]> gerrit.simantics Code Review - simantics/platform.git/blobdiff - bundles/org.simantics.scl.db/src/org/simantics/scl/db/SCLFunctions.java
Improve utilities for invoking SCL from Java
[simantics/platform.git] / bundles / org.simantics.scl.db / src / org / simantics / scl / db / SCLFunctions.java
index 76891be980942418f998c3878991c1bc81b2d016..e20dfc471ad9ea28831463f00bc9bfc220d8704a 100644 (file)
-package org.simantics.scl.db;\r
-\r
-import java.io.IOException;\r
-\r
-import org.simantics.Simantics;\r
-import org.simantics.db.ReadGraph;\r
-import org.simantics.db.Resource;\r
-import org.simantics.db.VirtualGraph;\r
-import org.simantics.db.WriteGraph;\r
-import org.simantics.db.common.procedure.adapter.TransientCacheAsyncListener;\r
-import org.simantics.db.common.request.BinaryRead;\r
-import org.simantics.db.common.request.DelayedWriteRequest;\r
-import org.simantics.db.common.request.ReadRequest;\r
-import org.simantics.db.common.request.WriteRequest;\r
-import org.simantics.db.common.request.WriteResultRequest;\r
-import org.simantics.db.exception.DatabaseException;\r
-import org.simantics.db.layer0.util.Layer0Utils;\r
-import org.simantics.db.layer0.variable.Variables;\r
-import org.simantics.db.request.Read;\r
-import org.simantics.db.service.ClusterControl;\r
-import org.simantics.db.service.SerialisationSupport;\r
-import org.simantics.db.service.VirtualGraphSupport;\r
-import org.simantics.layer0.utils.triggers.IActivationManager;\r
-import org.simantics.scl.runtime.SCLContext;\r
-import org.simantics.scl.runtime.function.Function;\r
-import org.simantics.scl.runtime.function.Function1;\r
-import org.simantics.scl.runtime.tuple.Tuple0;\r
-import org.simantics.utils.DataContainer;\r
-\r
-@SuppressWarnings({"rawtypes", "unchecked"})\r
-public class SCLFunctions {\r
-\r
-    public static final String GRAPH = "graph";\r
-\r
-    public static <T> T safeExec(final Function f) {\r
-        try {\r
-            return (T)f.apply(Tuple0.INSTANCE);\r
-        } catch (Throwable t) {\r
-            t.printStackTrace();\r
-            return null;\r
-        }\r
-    }\r
-    \r
-    public static void asyncRead(final Function f) throws DatabaseException {\r
-        final SCLContext context = SCLContext.getCurrent();\r
-        Object graph = context.get(GRAPH);\r
-        if (graph != null) {\r
-            f.apply(Tuple0.INSTANCE);\r
-        } else {\r
-            Simantics.getSession().asyncRequest(new ReadRequest() {\r
-                @Override\r
-                public void run(ReadGraph graph) throws DatabaseException {\r
-                    SCLContext.push(context);\r
-                    ReadGraph oldGraph = (ReadGraph)context.put(GRAPH, graph);\r
-                    try {\r
-                        f.apply(Tuple0.INSTANCE);\r
-                    } finally {\r
-                        context.put(GRAPH, oldGraph);\r
-                        SCLContext.pop();\r
-                    }\r
-                }\r
-            });\r
-        }\r
-    }\r
-    \r
-    public static <T> T syncRead(final Function f) throws DatabaseException {\r
-        final SCLContext context = SCLContext.getCurrent();\r
-        Object graph = context.get(GRAPH);\r
-        if (graph != null) {\r
-            return (T)f.apply(Tuple0.INSTANCE);\r
-        } else {\r
-            return Simantics.getSession().syncRequest(new Read<T>() {\r
-                @Override\r
-                public T perform(ReadGraph graph) throws DatabaseException {\r
-                    SCLContext.push(context);\r
-                    ReadGraph oldGraph = (ReadGraph)context.put(GRAPH, graph);\r
-                    try {\r
-                        return (T)f.apply(Tuple0.INSTANCE);\r
-                    } finally {\r
-                        context.put(GRAPH, oldGraph);\r
-                        SCLContext.pop();\r
-                    }\r
-                }\r
-            });\r
-        }\r
-    }\r
-    \r
