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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// 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.expr.flwor;
import net.sf.saxon.Configuration;
import net.sf.saxon.event.Outputter;
import net.sf.saxon.expr.*;
import net.sf.saxon.expr.parser.*;
import net.sf.saxon.s9api.Location;
import net.sf.saxon.trace.ExpressionPresenter;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.transpile.CSharpSimpleEnum;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* A "Clause" refers specifically to one of the clauses of a FLWOR expression, for example the "for"
* clause, the "let" clause, the "where" or "order by" clause. (The "return" clause, however, is not
* modelled as a Clause).
*/
public abstract class Clause {
@CSharpSimpleEnum
public enum ClauseName { FOR, LET, WINDOW, GROUP_BY, COUNT, ORDER_BY, WHERE, TRACE, DIAG, FOR_MEMBER}
private Location location;
private PackageData packageData;
private boolean repeated;
/**
* Get the location, which can be used to determine
* the system ID and line number of the clause
*
* @return the location
*/
public Location getLocation() {
return location;
}
/**
* Set the location, which can be used to determine
* the system ID and line number of the clause
*
* @param locationId the location
*/
public void setLocation(Location locationId) {
this.location = locationId;
}
public void setPackageData(PackageData pd) {
this.packageData = pd;
}
public PackageData getPackageData() {
return packageData;
}
public Configuration getConfiguration() {
return packageData.getConfiguration();
}
public void setRepeated(boolean repeated) {
this.repeated = repeated;
}
public boolean isRepeated() {
return repeated;
}
/**
* Create a copy of this clause
*
* @param flwor the new FLWORExpression to contain the copied clause
* @param rebindings the rebinding map
* @return the copied clause
*/
public abstract Clause copy(FLWORExpression flwor, RebindingMap rebindings);
/**
* Optimize any expressions contained within this clause
*
* @param visitor the ExpressionVisitor, providing access to static context information
* @param contextItemType the type of the context item
* @throws XPathException if any error is detected
*/
public void optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) throws XPathException {
}
/**
* Type-check any expression contained within this clause
*
*
* @param visitor the ExpressionVisitor, providing access to static context information
* @param contextInfo static information about the dynamic context
* @throws XPathException if any error is detected
*/
public void typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException {
}
/**
* Get a pull-mode tuple stream that implements the functionality of this clause, taking its
* input from another tuple stream which this clause modifies
*
* @param base the input tuple stream
* @param context the dynamic evaluation context
* @return the output tuple stream
*/
public abstract TuplePull getPullStream(TuplePull base, XPathContext context);
/**
* Get a push-mode tuple stream that implements the functionality of this clause, supplying its
* output to another tuple stream
*
* @param destination the output tuple stream
* @param output the destination for the result
* @param context the dynamic evaluation context
* @return the push tuple stream that implements the functionality of this clause of the FLWOR
* expression
*/
public abstract TuplePush getPushStream(TuplePush destination, Outputter output, XPathContext context);
/**
* Process the subexpressions of this clause
*
* @param processor the expression processor used to process the subexpressions
* @throws XPathException if any error is detected
*/
public abstract void processOperands(OperandProcessor processor) throws XPathException;
/**
* Diagnostic print of expression structure. The abstract expression tree
* is written to the supplied output destination.
*
* @param out the expression presenter used to display the structure
* @throws XPathException if any error occurs
*/
public abstract void explain(ExpressionPresenter out) throws XPathException;
/**
* Get the variables bound by this clause
*
* @return the variable bindings
*/
public LocalVariableBinding[] getRangeVariables() {
return new LocalVariableBinding[0];
}
/**
* Build a list of all references to a variables declared in this clause
*
* @param visitor the expression visitor
* @param binding a variable declared in this clause
* @param refs the list of variable references, initially empty, to which the method will append
*/
public void gatherVariableReferences(final ExpressionVisitor visitor, Binding binding, List refs) {
}
/**
* Determine whether the clause contains a reference to a local variable binding that cannot be inlined
*
* @param binding the binding for the local variable in question
* @return true if this clause uses the variable in a way that does not permit inlining
*/
public boolean containsNonInlineableVariableReference(Binding binding) {
return false;
}
/**
* Supply improved type information to the expressions that contain references to the variables declared in this clause
*
* @param visitor the expression visitor
* @param references the list of variable references
* @param returnExpr the expression in the return clause
*/
public void refineVariableType(final ExpressionVisitor visitor, List references, Expression returnExpr) {
}
/**
* Collect information about the navigation paths followed by this clause, for document projection purposes
*
* @param pathMap the path map in which the data is to be collected
* @param pathMapNodeSet the path map node set representing the paths to the context item
*/
public abstract void addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet);
/**
* Get a keyword identifying what kind of clause this is
*
* @return the kind of clause
*/
public abstract ClauseName getClauseKey();
/**
* Get a short string representation of the clause
* @return a recognizable string
*/
public String toShortString() {
return toString();
}
/**
* Get information for inclusion in trace output
*
* @return a map containing the properties to be output
*/
public Map getTraceInfo() {
LocalVariableBinding[] vars = getRangeVariables();
if (vars.length == 0) {
return Collections.emptyMap();
} else {
Map info = new HashMap<>(1);
info.put("var", "$" + vars[0].getVariableQName().getDisplayName());
return info;
}
}
}