chore(py-script-engine): add new function to read function parameters

src/main/java/org/topbraid/shacl/py/GraalPyScriptEngine.java

@@ -1,8 +1,7 @@
 package org.topbraid.shacl.py;
 
-import org.apache.jena.query.QuerySolution;
-import org.apache.jena.rdf.model.Resource;
 import org.graalvm.polyglot.Context;
+import org.topbraid.shacl.py.model.PyTermFactory;
 
 import javax.script.ScriptException;
 
@@ -15,12 +14,19 @@ public class GraalPyScriptEngine extends PyScriptEngineImpl {
 
     public GraalPyScriptEngine() {
         initEngine();
-        // TODO implement
+        context.getPolyglotBindings().putMember("PyTermFactory", new PyTermFactory());
+        context.eval("python",
+                """
+                        import polyglot\s
+                        py_tf = polyglot.import_value('PyTermFactory')
+                        """);
+        context.eval("python", ARGS_FUNCTION);
     }
 
     @Override
     public void initEngine() {
         this.context = Context.newBuilder()
+                .allowAllAccess(true)
                 .option("engine.WarnInterpreterOnly", "false")
                 .build();
         if (this.context == null) {
@@ -33,33 +39,17 @@ public Object eval(String expr) throws ScriptException {
         return context.eval("python", expr);
     }
 
-    @Override
-    public void executeLibraries(Resource exec) throws Exception {
-        // TODO implement
-    }
-
-    @Override
-    public void executeScriptFromURL(String url) throws Exception {
-        // TODO implement
-    }
-
     @Override
     public Object get(String varName) {
         return context.getBindings("python").getMember(varName);
     }
 
-    @Override
-    public Object invokeFunction(String functionName, QuerySolution bindings) throws ScriptException, NoSuchMethodException {
-        return null;
-        // TODO implement
-    }
-
     public final Context getContext() {
         return context;
     }
 
     @Override
-    public Object invokeFunctionOrdered(String functionName, Object[] args) throws ScriptException, NoSuchMethodException {
+    public Object invokeFunctionOrdered(String functionName, Object[] args) {
         return context.getBindings("python").getMember(functionName).execute(args);
     }
 

src/main/java/org/topbraid/shacl/py/PyGraph.java

@@ -0,0 +1,106 @@
+/*
+ *  Licensed 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.
+ *
+ *  See the NOTICE file distributed with this work for additional
+ *  information regarding copyright ownership.
+ */
+package org.topbraid.shacl.py;
+
+import org.apache.jena.graph.Graph;
+import org.apache.jena.graph.Node;
+import org.apache.jena.graph.Triple;
+import org.apache.jena.util.iterator.ExtendedIterator;
+import org.topbraid.jenax.util.ExceptionUtil;
+import org.topbraid.shacl.js.ScriptEngine;
+import org.topbraid.shacl.py.model.PyFactory;
+import org.topbraid.shacl.py.model.PyTriple;
+import org.topbraid.shacl.util.FailureLog;
+
+import java.util.HashSet;
+import java.util.Set;
+
+public class PyGraph {
+
+    protected ScriptEngine engine;
+    private Graph graph;
+    private Set<PyTripleIterator> openIterators = new HashSet<>();
+
+    public PyGraph(Graph graph, ScriptEngine engine) {
+        this.engine = engine;
+        this.graph = graph;
+    }
+
+    public void close() {
+        if (!openIterators.isEmpty()) {
+            FailureLog.get().logWarning("Python graph session ended but " + openIterators.size() + " iterators have not been closed. Make sure to close them programmatically to avoid resource leaks and locking problems.");
+        }
+        closeIterators();
+    }
+
+    public void closeIterators() {
+        for (PyTripleIterator stream : openIterators) {
+            stream.closeIterator();
+        }
+        openIterators.clear();
+    }
+
+    public Graph getGraph() {
+        return graph;
+    }
+
+    public PyTripleIterator find(Object subjectSOM, Object predicateSOM, Object objectSOM) {
+        Node subject = PyFactory.getNode(subjectSOM);
+        Node predicate = PyFactory.getNode(predicateSOM);
+        Node object = PyFactory.getNode(objectSOM);
+        ExtendedIterator<Triple> it = getGraph().find(subject, predicate, object);
+        PyTripleIterator pyit = new PyTripleIterator(it);
+        openIterators.add(pyit);
+        return pyit;
+    }
+
+    public Object query() {
+        try {
+            return engine.invokeFunctionOrdered("RDFQuery", new Object[]{this});
+        } catch (Exception ex) {
+            throw ExceptionUtil.throwUnchecked(ex);
+        }
+    }
+
+    public class PyTripleIterator {
+
+        private ExtendedIterator<Triple> it;
+
+        PyTripleIterator(ExtendedIterator<Triple> it) {
+            this.it = it;
+        }
+
+        public void close() {
+            closeIterator();
+            openIterators.remove(this);
+        }
+
+        void closeIterator() {
+            it.close();
+        }
+
+        public PyTriple next() {
+            if (it.hasNext()) {
+                Triple triple = it.next();
+                return PyFactory.asPyTriple(triple);
+            } else {
+                close();
+                return null;
+            }
+        }
+    }
+}