-    public static void asyncWrite(final Function f) throws DatabaseException {\r
-        final SCLContext context = SCLContext.getCurrent();\r
-        Object graph = context.get(GRAPH);\r
-        if (graph != null) {\r
-            f.apply(Tuple0.INSTANCE);\r
-        } else {\r
-            Simantics.getSession().asyncRequest(new WriteRequest() {\r
-                @Override\r
-                public void perform(WriteGraph graph) throws DatabaseException {\r
-                    SCLContext.push(context);\r
-                    ReadGraph oldGraph = (ReadGraph)context.put(GRAPH, graph);\r
-                    try {\r
-                        f.apply(Tuple0.INSTANCE);\r
-                    } finally {\r
-                        context.put(GRAPH, oldGraph);\r
-                        SCLContext.pop();\r
-                    }\r
-                }\r
-            });\r
-        }\r
-    }\r
-    \r
-    public static <T> T syncWrite(final Function f) throws DatabaseException {\r
-        final SCLContext context = SCLContext.getCurrent();\r
-        Object graph = context.get(GRAPH);\r
-        if (graph != null) {\r
-            return (T)f.apply(Tuple0.INSTANCE);\r
-        } else {\r
-            return Simantics.getSession().syncRequest(new WriteResultRequest<T>() {\r
-                @Override\r
-                public T perform(WriteGraph graph) throws DatabaseException {\r
-                    SCLContext.push(context);\r
-                    ReadGraph oldGraph = (ReadGraph)context.put(GRAPH, graph);\r
-                    try {\r
-                        return (T)f.apply(Tuple0.INSTANCE);\r
-                    } finally {\r
-                        context.put(GRAPH, oldGraph);\r
-                        SCLContext.pop();\r
-                    }\r
-                }\r
-            });\r
-        }\r
-    }\r
-    \r
-    public static <T> T delayedSyncWrite(final Function f) throws DatabaseException {\r
-        final SCLContext context = SCLContext.getCurrent();\r
-       final DataContainer<T> dc = new DataContainer<T>(null);\r
-\r
-        DelayedWriteRequest request = new DelayedWriteRequest() {\r
-            @Override\r
-            public void perform(WriteGraph graph) throws DatabaseException {\r
-               final SCLContext context = SCLContext.getCurrent();\r
-               SCLContext.push(context);\r
-                ReadGraph oldGraph = (ReadGraph)context.put(GRAPH, graph);\r
-                try {\r
-                    dc.set((T)f.apply(Tuple0.INSTANCE));\r
-                } finally {\r
-                    context.put(GRAPH, oldGraph);\r
-                    SCLContext.pop();\r
-                }\r
-            }\r
-        };\r
-       \r
-        Object graph = context.get(GRAPH);\r
-        if (graph != null) {\r
-            if (graph instanceof WriteGraph) {\r
-               ((WriteGraph)graph).syncRequest(request);\r
-            } else {\r
-               throw new DatabaseException("Caller is inside a read transaction.");\r
-            }\r
-        } else {\r
-            Simantics.getSession().syncRequest(request);\r
-        }\r
-       return dc.get();\r
-    }\r
-\r
-    public static <T> T virtualSyncWriteMem(WriteGraph graph, String virtualGraphId, final Function f) throws DatabaseException {\r
-        final SCLContext context = SCLContext.getCurrent();\r
-        VirtualGraphSupport vgs = graph.getService(VirtualGraphSupport.class);\r
-        VirtualGraph vg = vgs.getMemoryPersistent(virtualGraphId);\r
-        return graph.syncRequest(new WriteResultRequest<T>(vg) {\r
-            @Override\r
-            public T perform(WriteGraph graph) throws DatabaseException {\r
-                SCLContext.push(context);\r
-                ReadGraph oldGraph = (ReadGraph)context.put(GRAPH, graph);\r
-                try {\r
-                    return (T)f.apply(Tuple0.INSTANCE);\r
-                } finally {\r
