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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.ma.map;
import net.sf.saxon.expr.Expression;
import net.sf.saxon.expr.parser.RoleDiagnostic;
import net.sf.saxon.om.Genre;
import net.sf.saxon.om.Item;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.transpile.CSharpModifiers;
import net.sf.saxon.type.*;
import net.sf.saxon.value.SequenceType;
/**
* An instance of this class represents a self-reference within a record type, that is the ".."
* construct in a record test such as record(data as xs:string, next? as ..).
* It contains a reference to the containing record type, and delegates matching operations
* to the containing type, but needs to handle operations differently such as conversion to a string
* or alpha-code, or comparison of item types for equality, to avoid going into infinite recursion.
*/
public class SelfReferenceRecordTest extends AnyFunctionType implements TupleType {
private final RecordTest containingType;
/**
* Construct a RecordTest
* @param containingType the record test containing the self-reference
*/
public SelfReferenceRecordTest(RecordTest containingType) {
this.containingType = containingType;
}
/**
* Determine the Genre (top-level classification) of this type
*
* @return the Genre to which this type belongs, specifically {@link Genre#MAP}
*/
@Override
@CSharpModifiers(code = {"public", "override"})
public Genre getGenre() {
return Genre.MAP;
}
/**
* Ask whether this function item type is a map type. In this case function coercion (to the map type)
* will never succeed.
*
* @return true if this FunctionItemType is a map type
*/
@Override
public boolean isMapType() {
return true;
}
/**
* Ask whether this function item type is an array type. In this case function coercion (to the array type)
* will never succeed.
*
* @return true if this FunctionItemType is an array type
*/
@Override
public boolean isArrayType() {
return false;
}
/**
* Get the names of all the fields
*
* @return the names of the fields (in arbitrary order)
*/
@Override
public Iterable getFieldNames() {
return containingType.getFieldNames();
}
/**
* Get the type of a given field
* @param field the name of the field
* @return the type of the field if it is defined, or null otherwise
*/
@Override
public SequenceType getFieldType(String field) {
return containingType.getFieldType(field);
}
/**
* Ask whether a given field is optional
* @param field the name of the field
* @return true if the field is defined as an optional field
*/
@Override
public boolean isOptionalField(String field) {
return containingType.isOptionalField(field);
}
/**
* Ask whether the record type is extensible, that is, whether fields other than those named are permitted
*
* @return true if fields other than the named fields are permitted to appear
*/
@Override
public boolean isExtensible() {
return containingType.isExtensible();
}
/**
* Test whether a given item conforms to this type
*
* @param item The item to be tested
* @param th type hierarchy data
* @return true if the item is an instance of this type; false otherwise
*/
@Override
public boolean matches(Item item, TypeHierarchy th) {
return containingType.matches(item, th);
}
/**
* Get the arity (number of arguments) of this function type
*
* @return the number of argument types in the function signature
*/
public int getArity() {
return 1;
}
/**
* Get the argument types of this map, viewed as a function
*
* @return the list of argument types of this map, viewed as a function
*/
@Override
public SequenceType[] getArgumentTypes() {
// regardless of the key type, a function call on this map can supply any atomic value
return new SequenceType[]{SequenceType.SINGLE_ATOMIC};
}
/**
* Get the result type of this record type, viewed as a function
*
* @return the result type of this record type, viewed as a function
*/
@Override
public SequenceType getResultType() {
return containingType.getResultType();
}
/**
* Get the default priority when this ItemType is used as an XSLT pattern
*
* @return the default priority
*/
@Override
public double getDefaultPriority() {
return 0.5; // Take care here to avoid recursion!
}
/**
* Produce a representation of this type name for use in error messages.
*
* @return a string representation of the type, in notation resembling but not necessarily
* identical to XPath syntax
*/
public String toString() {
return "..";
}
/**
* Return a string representation of this ItemType suitable for use in stylesheet
* export files. This differs from the result of toString() in that it will not contain
* any references to anonymous types. Note that it may also use the Saxon extended syntax
* for union types and record types.
*
* @return the string representation as an instance of the XPath ItemType construct
*/
@Override
@CSharpModifiers(code={"public", "override"})
public String toExportString() {
return "..";
}
/**
* Get an alphabetic code representing the type, or at any rate, the nearest built-in type
* from which this type is derived. The codes are designed so that for any two built-in types
* A and B, alphaCode(A) is a prefix of alphaCode(B) if and only if A is a supertype of B.
*
* @return the alphacode for the nearest containing built-in type
*/
@Override
public String getBasicAlphaCode() {
return "..";
}
/**
* Test whether this function type equals another function type
*/
public boolean equals(Object other) {
return this == other ||
containingType.equals(other) ||
other instanceof SelfReferenceRecordTest
&& containingType.equals(((SelfReferenceRecordTest)other).containingType);
}
/**
* Returns a hash code value for the object.
*/
@Override
public int hashCode() {
// Need to avoid infinite recursion for self-reference fields
return 0x27ca481f;
}
/**
* Determine the relationship of one function item type to another
*
* @return for example {@link Affinity#SUBSUMES}, {@link Affinity#SAME_TYPE}
*/
@Override
public Affinity relationship(FunctionItemType other, TypeHierarchy th) {
return containingType.relationship(other, th);
}
@Override
public Expression makeFunctionSequenceCoercer(Expression exp, RoleDiagnostic role)
throws XPathException {
return new SpecificFunctionType(getArgumentTypes(), getResultType()).makeFunctionSequenceCoercer(exp, role);
}
}
// Copyright (c) 2011-2022 Saxonica Limited