src/main/java/org/topbraid/shacl/py/PyScriptEngineImpl.java

@@ -24,22 +24,15 @@ public abstract class PyScriptEngineImpl implements ScriptEngine {
     protected final static String ARGS_FUNCTION_NAME = "get_args";
 
     protected final static String ARGS_FUNCTION = "def " + ARGS_FUNCTION_NAME + "(func_str): \n" +
-            "\t start_idx = func_str.find('(') + 1\n" +
-            "\t end_idx = func_str.find(')', start_idx)\n" +
-            "\t if start_idx != -1 and end_idx != -1:\n" +
-            "\t\t params_str = func_str[start_idx:end_idx]\n" +
-            "\t\t args_list = [arg.strip() for arg in params_str.split(',')]\n" +
-            "\t\t return args_list\n" +
-            "\t else:\n" +
+            "\t start_idx = func_str.find('(') + 1 \n" +
+            "\t end_idx = func_str.find(')', start_idx) \n" +
+            "\t if start_idx != -1 and end_idx != -1: \n" +
+            "\t\t params_str = func_str[start_idx:end_idx] \n" +
+            "\t\t args_list = [arg.strip() for arg in params_str.split(',')] \n" +
+            "\t\t return args_list \n" +
+            "\t else: \n" +
             "\t\t return []";
 
-    // Copied from https://davidwalsh.name/javascript-arguments
-    protected final static String ARGS_FUNCTION_2 =
-            "def " + ARGS_FUNCTION_NAME + "(funcString): \n" +
-                    "\t func_code = func.__code__ \n" +
-                    "\t args_list = func_code.co_varnames[:func_code.co_argcount]\n" +
-                    "\t return args_list\n";
-
     public static final String DASH_PY = "http://datashapes.org/py/dash.py";
 
     public static final String RDFQUERY_PY = "http://datashapes.org/py/rdfquery.py";
@@ -114,6 +107,7 @@ public Object invokeFunction(String functionName, QuerySolution bindings) throws
     public abstract void put(String varName, Object value);
 
     protected Reader createScriptReader(String url) throws Exception {
+        // TODO replace dash.js and rdfquery.js with python versions
         if (DASH_PY.equals(url)) {
             return new InputStreamReader(GraalPyScriptEngine.class.getResourceAsStream("/js/dash.js"));
         } else if (RDFQUERY_PY.equals(url)) {
@@ -133,7 +127,6 @@ private List<String> getFunctionParameters(String functionName) throws ScriptExc
             throw new ScriptException("Cannot find Python function \"" + functionName + "\"");
         }
         try {
-            //String funcString = what.toString();
             String funcString = ((Value) what).getSourceLocation().getCharacters().toString();
             Object result = this.invokeFunctionOrdered(ARGS_FUNCTION_NAME, Collections.singletonList(funcString).toArray());
             List<String> results = ScriptEngineUtil.asArray(result).stream().map(Object::toString).collect(Collectors.toList());
@@ -143,4 +136,5 @@ private List<String> getFunctionParameters(String functionName) throws ScriptExc
             throw new ScriptException(ex);
         }
     }
+
 }