-                    context.put(GRAPH, oldGraph);\r
-                    SCLContext.pop();\r
-                }\r
-            }\r
-        });\r
-    }\r
-    \r
-    public static <T> T virtualSyncWriteWS(WriteGraph graph, String virtualGraphId, final Function f) throws DatabaseException {\r
-        final SCLContext context = SCLContext.getCurrent();\r
-        VirtualGraphSupport vgs = graph.getService(VirtualGraphSupport.class);\r
-        VirtualGraph vg = vgs.getWorkspacePersistent(virtualGraphId);\r
-        return graph.syncRequest(new WriteResultRequest<T>(vg) {\r
-            @Override\r
-            public T perform(WriteGraph graph) throws DatabaseException {\r
-                SCLContext.push(context);\r
-                ReadGraph oldGraph = (ReadGraph)context.put(GRAPH, graph);\r
-                try {\r
-                    return (T)f.apply(Tuple0.INSTANCE);\r
-                } finally {\r
-                    context.put(GRAPH, oldGraph);\r
-                    SCLContext.pop();\r
-                }\r
-            }\r
-        });\r
-    }\r
-    \r
-    public static <T> T readValue(final String uri) throws DatabaseException {\r
-        return Simantics.getSession().syncRequest(new Read<T>() {\r
-            @Override\r
-            public T perform(ReadGraph graph) throws DatabaseException {\r
-                return Variables.getVariable(graph, uri).getValue(graph);\r
-            }            \r
-        });\r
-    }\r
-    \r
-    public static <T> void writeValue(final String uri, final T value) throws DatabaseException {\r
-        Simantics.getSession().syncRequest(new WriteRequest() {\r
-            @Override\r
-            public void perform(WriteGraph graph) throws DatabaseException {\r
-                Variables.getVariable(graph, uri).setValue(graph, value);\r
-            }            \r
-        });\r
-    }\r
-    \r
-    public static void activateOnce(Resource r) {\r
-        Simantics.getSession().getService(IActivationManager.class).activateOnce(r);\r
-    }\r
-    \r
-    public static void syncActivateOnce(WriteGraph graph, Resource r) throws DatabaseException {\r
-        graph.getService(IActivationManager.class).activateOnce(graph, r);\r
-    }\r
-\r
-    public static Resource resourceFromId(ReadGraph graph, long id) throws DatabaseException, IOException {\r
-        SerialisationSupport ss = graph.getService(SerialisationSupport.class);\r
-        return ss.getResource(id);\r
-    }\r
-    \r
-    public static void disableDependencies(WriteGraph graph) {\r
-        Layer0Utils.setDependenciesIndexingDisabled(graph, true);       \r
-    }\r
-    \r
-    public static void enableDependencies(WriteGraph graph) {\r
-        Layer0Utils.setDependenciesIndexingDisabled(graph, false);       \r
-    }\r
-    \r
-    public static void collectClusters() {\r
-        Simantics.getSession().getService(ClusterControl.class).collectClusters(Integer.MAX_VALUE);\r
-    }\r
-    \r
-    public static class SCLUnaryRead extends BinaryRead<Function1<Object,Object>, Object, Object> {\r
-\r
-               public SCLUnaryRead(Function1<Object, Object> parameter1, Object parameter2) {\r
-                       super(parameter1, parameter2);\r
-               }\r
-\r
-               @Override\r
-               public Object perform(ReadGraph graph) throws DatabaseException {\r
-                       return Simantics.applySCLRead(graph, parameter, parameter2);\r
-               }\r
-       \r
-    }\r
-    \r
-    public static Object unaryQuery(ReadGraph graph, Function1<Object,Object> fn, Object value) throws DatabaseException {\r
-       return graph.syncRequest(new SCLUnaryRead(fn, value));\r
-    }\r
-\r
-    public static Object unaryQueryCached(ReadGraph graph, Function1<Object,Object> fn, Object value) throws DatabaseException {\r
-       return graph.syncRequest(new SCLUnaryRead(fn, value), TransientCacheAsyncListener.<Object>instance());\r
-    }\r
-    \r
-}\r
