==null ? null : namespace.copy()),
getNamespaceResolver(), /*defaultNamespace,*/ getSchemaType(),
getValidationAction(), inheritNamespaces, allowNameAsQName);
ce.setContentExpression(content.copy());
return ce;
}
/**
* Get the item type of the value returned by this instruction
*
* @return the item type
* @param th the type hierarchy cache
*/
/*@NotNull*/
public ItemType getItemType(TypeHierarchy th) {
if (itemType == null) {
return super.getItemType(th);
}
return itemType;
}
/*@NotNull*/
public Iterator iterateSubExpressions() {
List list = new ArrayList(3);
list.add(content);
list.add(elementName);
if (namespace != null) {
list.add(namespace);
}
return list.iterator();
}
/**
* Get the immediate sub-expressions of this expression, with information about the relationship
* of each expression to its parent expression. Default implementation
* returns a zero-length array, appropriate for an expression that has no
* sub-expressions.
*
* @return an iterator containing the sub-expressions of this expression
*/
@Override
public Iterator iterateSubExpressionInfo() {
List list = new ArrayList(3);
list.add(new SubExpressionInfo(content, true, false, NODE_VALUE_CONTEXT));
list.add(new SubExpressionInfo(elementName, true, false, NODE_VALUE_CONTEXT));
if (namespace != null) {
list.add(new SubExpressionInfo(namespace, true, false, NODE_VALUE_CONTEXT));
}
if (getOnEmpty() != null) {
list.add(new SubExpressionInfo(onEmpty, true, false, NAVIGATION_CONTEXT));
}
return list.iterator();
}
/**
* Replace one subexpression by a replacement subexpression
* @param original the original subexpression
* @param replacement the replacement subexpression
* @return true if the original subexpression is found
*/
public boolean replaceSubExpression(Expression original, Expression replacement) {
boolean found = false;
if (content == original) {
content = replacement;
found = true;
}
if (elementName == original) {
elementName = replacement;
found = true;
}
if (namespace == original) {
namespace = replacement;
found = true;
}
return found;
}
/**
* Offer promotion for subexpressions. The offer will be accepted if the subexpression
* is not dependent on the factors (e.g. the context item) identified in the PromotionOffer.
* By default the offer is not accepted - this is appropriate in the case of simple expressions
* such as constant values and variable references where promotion would give no performance
* advantage. This method is always called at compile time.
*
* @param offer details of the offer, for example the offer to move
* expressions that don't depend on the context to an outer level in
* the containing expression
* @throws net.sf.saxon.trans.XPathException if any error is detected
*/
protected void promoteInst(PromotionOffer offer) throws XPathException {
elementName = doPromotion(elementName, offer);
if (namespace != null) {
namespace = doPromotion(namespace, offer);
}
super.promoteInst(offer);
}
/**
* Check that any elements and attributes constructed or returned by this expression are acceptable
* in the content model of a given complex type. It's always OK to say yes, since the check will be
* repeated at run-time. The process of checking element and attribute constructors against the content
* model of a complex type also registers the type of content expected of those constructors, so the
* static validation can continue recursively.
*/
public void checkPermittedContents(SchemaType parentType, StaticContext env, boolean whole) throws XPathException {
if (parentType instanceof SimpleType || ((ComplexType)parentType).isSimpleContent()) {
String msg = "Elements are not permitted here: the containing element ";
if (parentType instanceof SimpleType) {
if (parentType.isAnonymousType()) {
msg += "is defined to have a simple type";
} else {
msg += "is of simple type " + parentType.getDescription();
}
} else {
msg += "has a complex type with simple content";
}
XPathException err = new XPathException(msg);
err.setIsTypeError(true);
err.setLocator(this);
throw err;
}
// NOTE: we could in principle check that if all the elements permitted in the content of the parentType
// themselves have a simple type (not uncommon, perhaps) then this element must not have element content.
