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eXist-db NoSQL Database Core
/*
* 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.lang.reflect.AccessibleObject;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.List;
import org.exist.dom.QName;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.JavaObjectValue;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.Type;
/**
* A special function call to a Java method or constructor.
*
* This class handles all function calls who's namespace URI
* starts with "java:".
*
* @author Wolfgang Meier
*/
public class JavaCall extends Function {
private final QName qname;
private String name;
private Class myClass = null;
private List candidateMethods = new ArrayList<>(5);
/**
* Create new call on the Java method or constructor identified by the QName.
*
* @param context current context
* @param qname the name of the function
* @throws XPathException in case of a static error
*/
public JavaCall(XQueryContext context, QName qname) throws XPathException {
super(context, null);
this.qname = qname;
String namespaceURI = context.getURIForPrefix(qname.getPrefix());
if (!namespaceURI.startsWith("java:"))
{throw new XPathException(this,
"Internal error: prefix "
+ qname.getPrefix()
+ " does not "
+ "resolve to a Java class");}
namespaceURI = namespaceURI.substring("java:".length());
try {
LOG.debug("Trying to find class {}", namespaceURI);
myClass = Class.forName(namespaceURI);
} catch (final ClassNotFoundException e) {
throw new XPathException(this, "Class: " + namespaceURI + " not found", e);
}
name = qname.getLocalPart();
// convert hyphens into camelCase
if (name.indexOf('-') > 0) {
final StringBuilder buf = new StringBuilder();
boolean afterHyphen = false;
char ch;
for (int i = 0; i < name.length(); i++) {
ch = name.charAt(i);
if (ch == '-')
{afterHyphen = true;}
else {
if (afterHyphen) {
buf.append(Character.toUpperCase(ch));
afterHyphen = false;
} else
{buf.append(ch);}
}
}
name = buf.toString();
LOG.debug("converted method name to {}", name);
}
}
/* (non-Javadoc)
* @see org.exist.xquery.Function#getName()
*/
public QName getName() {
return qname;
}
@Override
public Cardinality getCardinality() {
return Cardinality.ZERO_OR_MORE;
}
/* (non-Javadoc)
* @see org.exist.xquery.Function#setArguments(java.util.List)
*/
public void setArguments(List arguments) throws XPathException {
final int argCount = arguments.size();
steps.addAll(arguments);
// search for candidate methods matching the given number of arguments
if ("new".equals(name)) {
final Constructor[] constructors = myClass.getConstructors();
for (final Constructor constructor : constructors) {
if (Modifier.isPublic(constructor.getModifiers())) {
final Class paramTypes[] = constructor.getParameterTypes();
if (paramTypes.length == argCount) {
LOG.debug("Found constructor {}", constructor.toString());
candidateMethods.add(constructor);
}
}
}
if (candidateMethods.size() == 0) {
final String message = "no constructor found with " + argCount + " arguments";
throw new XPathException(this,
message,
new NoSuchMethodException(message));
}
} else {
final Method[] methods = myClass.getMethods();
for (final Method method : methods) {
if (Modifier.isPublic(method.getModifiers())
&& method.getName().equals(name)) {
final Class paramTypes[] = method.getParameterTypes();
if (Modifier.isStatic(method.getModifiers())) {
if (paramTypes.length == argCount) {
LOG.debug("Found static method {}", method.toString());
candidateMethods.add(method);
}
} else {
if (paramTypes.length == argCount - 1) {
LOG.debug("Found method {}", method.toString());
candidateMethods.add(method);
}
}
}
}
if (candidateMethods.size() == 0) {
final String message = "no method matches " + name + " with " + argCount + " arguments";
throw new XPathException(this,
message,
new NoSuchMethodException(message));
}
}
}
/* (non-Javadoc)
* @see org.exist.xquery.Function#analyze(org.exist.xquery.AnalyzeContextInfo)
*/
public void analyze(AnalyzeContextInfo contextInfo) throws XPathException {
}
/* (non-Javadoc)