+package org.simantics.scl.db;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.cojen.classfile.TypeDesc;
+import org.simantics.Simantics;
+import org.simantics.db.ReadGraph;
+import org.simantics.db.Resource;
+import org.simantics.db.VirtualGraph;
+import org.simantics.db.WriteGraph;
+import org.simantics.db.common.procedure.adapter.SyncListenerAdapter;
+import org.simantics.db.common.procedure.adapter.TransientCacheAsyncListener;
+import org.simantics.db.common.request.BinaryRead;
+import org.simantics.db.common.request.DelayedWriteRequest;
+import org.simantics.db.common.request.ReadRequest;
+import org.simantics.db.common.request.UnaryRead;
+import org.simantics.db.common.request.WriteRequest;
+import org.simantics.db.common.request.WriteResultRequest;
+import org.simantics.db.exception.DatabaseException;
+import org.simantics.db.layer0.util.Layer0Utils;
+import org.simantics.db.layer0.variable.Variables;
+import org.simantics.db.request.Read;
+import org.simantics.db.service.ClusterControl;
+import org.simantics.db.service.QueryControl;
+import org.simantics.db.service.SerialisationSupport;
+import org.simantics.db.service.VirtualGraphSupport;
+import org.simantics.layer0.utils.triggers.IActivationManager;
+import org.simantics.scl.compiler.elaboration.modules.SCLValue;
+import org.simantics.scl.compiler.environment.specification.EnvironmentSpecification;
+import org.simantics.scl.compiler.errors.DoesNotExist;
+import org.simantics.scl.compiler.errors.Failable;
+import org.simantics.scl.compiler.errors.Failure;
+import org.simantics.scl.compiler.internal.codegen.types.JavaTypeTranslator;
+import org.simantics.scl.compiler.module.Module;
+import org.simantics.scl.compiler.module.repository.ImportFailureException;
+import org.simantics.scl.compiler.runtime.RuntimeEnvironment;
+import org.simantics.scl.compiler.runtime.RuntimeModule;
+import org.simantics.scl.compiler.top.ValueNotFound;
+import org.simantics.scl.compiler.types.TCon;
+import org.simantics.scl.compiler.types.Type;
+import org.simantics.scl.compiler.types.Types;
+import org.simantics.scl.compiler.types.exceptions.MatchException;
+import org.simantics.scl.compiler.types.util.MultiFunction;
+import org.simantics.scl.osgi.SCLOsgi;
+import org.simantics.scl.reflection.ValueNotFoundException;
+import org.simantics.scl.runtime.SCLContext;
+import org.simantics.scl.runtime.function.Function;
+import org.simantics.scl.runtime.function.Function1;
+import org.simantics.scl.runtime.reporting.SCLReportingHandler;
+import org.simantics.scl.runtime.tuple.Tuple;
+import org.simantics.scl.runtime.tuple.Tuple0;
+import org.simantics.utils.DataContainer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+@SuppressWarnings({"rawtypes", "unchecked"})
+public class SCLFunctions {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(SCLFunctions.class);
+
+    public static final String GRAPH = "graph";
+
+    public static <T> T safeExec(final Function f) {
+        try {
+            return (T)f.apply(Tuple0.INSTANCE);
+        } catch (Throwable t) {
+            LOGGER.error("safeExec caught exception", t);
+            return null;
+        }
+    }
+
+    public static Function resolveFunction(RuntimeModule rm, String function) throws ValueNotFound {
+        return (Function)rm.getValue(function);
+    }
+    
+    private static SCLValue resolveSCLValue(RuntimeModule rm, String function) throws ValueNotFound {
+        return rm.getModule().getValue(function);
+    }
+    
+    private static RuntimeModule resolveRuntimeModule(String module) throws ValueNotFound {
+        Failable<RuntimeModule> f = SCLOsgi.MODULE_REPOSITORY.getRuntimeModule(module);
+        if(f.didSucceed())
+            return f.getResult();
+        else if(f == DoesNotExist.INSTANCE)
+            throw new ValueNotFound("Didn't find module " + module);
+        else
+            throw new ValueNotFound(((Failure)f).toString());
+    }
+    
