net.sf.saxon.functions.DynamicErrorInfo Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of Saxon-HE Show documentation
Show all versions of Saxon-HE Show documentation
The XSLT and XQuery Processor
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2015 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.functions;
import net.sf.saxon.expr.XPathContext;
import net.sf.saxon.lib.ExtensionFunctionCall;
import net.sf.saxon.lib.ExtensionFunctionDefinition;
import net.sf.saxon.lib.NamespaceConstant;
import net.sf.saxon.om.Sequence;
import net.sf.saxon.om.StructuredQName;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.type.BuiltInAtomicType;
import net.sf.saxon.value.*;
import net.sf.saxon.value.StringValue;
import javax.xml.transform.SourceLocator;
/**
* This class implements the extension function saxon:dynamic-error-info(), which underpins the
* variables accessible within saxon:catch such as $err:code etc. This function is not documented
* for direct use by applications, though there is no reason it would not work; instead, calls to
* this function are generated to represent the conventional variables $err:code, $err:description, etc.
* The function has a single argument, which is the local name of the corresponding variable name,
* as a string.
*/
public class DynamicErrorInfo extends ExtensionFunctionDefinition {
private static final StructuredQName qName =
new StructuredQName("", NamespaceConstant.SAXON, "dynamic-error-info");
/**
* Get the function name, as a QName
*
* @return the QName of the function
*/
public StructuredQName getFunctionQName() {
return qName;
}
/**
* Get the minimum number of arguments required by the function
*
* @return the minimum number of arguments that must be supplied in a call to this function
*/
public int getMinimumNumberOfArguments() {
return 1;
}
/**
* Get the maximum number of arguments allowed by the function
*
* @return the maximum number of arguments that may be supplied in a call to this function
*/
public int getMaximumNumberOfArguments() {
return 1;
}
/**
* Get the required types for the arguments of this function, counting from zero
*
* @return the required types of the argument, as defined by the function signature. Normally
* this should be an array of size {@link #getMaximumNumberOfArguments()}; however for functions
* that allow a variable number of arguments, the array can be smaller than this, with the last
* entry in the array providing the required type for all the remaining arguments.
*/
public SequenceType[] getArgumentTypes() {
return new SequenceType[]{SequenceType.SINGLE_STRING};
}
/**
* Get the type of the result of the function
*
* @param suppliedArgumentTypes the static types of the arguments to the function.
* This is provided so that a more precise result type can be returned in the common
* case where the type of the result depends on the type of the first argument. The value
* will be null if the function call has no arguments.
* @return the return type of the function, as defined by its function signature
*/
public SequenceType getResultType(SequenceType[] suppliedArgumentTypes) {
return SequenceType.ANY_SEQUENCE;
}
/**
* Ask whether the result of the function depends on the focus
*
* @return true if the result of the function depends on the context item, position, or size.
* The default implementation returns false. This must be set to true if the function
* makes use of any of these values from the dynamic context.
*/
public boolean dependsOnFocus() {
return true;
}
/**
* Ask whether the function has side-effects. If the function does have side-effects, the optimizer
* will be less aggressive in moving or removing calls to the function. However, calls on functions
* with side-effects can never be guaranteed.
*
* @return true if the function has side-effects (including creation of new nodes, if the
* identity of those nodes is significant). The default implementation returns false.
*/
@Override
public boolean hasSideEffects() {
// return true to prevent loop-lifting out of the try/catch expression: see bug 2181
return true;
}
/**
* Create a call on this function. This method is called by the compiler when it identifies
* a function call that calls this function.
*/
public ExtensionFunctionCall makeCallExpression() {
return new DynamicErrorInfoCall();
}
private static class DynamicErrorInfoCall extends ExtensionFunctionCall {
/**
* Evaluate this function call at run-time
*
* @param context The XPath dynamic evaluation context
* @param arguments The values of the arguments to the function call. Each argument value (which is in general
* a sequence) is supplied in the form of an iterator over the items in the sequence. If required, the
* supplied sequence can be materialized by calling, for example, new SequenceExtent(arguments[i]).
* If the argument is always a singleton, then the single item may be obtained by calling
* arguments[i].next(). The implementation is not obliged to read all the items in each
* SequenceIterator if they are not required to compute the result; but if any SequenceIterator is not read
* to completion, it is good practice to call its close() method.
* @return an iterator over the results of the function. If the result is a single item, it can be
* returned in the form of a {@link net.sf.saxon.tree.iter.SingletonIterator}. If the result is an empty sequence,
* the method should return EmptyIterator.getInstance()
* @throws net.sf.saxon.trans.XPathException
* if a dynamic error occurs during evaluation of the function. The Saxon run-time
* code will add information about the error location.
*/
public Sequence call(XPathContext context, Sequence[] arguments) throws XPathException {
String var = arguments[0].head().getStringValue();
@SuppressWarnings({"ThrowableResultOfMethodCallIgnored"})
XPathException error = context.getCurrentException();
if (error == null) {
return EmptySequence.getInstance();
}
SourceLocator locator = error.getLocator();
if (var.equals("code")) {
StructuredQName errorCodeQName = error.getErrorCodeQName();
if (errorCodeQName == null) {
return EmptySequence.getInstance();
} else {
return new QNameValue(errorCodeQName, BuiltInAtomicType.QNAME);
}
} else if (var.equals("description")) {
return new StringValue(error.getMessage());
} else if (var.equals("value")) {
Sequence value = error.getErrorObject();
if (value == null) {
return EmptySequence.getInstance();
} else {
return value;
}
} else if (var.equals("module")) {
String module = locator == null ? null : locator.getSystemId();
if (module == null) {
return EmptySequence.getInstance();
} else {
return new StringValue(module);
}
} else if (var.equals("line-number")) {
int line = locator == null ? -1 : locator.getLineNumber();
if (line == -1) {
return EmptySequence.getInstance();
} else {
return new Int64Value(line);
}
} else if (var.equals("column-number")) {
int column = locator == null ? -1 : locator.getColumnNumber();
if (column == -1) {
return EmptySequence.getInstance();
} else {
return new Int64Value(column);
}
} else {
return EmptySequence.getInstance();
}
}
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy