net.sf.saxon.functions.CollatingFunctionFixed 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) 2018-2022 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.StaticContext;
import net.sf.saxon.expr.XPathContext;
import net.sf.saxon.expr.parser.RetainedStaticContext;
import net.sf.saxon.expr.sort.*;
import net.sf.saxon.lib.NamespaceConstant;
import net.sf.saxon.lib.StringCollator;
import net.sf.saxon.lib.SubstringMatcher;
import net.sf.saxon.trace.ExpressionPresenter;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.type.AtomicType;
import net.sf.saxon.type.BuiltInAtomicType;
import net.sf.saxon.type.ErrorType;
import java.util.Properties;
/**
* Abstract superclass for functions that take an optional collation argument, in which the
* collation is not present as an explicit argument, either because it was defaulted in the
* original function call, or because it has been bound during static analysis.
*/
public abstract class CollatingFunctionFixed extends SystemFunction implements StatefulSystemFunction {
// The absolute collation URI
private String collationName;
// The collation corresponding to this collation name
private StringCollator stringCollator = null;
// The AtomicComparer to be used (not used by all collating functions)
private AtomicComparer atomicComparer = null;
/**
* Ask whether this function needs a collation that can handle substring matching
*
* @return true in the case of functions such as contains() and starts-with() where
* substring matching is required. Returns false by default;
*/
public boolean isSubstringMatchingFunction() {
return false;
}
/**
* Get the collation if known statically, as a StringCollator object
*
* @return a StringCollator. Return null if the collation is not known statically.
*/
public StringCollator getStringCollator() {
return stringCollator;
}
@Override
public void setRetainedStaticContext(RetainedStaticContext retainedStaticContext) {
super.setRetainedStaticContext(retainedStaticContext);
if (collationName == null) {
collationName = retainedStaticContext.getDefaultCollationName();
try {
allocateCollator();
} catch (XPathException e) {
// ignore the failure, it will be reported later
}
}
}
public void setCollationName(String collationName) throws XPathException {
this.collationName = collationName;
allocateCollator();
}
private void allocateCollator() throws XPathException {
stringCollator = getRetainedStaticContext().getConfiguration().getCollation(collationName);
if (stringCollator == null) {
throw new XPathException("Unknown collation " + collationName, "FOCH0002");
}
if (isSubstringMatchingFunction()) {
if (stringCollator instanceof SimpleCollation) {
stringCollator = ((SimpleCollation) stringCollator).getSubstringMatcher();
}
if (!(stringCollator instanceof SubstringMatcher)) {
throw new XPathException("The collation requested for " + getFunctionName().getDisplayName() +
" does not support substring matching", "FOCH0004");
}
}
}
/**
* During static analysis, if types are known and the collation is known, pre-allocate a comparer
* for comparing atomic values. Called by some collating functions during type-checking. The comparer
* that is allocated treats NaN as not equal to NaN.
* @param type0 the type of the first comparand
* @param type1 the type of the second comparand
* @param env the static context
*/
protected void preAllocateComparer(AtomicType type0, AtomicType type1, StaticContext env) {
StringCollator collation = getStringCollator();
if (type0 == ErrorType.getInstance() || type1 == ErrorType.getInstance()) {
// there will be no instances to compare, so we can use any comparer
atomicComparer = EqualityComparer.getInstance();
return;
}
atomicComparer = GenericAtomicComparer.makeAtomicComparer(
(BuiltInAtomicType) type0.getBuiltInBaseType(), (BuiltInAtomicType) type1.getBuiltInBaseType(),
stringCollator, env.makeEarlyEvaluationContext());
}
/**
* Get the pre-allocated atomic comparer, if available
*
* @return the preallocated atomic comparer, or null
*/
public AtomicComparer getPreAllocatedAtomicComparer() {
return atomicComparer;
}
/**
* During evaluation, get the pre-allocated atomic comparer if available, or allocate a new one otherwise
*
* @param context the dynamic evaluation context
* @return the pre-allocated comparer if one is available; otherwise, a newly allocated one, using the specified
* StringCollator for comparing strings
*/
public AtomicComparer getAtomicComparer(XPathContext context) {
if (atomicComparer != null) {
return atomicComparer.provideContext(context);
} else {
return new GenericAtomicComparer(getStringCollator(), context);
}
}
@Override
public void exportAttributes(ExpressionPresenter out) {
if (!collationName.equals(NamespaceConstant.CODEPOINT_COLLATION_URI)) {
out.emitAttribute("collation", collationName);
}
}
@Override
public void importAttributes(Properties attributes) throws XPathException {
String collationName = attributes.getProperty("collation");
if (collationName != null) {
setCollationName(collationName);
}
}
/**
* Make a copy of this SystemFunction. This is required only for system functions such as regex
* functions that maintain state on behalf of a particular caller.
*
* @return a copy of the system function able to contain its own copy of the state on behalf of
* the caller.
*/
@Override
public CollatingFunctionFixed copy() {
SystemFunction copy = SystemFunction.makeFunction(getFunctionName().getLocalPart(), getRetainedStaticContext(), getArity());
if (copy instanceof CollatingFunctionFree) {
try {
copy = ((CollatingFunctionFree) copy).bindCollation(collationName);
} catch (XPathException e) {
throw new AssertionError(e);
}
}
if (copy instanceof CollatingFunctionFixed) {
((CollatingFunctionFixed) copy).collationName = collationName;
((CollatingFunctionFixed) copy).atomicComparer = atomicComparer;
((CollatingFunctionFixed) copy).stringCollator = stringCollator;
return (CollatingFunctionFixed) copy;
}
throw new IllegalStateException();
}
}