+    private static List<TCon> getEffects(SCLValue value) throws ValueNotFoundException, ValueNotFound, MatchException {
+    
+        Type type = value.getType();
+        MultiFunction mfun = Types.matchFunction(type, 1);
+        ArrayList<TCon> concreteEffects = new ArrayList<>();
+        mfun.effect.collectConcreteEffects(concreteEffects);
+        return concreteEffects;
+        
+    }
+
+    public static List<TCon> getEffects(RuntimeModule rm, String function) throws ValueNotFoundException, ValueNotFound, MatchException {
+        return getEffects(resolveSCLValue(rm, function));
+    }
+
+    public static List<TCon> getEffects(String module, String function) throws ValueNotFoundException, ValueNotFound, MatchException {
+        return getEffects(resolveSCLValue(resolveRuntimeModule(module), function));
+    }
+    
+    private static <T> T evaluate(Function function, Object ... args) {
+        return (T)function.applyArray(args);
+    }
+
+    private static <T> T evaluate(RuntimeModule rm, String function, Object ... args) throws ValueNotFound {
+        return evaluate(resolveFunction(rm, function));
+    }
+
+    public static <T> T evaluate(String module, String function, Object ... args) throws ValueNotFound {
+        return evaluate(resolveRuntimeModule(module), function, args);
+    }
+
+    public static <T> T evaluateDB(String module, String function, Object ... args) throws DatabaseException {
+        try {
+            RuntimeModule rm = resolveRuntimeModule(module);
+            List<TCon> effects = getEffects(resolveSCLValue(rm, function));
+            Function f = resolveFunction(rm, function);
+            if(effects.contains(Types.WRITE_GRAPH)) {
+                return syncWrite(f, args);
+            } else if(effects.contains(Types.READ_GRAPH)) {
+                return syncRead(f, args);
+            } else {
+                return evaluate(f, args);
+            }
+        } catch (ValueNotFound e) {
+            throw new DatabaseException("SCL Value not found: " + e.name);
+        } catch (Throwable t) {
+            if (t instanceof DatabaseException)
+                throw (DatabaseException) t;
+            throw new DatabaseException(t);
+        }
+    }
+    
+    public static <T> T evaluateGraph(String module, String function, Object graph, Object ... args) throws DatabaseException {
+        final SCLContext context = SCLContext.getCurrent();
+        SCLContext.push(context);
+        Object oldGraph = context.put(GRAPH, graph);
+        try {
+            return evaluateDB(module, function, args);
+        } finally {
+            context.put(GRAPH, oldGraph);
+            SCLContext.pop();
+        }
+    }
+
+    private static Object[] NO_ARGS = new Object[] { Tuple0.INSTANCE };
+
+    public static <T> void asyncRead(final Function f) throws DatabaseException {    
+        asyncRead(f, NO_ARGS);
+    }
+
+    public static void asyncRead(final Function f, final Object ... args) throws DatabaseException {
+        final SCLContext context = SCLContext.createDerivedContext();
+        Simantics.getSession().asyncRequest(new ReadRequest() {
+            @Override
+            public void run(ReadGraph graph) throws DatabaseException {
+                SCLContext.push(context);
+                context.put(GRAPH, graph);
+                try {
+                    f.apply(Tuple0.INSTANCE);
+                } finally {
+                    SCLContext.pop();
+                }
+            }
+        });
+    }
+    
+    public static <T> T syncRead(final Function f) throws DatabaseException {
+        return syncRead(f, NO_ARGS);
+    }
+    
+    public static <T> T syncRead(final Function f, final Object ... args) throws DatabaseException {
+        final SCLContext context = SCLContext.getCurrent();
+        Object graph = context.get(GRAPH);
+        if (graph != null) {
+            return (T)f.applyArray(args);
+        } else {
