InvalidParameterEvent and listener support implementation. (apache#21)

* InvalidParameterEvent and listener support implementation.

* Bad copy-paste, fix.

* Using parameter annotation to determine the (FEEL spec) param name.

* Refining error message by using FEELEvent as Either/Left.

* InvalidParameterEvent avoid hard-coded msg in favor of i18n-friendly dynamic structure.

* Extending InvalidParametersEvent support.

* Extending InvalidParametersEvent support.

* Extending InvalidParametersEvent support.

* Extending InvalidParametersEvent support.

* For BaseFEELFunction pairing slf4j log with FEELEvent based notification.

* Minor corrections and minor refactorings.

* Extending InvalidParametersEvent support to CustomFEELFunction.

* Fixing BaseFEELFunction support for Either, minor refactorings.

* Extending FEELEvent support to Java(FEEL)Function.

* Extending FEELEvent support to DTInvokerFunction, small DMN-level fix.

* .

* Normalize BigDecimal creation for functions via EvalHelper.getBigDecimalOrNull .

* Refactoring by implementing FEELFnResult<T> as an "alias" for Either<FEELEvent, T> .

* Include license header to items which missed it

Author: tarilabs

kie-dmn-core/src/main/java/org/kie/dmn/core/ast/DecisionNode.java

@@ -31,6 +31,7 @@
 import org.kie.dmn.feel.runtime.events.FEELEventListener;
 
 import java.util.*;
+import java.util.function.Function;
 
 public class DecisionNode extends DMNBaseNode implements DMNNode {
 
@@ -147,7 +148,7 @@ public EvaluatorResult evaluate(InternalDMNRuntimeEventManager eventManager, DMN
                     params[i] = feel.evaluate( paramNames.get( i ), result.getContext().getAll() );
                     ctx.setValue( paramNames.get( i ), params[i] );
                 }
-                Object dtr = dt.apply( ctx, params );
+                Object dtr = dt.apply( ctx, params ).cata(e -> { events.add(e); return null; }, Function.identity());
                 r = processEvents( events, eventManager, result );
                 return new EvaluatorResult( dtr, r.hasErrors ? ResultType.FAILURE : ResultType.SUCCESS );
             } finally {

kie-dmn-core/src/main/java/org/kie/dmn/core/impl/FeelTypeImpl.java

@@ -83,11 +83,13 @@ public void setAllowedValues(List<?> allowedValues) {
 
     @Override
     public Object parseValue(String value) {
+        // TODO we should add the EventListener here somehow?
         return feelType.fromString( value );
     }
 
     @Override
     public String toString(Object value) {
+        // TODO we should add the EventListener here somehow?
         return feelType.toString( value );
     }
 

kie-dmn-feel/src/main/java/org/kie/dmn/feel/lang/FEELProperty.java

@@ -1,3 +1,19 @@
+/*
+ * Copyright 2016 Red Hat, Inc. and/or its affiliates.
+ *
+ * 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.
+ */
+
 package org.kie.dmn.feel.lang;
 
 import static java.lang.annotation.RetentionPolicy.RUNTIME;

kie-dmn-feel/src/main/java/org/kie/dmn/feel/lang/FEELType.java

@@ -1,3 +1,19 @@
+/*
+ * Copyright 2016 Red Hat, Inc. and/or its affiliates.
+ *
+ * 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.
+ */
+
 package org.kie.dmn.feel.lang;
 
 import static java.lang.annotation.ElementType.TYPE;
@@ -6,7 +22,6 @@
 import java.lang.annotation.Retention;
 import java.lang.annotation.Target;
 
-
 @Retention(RUNTIME)
 @Target(TYPE)
 public @interface FEELType {

kie-dmn-feel/src/main/java/org/kie/dmn/feel/lang/Type.java

@@ -20,8 +20,10 @@ public interface Type {
 
     String getName();
 
+    // TODO possibly to separate in a marshaller
     Object fromString( String value );
 
+    // TODO possibly to separate in a marshaller
     String toString( Object value );
 