}
/**
* Callback from the superclass ElementCreator to get the nameCode
* for the element name
*
*
*
* @param context The evaluation context (not used)
* @param copiedNode Not applicable to this overload
* @return the name code for the element name
*/
public NodeName getElementName(XPathContext context, NodeInfo copiedNode)
throws XPathException {
Controller controller = context.getController();
assert controller != null;
String prefix;
String localName;
String uri = null;
// name needs to be evaluated at run-time
AtomicValue nameValue = (AtomicValue)elementName.evaluateItem(context);
if (nameValue == null) {
XPathException err1 = new XPathException("Invalid element name (empty sequence)", this);
err1.setErrorCode((isXSLT() ? "XTDE0820" : "XPTY0004"));
err1.setXPathContext(context);
throw dynamicError(this, err1, context);
}
//nameValue = nameValue.getPrimitiveValue();
if (nameValue instanceof StringValue) { // which includes UntypedAtomic
// this will always be the case in XSLT
CharSequence rawName = nameValue.getStringValueCS();
rawName = Whitespace.trimWhitespace(rawName);
try {
String[] parts = controller.getConfiguration().getNameChecker().getQNameParts(rawName);
prefix = parts[0];
localName = parts[1];
} catch (QNameException err) {
String message = "Invalid element name. " + err.getMessage();
if (rawName.length() == 0) {
message = "Supplied element name is a zero-length string";
}
XPathException err1 = new XPathException(message, this);
err1.setErrorCode((isXSLT() ? "XTDE0820" : "XQDY0074"));
err1.setXPathContext(context);
throw dynamicError(this, err1, context);
}
} else if (nameValue instanceof QNameValue && allowNameAsQName) {
// this is allowed in XQuery
localName = ((QNameValue)nameValue).getLocalName();
uri = ((QNameValue)nameValue).getNamespaceURI();
prefix = ((QNameValue)nameValue).getPrefix();
if (prefix.equals("xmlns")) {
XPathException err = new XPathException("Computed element name has prefix xmlns");
err.setErrorCode("XQDY0096");
err.setXPathContext(context);
throw dynamicError(this, err, context);
}
} else {
XPathException err = new XPathException("Computed element name has incorrect type");
err.setErrorCode((isXSLT() ? "XTDE0820" : "XPTY0004"));
err.setIsTypeError(true);
err.setXPathContext(context);
throw dynamicError(this, err, context);
}
if (namespace == null && uri == null) {
// if (prefix.length() == 0) {
// uri = defaultNamespace;
// } else {
uri = nsContext.getURIForPrefix(prefix, true);
if (uri == null) {
XPathException err = new XPathException("Undeclared prefix in element name: " + prefix, this);
err.setErrorCode((isXSLT() ? "XTDE0830" : (prefix.equals("xmlns") ? "XQDY0096" : "XQDY0074")));
err.setXPathContext(context);
throw dynamicError(this, err, context);
}
// }
} else {
if (uri == null) {
if (namespace instanceof StringLiteral) {
uri = ((StringLiteral)namespace).getStringValue();
} else {
uri = namespace.evaluateAsString(context).toString();
if (!StandardURIChecker.getInstance().isValidURI(uri)) {
XPathException de = new XPathException("The value of the namespace attribute must be a valid URI");
de.setErrorCode("XTDE0835");
de.setXPathContext(context);
de.setLocator(this);
throw de;
}
}
}
if (uri.length() == 0) {
// there is a special rule for this case in the specification;
// we force the element to go in the null namespace
prefix = "";
}
if (prefix.equals("xmlns")) {
// this isn't a legal prefix so we mustn't use it
prefix = "x-xmlns";
}
}
if (uri.equals(NamespaceConstant.XMLNS)) {
XPathException err = new XPathException("Cannot create element in namespace " + uri, this);
err.setErrorCode((isXSLT() ? "XTDE0835" : "XQDY0096"));
err.setXPathContext(context);
throw dynamicError(this, err, context);
}
if (uri.equals(NamespaceConstant.XML) != prefix.equals("xml")) {
String message;
if (prefix.equals("xml")) {
message = "When the prefix is 'xml', the namespace URI must be " + NamespaceConstant.XML;
} else {
message = "When the namespace URI is " + NamespaceConstant.XML + ", the prefix must be 'xml'";
}
XPathException err = new XPathException(message, this);
err.setErrorCode((isXSLT() ? "XTDE0835" : "XQDY0096"));
err.setXPathContext(context);
throw dynamicError(this, err, context);
}
return new FingerprintedQName(prefix, uri, localName);
}
/**
* Ask whether the name can be supplied as a QName. In practice this is true for XQuery, false for XSLT
* @return true if the name can be supplied as a QName
*/
public boolean isAllowNameAsQName(){
return allowNameAsQName;
}
public String getNewBaseURI(XPathContext context, NodeInfo copiedNode) {
return getBaseURI();
}
/**
* Callback to output namespace nodes for the new element.
* @param context The execution context
* @param out the Receiver where the namespace nodes are to be written
* @param nameCode The name of the element node being output
* @param copiedNode Where this is a copied node, the node being copied
* @throws XPathException
*/
public void outputNamespaceNodes(XPathContext context, Receiver out, NodeName nameCode, NodeInfo copiedNode)
throws XPathException {
// no action
}
/**
* Get the name of this instruction for diagnostic and tracing purposes
*/
public int getInstructionNameCode() {
return StandardNames.XSL_ELEMENT;
}
/**
* Diagnostic print of expression structure. The abstract expression tree
* is written to the supplied output destination.
*/
public void explain(ExpressionPresenter out) {
out.startElement("computedElement");
out.emitAttribute("validation", Validation.toString(getValidationAction()));
final SchemaType schemaType = getSchemaType();
if (schemaType != null) {
out.emitAttribute("type", schemaType.getDescription());
}
out.startSubsidiaryElement("name");
elementName.explain(out);
out.endSubsidiaryElement();
if (namespace != null) {
out.startSubsidiaryElement("namespace");
namespace.explain(out);
out.endSubsidiaryElement();
}
out.startSubsidiaryElement("content");
content.explain(out);
out.endSubsidiaryElement();
out.endElement();
}
}
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