+            return Simantics.getSession().syncRequest(new Read<T>() {
+                @Override
+                public T perform(ReadGraph graph) throws DatabaseException {
+                    SCLContext.push(context);
+                    ReadGraph oldGraph = (ReadGraph)context.put(GRAPH, graph);
+                    try {
+                        return (T)f.apply(Tuple0.INSTANCE);
+                    } finally {
+                        context.put(GRAPH, oldGraph);
+                        SCLContext.pop();
+                    }
+                }
+            });
+        }
+    }
+
+    public static void asyncWrite(final Function f) throws DatabaseException {
+        asyncWrite(f, NO_ARGS);
+    }
+
+    public static void asyncWrite(final Function f, final Object ... args) throws DatabaseException {
+        SCLContext context = SCLContext.createDerivedContext();
+        if (Simantics.peekSession() != null) {
+            Simantics.getSession().asyncRequest(new WriteRequest() {
+                @Override
+                public void perform(WriteGraph graph) throws DatabaseException {
+                    SCLContext.push(context);
+                    context.put(GRAPH, graph);
+                    try {
+                        f.apply(args);
+                    } finally {
+                        SCLContext.pop();
+                    }
+                }
+            });
+        } else {
+            LOGGER.warn("No session available for asynchronous write requests");
+        }
+    }
+    
+    public static <T> T syncWrite(final Function f) throws DatabaseException {
+        return syncWrite(f, NO_ARGS);
+    }
+
+    public static <T> T syncWrite(final Function f, final Object ... args) throws DatabaseException {
+        final SCLContext context = SCLContext.getCurrent();
+        Object graph = context.get(GRAPH);
+        if (graph != null) {
+            return (T)f.apply(Tuple0.INSTANCE);
+        } else {
+            final SCLReportingHandler printer = (SCLReportingHandler)SCLContext.getCurrent().get(SCLReportingHandler.REPORTING_HANDLER);
+            return Simantics.getSession().syncRequest(new WriteResultRequest<T>() {
+                @Override
+                public T perform(WriteGraph graph) throws DatabaseException {
+                    SCLContext.push(context);
+                    SCLReportingHandler oldPrinter = (SCLReportingHandler)context.put(SCLReportingHandler.REPORTING_HANDLER, printer);
+                    ReadGraph oldGraph = (ReadGraph)context.put(GRAPH, graph);
+                    try {
+                        return (T)f.apply(args);
+                    } finally {
+                        context.put(GRAPH, oldGraph);
+                        context.put(SCLReportingHandler.REPORTING_HANDLER, oldPrinter);
+                        SCLContext.pop();
+                    }
+                }
+            });
+        }
+    }
+    
+    public static <T> T delayedSyncWrite(final Function f) throws DatabaseException {
+        final SCLContext context = SCLContext.getCurrent();
+        final DataContainer<T> dc = new DataContainer<T>(null);
+
+        DelayedWriteRequest request = new DelayedWriteRequest() {
+            @Override
+            public void perform(WriteGraph graph) throws DatabaseException {
+                final SCLContext context = SCLContext.getCurrent();
+                SCLContext.push(context);
+                ReadGraph oldGraph = (ReadGraph)context.put(GRAPH, graph);
+                try {
+                    dc.set((T)f.apply(Tuple0.INSTANCE));
+                } finally {
+                    context.put(GRAPH, oldGraph);
+                    SCLContext.pop();
+                }
+            }
+        };
+    
+        Object graph = context.get(GRAPH);
+        if (graph != null) {
+            if (graph instanceof WriteGraph) {
+                ((WriteGraph)graph).syncRequest(request);
