#295 Proposal for extension of function fromMillis

src/main/java/com/api/jsonata4java/expressions/functions/FromMillisZonedFunction.java

@@ -0,0 +1,126 @@
+/**
+ * (c) Copyright 2018, 2019 IBM Corporation
+ * 1 New Orchard Road, 
+ * Armonk, New York, 10504-1722
+ * United States
+ * +1 914 499 1900
+ * support: Nathaniel Mills [email protected]
+ *
+ * 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 com.api.jsonata4java.expressions.functions;
+
+import com.api.jsonata4java.expressions.EvaluateRuntimeException;
+import com.api.jsonata4java.expressions.ExpressionsVisitor;
+import com.api.jsonata4java.expressions.generated.MappingExpressionParser.Function_callContext;
+import com.api.jsonata4java.expressions.utils.Constants;
+import com.api.jsonata4java.expressions.utils.DateTimeUtils;
+import com.api.jsonata4java.expressions.utils.FunctionUtils;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.JsonNodeFactory;
+import com.fasterxml.jackson.databind.node.TextNode;
+
+/**
+ * From http://docs.jsonata.org/string-functions.html:
+ * 
+ * $fromMillis(number)
+ * 
+ * Convert a number representing milliseconds since the Unix Epoch (1 January,
+ * 1970 UTC) to a timestamp string in the ISO 8601 format.
+ * 
+ * Examples
+ * 
+ * $fromMillis(1510067557121)=="2017-11-07T15:12:37.121Z"
+ * 
+ */
+public class FromMillisZonedFunction extends FunctionBase {
+
+    public static String ERR_BAD_CONTEXT = String.format(Constants.ERR_MSG_BAD_CONTEXT, Constants.FUNCTION_FROM_MILLIS);
+    public static String ERR_ARG1BADTYPE = String.format(Constants.ERR_MSG_ARG1_BAD_TYPE,
+        Constants.FUNCTION_FROM_MILLIS);
+    public static String ERR_ARG2BADTYPE = String.format(Constants.ERR_MSG_ARG2_BAD_TYPE,
+        Constants.FUNCTION_FROM_MILLIS);
+
+    public JsonNode invoke(ExpressionsVisitor expressionVisitor, Function_callContext ctx) {
+        // Create the variable to return
+        JsonNode result = null;
+
+        // Retrieve the number of arguments
+        JsonNode argNumber = JsonNodeFactory.instance.nullNode();
+        boolean useContext = FunctionUtils.useContextVariable(this, ctx, getSignature());
+        int argCount = getArgumentCount(ctx);
+        if (useContext) {
+            argNumber = FunctionUtils.getContextVariable(expressionVisitor);
+            if (argNumber != null && argNumber.isNull() == false) {
+                argCount++;
+            } else {
+                useContext = false;
+            }
+        }
+
+        // Make sure that we have the right number of arguments
+        if (argCount >= 1 && argCount <= 3) {
+            if (!useContext) {
+                argNumber = FunctionUtils.getValuesListExpression(expressionVisitor, ctx, 0);
+            }
+            JsonNode picture = JsonNodeFactory.instance.nullNode();
+            if (argCount >= 2) {
+                picture = FunctionUtils.getValuesListExpression(expressionVisitor, ctx, useContext ? 0 : 1);
+            }
+            JsonNode timezone = JsonNodeFactory.instance.nullNode();
+            if (argCount == 3) {
+                timezone = FunctionUtils.getValuesListExpression(expressionVisitor, ctx, useContext ? 1 : 2);
+            }
+            if (argNumber == null) {
+                return null;
+            }
+            if (argNumber.isNumber()) {
+                final Long millis = argNumber.asLong();
+                String pictureStr = null;
+                if (picture != null && picture.isNull() == false) {
+                    pictureStr = picture.asText();
+                }
+                String timezoneStr = null;
+                if (timezone != null && timezone.isNull() == false) {
+                    timezoneStr = timezone.asText();
+                }
+                result = new TextNode(DateTimeUtils.formatDateTimeFromZoneId(millis, pictureStr, timezoneStr));
+            } else {
+                throw new EvaluateRuntimeException(ERR_ARG1BADTYPE);
+            }
+        } else {
+            throw new EvaluateRuntimeException(ERR_BAD_CONTEXT);
+        }
+
+        return result;
+    }
+
+    @Override
+    public int getMaxArgs() {
+        return 3;
+    }
+
+    @Override
+    public int getMinArgs() {
+        return 0; // account for context variable
+    }
+
+    @Override
+    public String getSignature() {
+        // accepts a number (or context variable), an optional string, another optional
+        // string, returns a number
+        return "<n-s?s?:s>";
+    }
+}

src/main/java/com/api/jsonata4java/expressions/utils/Constants.java

@@ -46,6 +46,7 @@
 import com.api.jsonata4java.expressions.functions.FormatBaseFunction;
 import com.api.jsonata4java.expressions.functions.FormatNumberFunction;
 import com.api.jsonata4java.expressions.functions.FromMillisFunction;
+import com.api.jsonata4java.expressions.functions.FromMillisZonedFunction;
 import com.api.jsonata4java.expressions.functions.FunctionBase;
 import com.api.jsonata4java.expressions.functions.JoinFunction;
 import com.api.jsonata4java.expressions.functions.KeysFunction;
@@ -111,6 +112,7 @@ public class Constants implements Serializable {
     public static final String FUNCTION_REPLACE = "$replace";
     public static final String FUNCTION_NOW = "$now";
     public static final String FUNCTION_FROM_MILLIS = "$fromMillis";
+    public static final String FUNCTION_FROM_MILLIS_ZONED = "$fromMillisZoned";
     public static final String FUNCTION_FORMAT_NUMBER = "$formatNumber";
     public static final String FUNCTION_FORMAT_BASE = "$formatBase";
     public static final String FUNCTION_BASE64_ENCODE = "$base64encode";
@@ -193,6 +195,7 @@ public class Constants implements Serializable {
         FUNCTIONS.put(FUNCTION_REPLACE, new ReplaceFunction());
         FUNCTIONS.put(FUNCTION_NOW, new NowFunction());
         FUNCTIONS.put(FUNCTION_FROM_MILLIS, new FromMillisFunction());
+        FUNCTIONS.put(FUNCTION_FROM_MILLIS_ZONED, new FromMillisZonedFunction());
         FUNCTIONS.put(FUNCTION_FORMAT_NUMBER, new FormatNumberFunction());
         FUNCTIONS.put(FUNCTION_FORMAT_BASE, new FormatBaseFunction());
         FUNCTIONS.put(FUNCTION_BASE64_ENCODE, new Base64EncodeFunction());