/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.scxml;
import java.io.Serializable;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import javax.xml.transform.TransformerException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.commons.scxml.model.TransitionTarget;
import org.apache.xml.utils.PrefixResolver;
import org.apache.xpath.XPath;
import org.apache.xpath.XPathAPI;
import org.apache.xpath.XPathContext;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
/**
* Implementations of builtin functions defined by the SCXML
* specification.
*
* The current version of the specification defines one builtin
* predicate In()
*/
public class Builtin implements Serializable {
/**
* Serial version UID.
*/
private static final long serialVersionUID = 1L;
/**
* Implements the In() predicate for SCXML documents. The method
* name chosen is different since "in" is a reserved token
* in some expression languages.
*
* Does this state belong to the given Set of States.
* Simple ID based comparator, assumes IDs are unique.
*
* @param allStates The Set of State objects to look in
* @param state The State ID to compare with
* @return Whether this State belongs to this Set
*/
public static boolean isMember(final Set allStates,
final String state) {
for (Iterator i = allStates.iterator(); i.hasNext();) {
TransitionTarget tt = (TransitionTarget) i.next();
if (state.equals(tt.getId())) {
return true;
}
}
return false;
}
/**
* Implements the Data() function for Commons SCXML documents, that
* can be used to obtain a node from one of the XML data trees.
* Manifests within "location" attribute of <assign> element,
* for Commons JEXL and Commons EL based documents.
*
* @param namespaces The current document namespaces map at XPath location
* @param data The context Node, though the method accepts an Object
* so error is reported by Commons SCXML, rather
* than the underlying expression language.
* @param path The XPath expression.
* @return The first node matching the path, or null if no nodes match.
*/
public static Node dataNode(final Map namespaces, final Object data,
final String path) {
if (data == null || !(data instanceof Node)) {
Log log = LogFactory.getLog(Builtin.class);
log.error("Data(): Cannot evaluate an XPath expression"
+ " in the absence of a context Node, null returned");
return null;
}
Node dataNode = (Node) data;
NodeList result = null;
try {
if (namespaces == null || namespaces.size() == 0) {
Log log = LogFactory.getLog(Builtin.class);
if (log.isDebugEnabled()) {
log.debug("Turning off namespaced XPath evaluation since "
+ "no namespace information is available for path: "
+ path);
}
result = XPathAPI.selectNodeList(dataNode, path);
} else {
XPathContext xpathSupport = new XPathContext();
PrefixResolver prefixResolver =
new DataPrefixResolver(namespaces);
XPath xpath = new XPath(path, null, prefixResolver,
XPath.SELECT);
int ctxtNode = xpathSupport.getDTMHandleFromNode(dataNode);
result = xpath.execute(xpathSupport, ctxtNode,
prefixResolver).nodelist();
}
} catch (TransformerException te) {
Log log = LogFactory.getLog(Builtin.class);
log.error(te.getMessage(), te);
return null;
}
int length = result.getLength();
if (length == 0) {
Log log = LogFactory.getLog(Builtin.class);
log.warn("Data(): No nodes matching the XPath expression \""
+ path + "\", returning null");
return null;
} else {
if (length > 1) {
Log log = LogFactory.getLog(Builtin.class);
log.warn("Data(): Multiple nodes matching XPath expression \""
+ path + "\", returning first");
}
return result.item(0);
}
}
/**
* A variant of the Data() function for Commons SCXML documents,
* coerced to a Double, a Long or a String, whichever succeeds,
* in that order.
* Manifests within rvalue expressions in the document,
* for Commons JEXL and Commons EL based documents..
*
* @param namespaces The current document namespaces map at XPath location
* @param data The context Node, though the method accepts an Object
* so error is reported by Commons SCXML, rather
* than the underlying expression language.
* @param path The XPath expression.
* @return The first node matching the path, coerced to a String, or null
* if no nodes match.
*/
public static Object data(final Map namespaces, final Object data,
final String path) {
Object retVal = null;
String strVal = SCXMLHelper.getNodeValue(dataNode(namespaces,
data, path));
// try as a double
try {
double d = Double.parseDouble(strVal);
retVal = new Double(d);
} catch (NumberFormatException notADouble) {
// else as a long
try {
long l = Long.parseLong(strVal);
retVal = new Long(l);
} catch (NumberFormatException notALong) {
// fallback to string
retVal = strVal;
}
}
return retVal;
}
/**
* Implements the Data() function for Commons SCXML documents, that
* can be used to obtain a node from one of the XML data trees.
* Manifests within "location" attribute of <assign> element,
* for Commons JEXL and Commons EL based documents.
*
* @param data The context Node, though the method accepts an Object
* so error is reported by Commons SCXML, rather
* than the underlying expression language.
* @param path The XPath expression.
* @return The first node matching the path, or null if no nodes match.
*
* @deprecated Use {@link #dataNode(Map,Object,String)} instead
*/
public static Node dataNode(final Object data, final String path) {
if (data == null || !(data instanceof Node)) {
Log log = LogFactory.getLog(Builtin.class);
log.error("Data(): Cannot evaluate an XPath expression"
+ " in the absence of a context Node, null returned");
return null;
}
Node dataNode = (Node) data;
NodeList result = null;
try {
result = XPathAPI.selectNodeList(dataNode, path);
} catch (TransformerException te) {
Log log = LogFactory.getLog(Builtin.class);
log.error(te.getMessage(), te);
return null;
}
int length = result.getLength();
if (length == 0) {
Log log = LogFactory.getLog(Builtin.class);
log.warn("Data(): No nodes matching the XPath expression \""
+ path + "\", returning null");
return null;
} else {
if (length > 1) {
Log log = LogFactory.getLog(Builtin.class);
log.warn("Data(): Multiple nodes matching XPath expression \""
+ path + "\", returning first");
}
return result.item(0);
}
}
/**
* A variant of the Data() function for Commons SCXML documents,
* coerced to a Double, a Long or a String, whichever succeeds,
* in that order.
* Manifests within rvalue expressions in the document,
* for Commons JEXL and Commons EL based documents..
*
* @param data The context Node, though the method accepts an Object
* so error is reported by Commons SCXML, rather
* than the underlying expression language.
* @param path The XPath expression.
* @return The first node matching the path, coerced to a String, or null
* if no nodes match.
*
* @deprecated Use {@link #data(Map,Object,String)} instead
*/
public static Object data(final Object data, final String path) {
Object retVal = null;
String strVal = SCXMLHelper.getNodeValue(dataNode(data, path));
// try as a double
try {
double d = Double.parseDouble(strVal);
retVal = new Double(d);
} catch (NumberFormatException notADouble) {
// else as a long
try {
long l = Long.parseLong(strVal);
retVal = new Long(l);
} catch (NumberFormatException notALong) {
// fallback to string
retVal = strVal;
}
}
return retVal;
}
/**
* Prefix resolver for XPaths pointing to <data> nodes.
*/
private static class DataPrefixResolver implements PrefixResolver {
/** Cached namespaces. */
private Map namespaces;
/**
* Constructor.
* @param namespaces The prefix to namespace URI map.
*/
private DataPrefixResolver(final Map namespaces) {
this.namespaces = namespaces;
}
/** {@inheritDoc} */
public String getNamespaceForPrefix(final String prefix) {
return (String) namespaces.get(prefix);
}
/** {@inheritDoc} */
public String getNamespaceForPrefix(final String prefix,
final Node nsContext) {
return (String) namespaces.get(prefix);
}
/** {@inheritDoc} */
public String getBaseIdentifier() {
return null;
}
/** {@inheritDoc} */
public boolean handlesNullPrefixes() {
return false;
}
}
}