Issue #3235 a formula to extract and format timestamp from pv values

Author: shroffk

core/formula/doc/index.rst

@@ -164,6 +164,12 @@ Enum
 
 **indexOf(Enum e)** - Return the index of the enum value.
 
+Time
+----
+
+**timestamp(VType value)** - returns the timestamp of the provided value formatted using the millisecond format.
+
+**timestamp(VType value, String format)** - returns the timestamp of the provided value formatted using the user defined format.
 
 Alarm
 -----

core/formula/pom.xml

@@ -17,6 +17,11 @@
       <groupId>org.phoebus</groupId>
       <artifactId>core-vtype</artifactId>
       <version>4.7.4-SNAPSHOT</version>
+    </dependency>
+    <dependency>
+      <groupId>org.phoebus</groupId>
+      <artifactId>core-util</artifactId>
+      <version>4.7.4-SNAPSHOT</version>
     </dependency>
       <dependency>
           <groupId>org.junit.jupiter</groupId>
@@ -30,5 +35,11 @@
       <version>1.3</version>
       <scope>test</scope>
     </dependency>
+      <dependency>
+          <groupId>org.phoebus</groupId>
+          <artifactId>core-util</artifactId>
+          <version>4.7.4-SNAPSHOT</version>
+          <scope>compile</scope>
+      </dependency>
   </dependencies>
 </project>

core/formula/src/main/java/org/csstudio/apputil/formula/time/TimestampFunction.java

@@ -0,0 +1,68 @@
+package org.csstudio.apputil.formula.time;
+
+import org.csstudio.apputil.formula.array.BaseArrayFunction;
+import org.csstudio.apputil.formula.spi.FormulaFunction;
+import org.epics.vtype.Alarm;
+import org.epics.vtype.Time;
+import org.epics.vtype.VString;
+import org.epics.vtype.VType;
+import org.phoebus.core.vtypes.VTypeHelper;
+
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import static org.phoebus.util.time.TimestampFormats.MILLI_FORMAT;
+
+/**
+ * Extract the timestamps from PV values
+ */
+public class TimestampFunction implements FormulaFunction {
+
+    final private static ZoneId zone = ZoneId.systemDefault();
+    final private static VString emptyString = VString.of("", Alarm.none(), Time.now());
+
+    @Override
+    public String getCategory() {
+        return "time";
+    }
+
+    @Override
+    public String getName() {
+        return "timestamp";
+    }
+
+    @Override
+    public String getDescription() {
+        return "Returns the timestamp of the last update";
+    }
+
+    @Override
+    public List<String> getArguments() {
+        return List.of("pv_name", "time format (optional)");
+    }
+
+    @Override
+    public boolean isVarArgs() {
+        return true;
+    }
+
+    private Map<String, DateTimeFormatter> formatters = new HashMap<>();
+
+    @Override
+    public VType compute(VType... args) {
+        if (args.length == 1) {
+            return VString.of(MILLI_FORMAT.format(VTypeHelper.getTimestamp(args[0])), Alarm.none(), Time.now());
+        } else if (args.length == 2) {
+            String format = VTypeHelper.toString(args[1]);
+            if (!formatters.containsKey(format)) {
+                formatters.put(format, DateTimeFormatter.ofPattern(VTypeHelper.toString(args[1])).withZone(zone));
+            }
+            return VString.of(formatters.get(format).format(VTypeHelper.getTimestamp(args[0])), Alarm.none(), Time.now());
+        }
+        return emptyString;
+
+    }
+}

core/formula/src/main/resources/META-INF/services/org.csstudio.apputil.formula.spi.FormulaFunction

@@ -74,3 +74,5 @@ org.csstudio.apputil.formula.alarm.MinorAlarmFunction
 org.csstudio.apputil.formula.enums.IndexOfFunction
 org.csstudio.apputil.formula.enums.EnumOfFunction
 
+# Time
+org.csstudio.apputil.formula.time.TimestampFunction