* @see org.exist.xquery.Expression#eval(org.exist.xquery.value.Sequence, org.exist.xquery.value.Item)
*/
public Sequence eval(Sequence contextSequence, Item contextItem) throws XPathException {
if (context.getProfiler().isEnabled()) {
context.getProfiler().start(this);
context.getProfiler().message(this, Profiler.DEPENDENCIES, "DEPENDENCIES", Dependency.getDependenciesName(this.getDependencies()));
if (contextSequence != null)
{context.getProfiler().message(this, Profiler.START_SEQUENCES, "CONTEXT SEQUENCE", contextSequence);}
if (contextItem != null)
{context.getProfiler().message(this, Profiler.START_SEQUENCES, "CONTEXT ITEM", contextItem.toSequence());}
}
// get the actual arguments
final Sequence args[] = getArguments(contextSequence, contextItem);
AccessibleObject bestMethod = candidateMethods.get(0);
int conversionPrefs[] = getConversionPreferences(bestMethod, args);
for (AccessibleObject nextMethod : candidateMethods) {
int prefs[] = getConversionPreferences(nextMethod, args);
for (int j = 0; j < prefs.length; j++) {
if (prefs[j] < conversionPrefs[j]) {
bestMethod = nextMethod;
conversionPrefs = prefs;
break;
}
}
}
// LOG.debug("calling method " + bestMethod.toString());
Class paramTypes[] = null;
boolean isStatic = true;
if (bestMethod instanceof Constructor)
{paramTypes = ((Constructor) bestMethod).getParameterTypes();}
else {
paramTypes = ((Method) bestMethod).getParameterTypes();
isStatic = Modifier.isStatic(((Method) bestMethod).getModifiers());
}
final Object[] params = new Object[isStatic ? args.length : args.length - 1];
if (isStatic) {
for (int i = 0; i < args.length; i++) {
params[i] = args[i].toJavaObject(paramTypes[i]);
}
} else {
for (int i = 1; i < args.length; i++) {
params[i - 1] = args[i].toJavaObject(paramTypes[i - 1]);
}
}
Sequence result;
if (bestMethod instanceof Constructor) {
try {
final Object object = ((Constructor) bestMethod).newInstance(params);
result = new JavaObjectValue(object);
} catch (final IllegalArgumentException e) {
throw new XPathException(this,
"illegal argument to constructor "
+ bestMethod.toString()
+ ": "
+ e.getMessage(),
e);
} catch (final Exception e) {
if (e instanceof XPathException)
{throw (XPathException) e;}
else
{throw new XPathException(this,
"exception while calling constructor "
+ bestMethod.toString()
+ ": "
+ e.getMessage(),
e);}
}
} else {
try {
Object invocationResult;
if (isStatic)
{invocationResult = ((Method) bestMethod).invoke(null, params);}
else {
invocationResult =
((Method) bestMethod).invoke(
args[0].toJavaObject(myClass),
params);
}
result = XPathUtil.javaObjectToXPath(invocationResult, getContext());
} catch (final IllegalArgumentException e) {
throw new XPathException(this,
"illegal argument to method "
+ bestMethod.toString()
+ ": "
+ e.getMessage(),
e);
} catch (final Exception e) {
if (e instanceof XPathException)
{throw (XPathException) e;}
else
{throw new XPathException(this,
"exception while calling method "
+ bestMethod.toString()
+ ": "
+ e.getMessage(),
e);}
}
}
if (context.getProfiler().isEnabled())
{context.getProfiler().end(this, "", result);}
if (result==null) {result = Sequence.EMPTY_SEQUENCE;}
return result;
}
/* (non-Javadoc)
* @see org.exist.xquery.Function#returnsType()
*/
public int returnsType() {
return Type.ITEM;
}
private int[] getConversionPreferences(AccessibleObject method, Sequence[] args) {
final int prefs[] = new int[args.length];
Class paramTypes[] = null;
boolean isStatic = true;
if (method instanceof Constructor)
{paramTypes = ((Constructor) method).getParameterTypes();}
else {
paramTypes = ((Method) method).getParameterTypes();
isStatic = Modifier.isStatic(((Method) method).getModifiers());
if (!isStatic) {
Class nonStaticTypes[] = new Class[paramTypes.length + 1];
nonStaticTypes[0] = myClass;
System.arraycopy(paramTypes, 0, nonStaticTypes, 1, paramTypes.length);
paramTypes = nonStaticTypes;
}
}
for (int i = 0; i < args.length; i++) {
prefs[i] = args[i].conversionPreference(paramTypes[i]);
}
return prefs;
}
}
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