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/*
* eXist-db Open Source Native XML Database
* Copyright (C) 2001 The eXist-db Authors
*
* [email protected]
* http://www.exist-db.org
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
package org.exist.xquery;
import java.util.*;
import org.exist.dom.QName;
import org.exist.xquery.value.Sequence;
import javax.annotation.Nullable;
/**
* Abstract base class for an {@link org.exist.xquery.InternalModule}.
* Functions are defined in an array of {@link org.exist.xquery.FunctionDef}, which
* is passed to the constructor. A single implementation class
* can be registered for more than one function signature, given that the signatures differ
* in name or the number of expected arguments. It is thus possible to implement
* similar XQuery functions in one single class.
*
* @author Wolfgang Meier
* @author ljo
*
*/
public abstract class AbstractInternalModule implements InternalModule {
public static class FunctionComparator implements Comparator {
@Override
public int compare(final FunctionDef o1, final FunctionDef o2) {
return o1.getSignature().getFunctionId().compareTo(o2.getSignature().getFunctionId());
}
}
protected final FunctionDef[] mFunctions;
protected final boolean ordered;
private final Map> parameters;
protected final Map mGlobalVariables = new HashMap<>();
public AbstractInternalModule(final FunctionDef[] functions,
final Map> parameters) {
this(functions, parameters, false);
}
public AbstractInternalModule(final FunctionDef[] functions,
final Map> parameters,
final boolean functionsOrdered) {
this.mFunctions = functions;
this.ordered = functionsOrdered;
this.parameters = parameters;
}
@Override
public boolean isInternalModule() {
return true;
}
/**
* Get a parameter.
*
* @param paramName the name of the parameter
*
* @return the value of tyhe parameter
*/
protected List getParameter(final String paramName) {
return parameters.get(paramName);
}
@Override
public void setContextItem(final Sequence contextItem) {
// not used for internal modules
}
@Override
public boolean isReady() {
return true; // internal modules don't need to be compiled
}
@Override
public FunctionSignature[] listFunctions() {
final FunctionSignature signatures[] = new FunctionSignature[mFunctions.length];
for (int i = 0; i < signatures.length; i++) {
signatures[i] = mFunctions[i].getSignature();
}
return signatures;
}
@Override
public Iterator getSignaturesForFunction(final QName qname) {
final List signatures = new ArrayList<>(2);
for (FunctionDef mFunction : mFunctions) {
final FunctionSignature signature = mFunction.getSignature();
if (signature.getName().compareTo(qname) == 0) {
signatures.add(signature);
}
}
return signatures.iterator();
}
@Override
public FunctionDef getFunctionDef(QName qname, int arity) {
final FunctionId id = new FunctionId(qname, arity);
if (ordered) {
return binarySearch(id);
} else {
for (FunctionDef mFunction : mFunctions) {
if (id.compareTo(mFunction.getSignature().getFunctionId()) == 0) {
return mFunction;
}
}
}
return null;
}
private FunctionDef binarySearch(final FunctionId id) {
int low = 0;
int high = mFunctions.length - 1;
while (low <= high) {
final int mid = (low + high) >>> 1;
final FunctionDef midVal = mFunctions[mid];
final int cmp = midVal.getSignature().getFunctionId().compareTo(id);
if (cmp < 0) {
low = mid + 1;
} else if (cmp > 0) {
high = mid - 1;
} else {
return midVal; // key found
}
}
return null; // key not found.
}
@Override
public List getFunctionsByName(final QName qname) {
final List funcs = new ArrayList<>();
for (FunctionDef mFunction : mFunctions) {
final FunctionSignature sig = mFunction.getSignature();
if (sig.getName().compareTo(qname) == 0) {
funcs.add(sig);
}
}
return funcs;
}
public Iterator getGlobalVariables() {
return mGlobalVariables.keySet().iterator();
}
/**
* Declares a variable defined by the module.
*
* NOTE: this should not be called from the constructor of a module
* otherwise when {@link #reset(XQueryContext, boolean)} is called
* with {@code keepGlobals = false}, the variables will be removed
* from the module. Which means they will not be available
* for subsequent re-executions of a cached XQuery.
* Instead, module level variables should be initialised
* in {@link #prepare(XQueryContext)}.
*
* @param qname The name of the variable
* @param value The Java value of the variable, will be converted to an XDM type.
*
* @return the variable
*/
@Override
public Variable declareVariable(final QName qname, final Object value) throws XPathException {
final Sequence val = XPathUtil.javaObjectToXPath(value, null);
Variable var = mGlobalVariables.get(qname);
if (var == null){
var = new VariableImpl(qname);
mGlobalVariables.put(qname, var);
}
var.setValue(val);
return var;
}
/**
* Declares a variable defined by the module.
*
* NOTE: this should not be called from the constructor of a module
* otherwise when {@link #reset(XQueryContext, boolean)} is called
* with {@code keepGlobals = false}, the variables will be removed
* from the module. Which means they will not be available
* for subsequent re-executions of a cached XQuery.
* Instead, module level variables should be initialised
* in {@link #prepare(XQueryContext)}.
*
* @param var The variable
*
* @return the variable
*/
@Override
public Variable declareVariable(final Variable var) {
mGlobalVariables.put(var.getQName(), var);
return var;
}
@Override
@Nullable public Variable resolveVariable(final QName qname) throws XPathException {
return resolveVariable(null, qname);
}
@Override
@Nullable public Variable resolveVariable(@Nullable final AnalyzeContextInfo contextInfo, final QName qname) throws XPathException {
return mGlobalVariables.get(qname);
}
@Override
public boolean isVarDeclared(final QName qname) {
return mGlobalVariables.get(qname) != null;
}
@Override
public void reset(final XQueryContext context) {
//Nothing to do
}
@Override
public void reset(final XQueryContext xqueryContext, final boolean keepGlobals) {
// call deprecated method for backwards compatibility
reset(xqueryContext);
if (!keepGlobals) {
mGlobalVariables.clear();
}
}
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