+            } else {
+                throw new DatabaseException("Caller is inside a read transaction.");
+            }
+        } else {
+            Simantics.getSession().syncRequest(request);
+        }
+        return dc.get();
+    }
+
+    public static <T> T virtualSyncWriteMem(WriteGraph graph, String virtualGraphId, final Function f) throws DatabaseException {
+        final SCLContext context = SCLContext.getCurrent();
+        VirtualGraphSupport vgs = graph.getService(VirtualGraphSupport.class);
+        VirtualGraph vg = vgs.getMemoryPersistent(virtualGraphId);
+        return graph.syncRequest(new WriteResultRequest<T>(vg) {
+            @Override
+            public T perform(WriteGraph graph) throws DatabaseException {
+                SCLContext.push(context);
+                ReadGraph oldGraph = (ReadGraph)context.put(GRAPH, graph);
+                try {
+                    return (T)f.apply(Tuple0.INSTANCE);
+                } finally {
+                    context.put(GRAPH, oldGraph);
+                    SCLContext.pop();
+                }
+            }
+        });
+    }
+    
+    public static <T> T virtualSyncWriteWS(WriteGraph graph, String virtualGraphId, final Function f) throws DatabaseException {
+        final SCLContext context = SCLContext.getCurrent();
+        VirtualGraphSupport vgs = graph.getService(VirtualGraphSupport.class);
+        VirtualGraph vg = vgs.getWorkspacePersistent(virtualGraphId);
+        return graph.syncRequest(new WriteResultRequest<T>(vg) {
+            @Override
+            public T perform(WriteGraph graph) throws DatabaseException {
+                SCLContext.push(context);
+                ReadGraph oldGraph = (ReadGraph)context.put(GRAPH, graph);
+                try {
+                    return (T)f.apply(Tuple0.INSTANCE);
+                } finally {
+                    context.put(GRAPH, oldGraph);
+                    SCLContext.pop();
+                }
+            }
+        });
+    }
+    
+    public static <T> T readValue(final String uri) throws DatabaseException {
+        return Simantics.getSession().syncRequest(new Read<T>() {
+            @Override
+            public T perform(ReadGraph graph) throws DatabaseException {
+                return Variables.getVariable(graph, uri).getValue(graph);
+            }
+        });
+    }
+    
+    public static <T> void writeValue(final String uri, final T value) throws DatabaseException {
+        Simantics.getSession().syncRequest(new WriteRequest() {
+            @Override
+            public void perform(WriteGraph graph) throws DatabaseException {
+                Variables.getVariable(graph, uri).setValue(graph, value);
+            }
+        });
+    }
+    
+    public static void activateOnce(Resource r) {
+        Simantics.getSession().getService(IActivationManager.class).activateOnce(r);
+    }
+    
+    public static void syncActivateOnce(WriteGraph graph, Resource r) throws DatabaseException {
+        graph.getService(IActivationManager.class).activateOnce(graph, r);
+    }
+
+    public static Resource resourceFromId(ReadGraph graph, long id) throws DatabaseException, IOException {
+        SerialisationSupport ss = graph.getService(SerialisationSupport.class);
+        return ss.getResource(id);
+    }
+    
+    public static void disableDependencies(WriteGraph graph) {
+        Layer0Utils.setDependenciesIndexingDisabled(graph, true);       
+    }
+    
+    public static void enableDependencies(WriteGraph graph) {
+        Layer0Utils.setDependenciesIndexingDisabled(graph, false);       
+    }
+    
+    public static void collectClusters() {
+        Simantics.getSession().getService(ClusterControl.class).collectClusters(Integer.MAX_VALUE);
+    }
+    
+    public static class SCLUnaryRead extends BinaryRead<Function1<Object,Object>, Object, Object> {
+
+        public SCLUnaryRead(Function1<Object, Object> parameter1, Object parameter2) {