 }

kie-dmn-feel/src/main/java/org/kie/dmn/feel/lang/types/BuiltInType.java

@@ -22,12 +22,14 @@
 import org.kie.dmn.feel.runtime.FEELFunction;
 import org.kie.dmn.feel.runtime.Range;
 import org.kie.dmn.feel.runtime.UnaryTest;
+import org.kie.dmn.feel.runtime.events.FEELEvent;
 import org.kie.dmn.feel.runtime.functions.*;
 
 import java.math.BigDecimal;
 import java.time.*;
 import java.util.List;
 import java.util.Map;
+import java.util.function.Function;
 
 public enum BuiltInType implements Type {
 
@@ -60,12 +62,12 @@ public String getName() {
     @Override
     public Object fromString(String value) {
         switch ( this ) {
-            case NUMBER: return BuiltInFunctions.getFunction( NumberFunction.class).apply( value, null, null );
+            case NUMBER: return BuiltInFunctions.getFunction( NumberFunction.class).apply( value, null, null ).cata(BuiltInType.justNull(), Function.identity());
             case STRING: return value;
-            case DATE: return BuiltInFunctions.getFunction( DateFunction.class ).apply( value );
-            case TIME: return BuiltInFunctions.getFunction( TimeFunction.class ).apply( value );
-            case DATE_TIME: return BuiltInFunctions.getFunction( DateTimeFunction.class ).apply( value );
-            case DURATION: return BuiltInFunctions.getFunction( DurationFunction.class ).apply( value );
+            case DATE: return BuiltInFunctions.getFunction( DateFunction.class ).apply( value ).cata(BuiltInType.justNull(), Function.identity());
+            case TIME: return BuiltInFunctions.getFunction( TimeFunction.class ).apply( value ).cata(BuiltInType.justNull(), Function.identity());
+            case DATE_TIME: return BuiltInFunctions.getFunction( DateTimeFunction.class ).apply( value ).cata(BuiltInType.justNull(), Function.identity());
+            case DURATION: return BuiltInFunctions.getFunction( DurationFunction.class ).apply( value ).cata(BuiltInType.justNull(), Function.identity());
             case BOOLEAN: return Boolean.parseBoolean( value );
             case RANGE:
             case FUNCTION:
@@ -79,7 +81,12 @@ public Object fromString(String value) {
 
     @Override
     public String toString(Object value) {
-        return BuiltInFunctions.getFunction( StringFunction.class ).apply( value );
+        return BuiltInFunctions.getFunction( StringFunction.class ).apply( value ).cata(BuiltInType.justNull(), Function.identity());
+    }
+    
+    static <T> Function<FEELEvent, T> justNull() {
+        // TODO we should add the EventListener here somehow?
+        return t -> null;
     }
 
     public Symbol getSymbol() { return symbol; }

kie-dmn-feel/src/main/java/org/kie/dmn/feel/runtime/decisiontables/DecisionTableImpl.java

@@ -88,7 +88,7 @@ public Object evaluate(EvaluationContext ctx, Object[] params) {
                 return null;
             }
         } catch ( Exception e ) {
-            logger.error( "Error invoking decision table '" + getName() + "'.", e );
+            // no longer needed as DTInvokerFunction support Either for wrapping the exception : logger.error( "Error invoking decision table '" + getName() + "'.", e );
             throw e;
         }
     }

kie-dmn-feel/src/main/java/org/kie/dmn/feel/runtime/events/InvalidParametersEvent.java

@@ -0,0 +1,121 @@
+/*
+ * Copyright 2016 Red Hat, Inc. and/or its affiliates.
+ *
+ * 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.
+ */
+
+package org.kie.dmn.feel.runtime.events;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+/**
+ * An event class to report an evaluation error occured due to invalid parameters.
+ */
+public class InvalidParametersEvent
+        extends FEELEventBase
+        implements FEELEvent {
+
+    private String genericProblem;
+    private String paramNameInError;
+    private String paramProblem;
+    private String nodeName;
+    private final Map<String, Object> actualParameters = new HashMap<>();
+    
+    public InvalidParametersEvent(Severity severity, String genericProblem) {
+        super( severity, null, null );
+        this.genericProblem = genericProblem;
+    }
+    
+    public InvalidParametersEvent(Severity severity, String genericProblem, Throwable sourceException ) {
+        super( severity, null, sourceException );
+        this.genericProblem = genericProblem;
+    }
+    
+    public InvalidParametersEvent(Severity severity, String paramNameInError, String paramProblem) {
+        super( severity, null, null );
+        this.paramNameInError = paramNameInError;
+        this.paramProblem = paramProblem;
+    }
+    
+    public InvalidParametersEvent(Severity severity, String paramNameInError, String paramProblem, Throwable sourceException ) {
+        super( severity, null, sourceException );
+        this.paramNameInError = paramNameInError;
+        this.paramProblem = paramProblem;
+    }
+    
+    @Override
+    public String getMessage() {
+        if (genericProblem == null ) {
+            return "The parameter '"+paramNameInError+"', in function "+getNodeName()+"(), "+paramProblem+".";
+        } else {
+            return genericProblem;
+        }
+    }
+    
+    public void setNodeName(String nodeName) {
+        this.nodeName = nodeName;
+    }
+
+    public String getNodeName() {
+        return nodeName;
+    }
+    
+    public void setActualParameters(List<String> parameterNames, List<Object> parameterValues) {
+        this.actualParameters.clear();
+        IntStream.range(0, parameterNames.size())
+            .forEach( idx -> actualParameters.put(parameterNames.get(idx), parameterValues.get(idx)) );
+    }
+
+    public Map<String, Object> getActualParameters() {
+        return Collections.unmodifiableMap( actualParameters );
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder builder = new StringBuilder();
+        builder.append("InvalidParametersEvent{")
+            .append("getSeverity()=").append(getSeverity())
+            .append(", nodeName=").append(nodeName)
+            .append(", message=").append(getMessage())
+            .append(", actualParameters=").append(formatMap(actualParameters))
+            .append(", paramNameInError=").append(paramNameInError)
+            .append(", paramProblem=").append(paramProblem)
+            .append(", getSourceException()=").append(getSourceException())
+            .append("}");
+        return builder.toString();
+    }
+
+    private String formatMap(Map<String, Object> actualParameters) {
+        try {
+            StringBuilder sb = new StringBuilder("{");
+            sb.append(
+                actualParameters.entrySet().stream()
+                    .map(kv -> kv.getKey() + "=" + ( kv.getValue() != null && kv.getValue().getClass().isArray() ? Arrays.deepToString( (Object[]) kv.getValue() ) : kv.getValue() ) )
+                    .collect(Collectors.joining(", "))
+            );
+            sb.append("}");
+            return sb.toString();
+        } catch (Exception e) {
+            e.printStackTrace();
+            return "<unable to inspect actualParameters map>";
+        }
+    }
+}

kie-dmn-feel/src/main/java/org/kie/dmn/feel/runtime/functions/AppendFunction.java

@@ -20,20 +20,30 @@
 import java.util.List;
 import java.util.stream.Stream;
 
+import org.kie.dmn.feel.lang.impl.FEELEventListenersManager;
+import org.kie.dmn.feel.runtime.events.InvalidInputEvent;
+import org.kie.dmn.feel.runtime.events.InvalidParametersEvent;
+import org.kie.dmn.feel.runtime.functions.FEELFnResult;
+import org.kie.dmn.feel.runtime.events.FEELEvent;
+import org.kie.dmn.feel.runtime.events.FEELEvent.Severity;
+
 public class AppendFunction
         extends BaseFEELFunction {
 
     public AppendFunction() {
         super( "append" );
     }
 
-    public List apply( @ParameterName( "list" ) List list, @ParameterName( "item" ) Object[] items ) {
-        if ( list == null || items == null ) {
-            return null;
+    public FEELFnResult<List> apply( @ParameterName( "list" ) List list, @ParameterName( "item" ) Object[] items ) {
+        if ( list == null ) {
+            return FEELFnResult.ofError(new InvalidParametersEvent(Severity.ERROR, "list", "cannot be null"));
+        }
+        if ( items == null ) {
+            return FEELFnResult.ofError(new InvalidParametersEvent(Severity.ERROR, "item", "cannot be null"));
         }
         // spec requires us to return a new list
         List result = new ArrayList( list );
         Stream.of( items ).forEach( i -> result.add( i ) );
-        return result;
+        return FEELFnResult.ofResult( result );
     }
 }