+             super(parameter1, parameter2);
+        }
+
+        @Override
+        public Object perform(ReadGraph graph) throws DatabaseException {
+            return Simantics.applySCLRead(graph, parameter, parameter2);
+        }
+
+    }
+    
+    public static Object unaryQuery(ReadGraph graph, Function1<Object,Object> fn, Object value) throws DatabaseException {
+        return graph.syncRequest(new SCLUnaryRead(fn, value));
+    }
+
+    public static Object unaryQueryCached(ReadGraph graph, Function1<Object,Object> fn, Object value) throws DatabaseException {
+        return graph.syncRequest(new SCLUnaryRead(fn, value), TransientCacheAsyncListener.<Object>instance());
+    }
+    
+
+    private static class Subquery extends UnaryRead<Function, Object> {
+
+        public Subquery(Function q) {
+            super(q);
+        }
+
+        @Override
+        public Object perform(ReadGraph graph) throws DatabaseException {
+            return Simantics.applySCLRead(graph, parameter, Tuple0.INSTANCE);
+        }
+
+    }
+
+    public static Object subquery(ReadGraph graph, Function q) throws DatabaseException {
+        return graph.syncRequest(new Subquery(q));
+    }
+
+    public static Object subqueryC(ReadGraph graph, Function q) throws DatabaseException {
+        return graph.syncRequest(new Subquery(q), TransientCacheAsyncListener.<Object>instance());
+    }
+    
+    public static void subqueryL(ReadGraph graph, Function query, Function executeCallback, Function1<Throwable, Tuple> exceptionCallback, Function1<Tuple0, Boolean> isDisposedCallback) throws DatabaseException {
+        graph.syncRequest(new Subquery(query), new SyncListenerAdapter<Object>() {
+            @Override
+            public void execute(ReadGraph graph, Object result) throws DatabaseException {
+                Simantics.applySCLRead(graph, executeCallback, result);
+            }
+            
+            @Override
+            public void exception(ReadGraph graph, Throwable t) throws DatabaseException {
+                Simantics.applySCLRead(graph, exceptionCallback, t);
+            }
+            
+            @Override
+            public boolean isDisposed() {
+                return isDisposedCallback.apply(Tuple0.INSTANCE);
+            }
+        });
+    }
+
+    public static Object possibleFromDynamic(Type expectedType, String moduleName, Object value) {
+    
+        try {
+
+        
+            Failable<Module> failable = SCLOsgi.MODULE_REPOSITORY.getModule(moduleName);
+            Module module = failable.getResult();
+            
+            RuntimeEnvironment env = SCLOsgi.MODULE_REPOSITORY.createRuntimeEnvironment(
+            EnvironmentSpecification.of(moduleName, ""), module.getParentClassLoader());
+
+            JavaTypeTranslator tr = new JavaTypeTranslator(env.getEnvironment());
+            TypeDesc desc = tr.toTypeDesc(expectedType);
+            String className = desc.getFullName();
+            Class<?> clazz = env.getMutableClassLoader().loadClass(className);
+            if (!clazz.isAssignableFrom(value.getClass()))
+                return null;
+            
+        } catch (ImportFailureException | ClassNotFoundException e) {
+        }
+        return value;
+    }
+
+    public static void restrictQueries(ReadGraph graph, int amount, int step, int maxTimeInMs) {
+
+        QueryControl qc = graph.getService(QueryControl.class);
+        long start = System.currentTimeMillis();
+        while(true) {
+            int current = qc.count();
+            if(current < amount) return;
+            qc.gc(graph, step);
+            long duration = System.currentTimeMillis() - start;
+            if(duration > maxTimeInMs) return;
+        }
+
+    }
+
+    public static int countQueries(ReadGraph graph) {
+
+        QueryControl qc = graph.getService(QueryControl.class);
+        return qc.count();
+
+    }
+    
+}