Merge pull request #7 from jembishop/get-data-multiple-pvs

Add support for fetching multiple PVs from archiver

lib/src/main/java/org/epics/archiverappliance/retrieval/client/DataRetrieval.java

@@ -8,21 +8,25 @@
 package org.epics.archiverappliance.retrieval.client;
 
 import java.sql.Timestamp;
+import java.util.Collections;
+import java.util.List;
 import java.util.Map;
 
 /**
  * Main interface for client retrieving data using the PB/HTTP protocol.
  * @author mshankar
  */
-public interface DataRetrieval {
+public abstract class DataRetrieval {
     /**
      * Get data for PV pvName from starttime to endtime. By default, we expect to get raw data.
      * @param pvName The name of the pv
      * @param startTime Start time of request
      * @param endTime End time of request
      * @return Return an iterator over the data.
      */
-    public GenMsgIterator getDataForPV(String pvName, Timestamp startTime, Timestamp endTime);
+    public final GenMsgIterator getDataForPV(String pvName, Timestamp startTime, Timestamp endTime) {
+        return getDataForPV(pvName, startTime, endTime, false);
+    };
     /**
      * Get data for PV pvName from starttime to endtime using the system defined sparsification operator.
      * @param pvName The name of the pv
@@ -31,8 +35,10 @@ public interface DataRetrieval {
      * @param useReducedDataSet - If true, use the server defined sparsification operator...
      * @return Return an iterator over the data.
      */
-    public GenMsgIterator getDataForPV(
-            String pvName, Timestamp startTime, Timestamp endTime, boolean useReducedDataSet);
+    public final GenMsgIterator getDataForPV(
+            String pvName, Timestamp startTime, Timestamp endTime, boolean useReducedDataSet) {
+                return getDataForPV(pvName, startTime, endTime, useReducedDataSet, null);
+            }
 
     /**
      * Get data for PV pvName from starttime to endtime using the system defined sparsification operator; pass additional params in the HTTP call.
@@ -43,10 +49,30 @@ public GenMsgIterator getDataForPV(
      * @param otherParams - Any other name/value pairs that are passed onto the server.
      * @return Return an iterator over the data.
      */
-    public GenMsgIterator getDataForPV(
+    public final GenMsgIterator getDataForPV(
             String pvName,
             Timestamp startTime,
             Timestamp endTime,
             boolean useReducedDataSet,
+            Map<String, String> otherParams) {
+                return getDataForPVs(Collections.singletonList(pvName), startTime, endTime, useReducedDataSet, otherParams);
+            }
+
+    /**
+     * Get data for PVs in pvNames from starttime to endtime using the system defined sparsification operator; pass additional params in the HTTP call.
+     * NOTE: The data for all the PVs will be concatenated together. To identify which PV is currently being read, you must register your own 
+     * {@code InfoChangeHandler} to the returned {@code GenMsgIterator} using {@code onInfoChange}.
+     * @param pvName The name of the pv
+     * @param startTime Start time of request
+     * @param endTime End time of request
+     * @param useReducedDataSet - If true, use the server defined sparsification operator...
+     * @param otherParams - Any other name/value pairs that are passed onto the server.
+     * @return Return an iterator over the data.
+     */
+    public abstract GenMsgIterator getDataForPVs(
+            List<String> pvNames,
+            Timestamp startTime,
+            Timestamp endTime,
+            boolean useReducedDataSet,
             Map<String, String> otherParams);
 }

lib/src/main/java/org/epics/archiverappliance/retrieval/client/RawDataRetrieval.java

@@ -13,6 +13,7 @@
 import java.net.URLEncoder;
 import java.nio.charset.StandardCharsets;
 import java.sql.Timestamp;
+import java.util.List;
 import java.util.Map;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -23,7 +24,7 @@
  *
  * @author mshankar
  */
-public class RawDataRetrieval implements DataRetrieval {
+public class RawDataRetrieval extends DataRetrieval {
     private static final Logger logger = Logger.getLogger(RawDataRetrieval.class.getName());
     private final String accessURL;
 
@@ -36,31 +37,24 @@ private static String convertToUTC(Timestamp time) {
     }
 
     @Override
-    public GenMsgIterator getDataForPV(String pvName, Timestamp startTime, Timestamp endTime) {
-        return getDataForPV(pvName, startTime, endTime, false, null);
-    }
-
-    @Override
-    public GenMsgIterator getDataForPV(
-            String pvName, Timestamp startTime, Timestamp endTime, boolean useReducedDataSet) {
-        return getDataForPV(pvName, startTime, endTime, useReducedDataSet, null);
-    }
-
-    @Override
-    public GenMsgIterator getDataForPV(
-            String pvName,
+    public final GenMsgIterator getDataForPVs(
+            List<String> pvNames,
             Timestamp startTime,
             Timestamp endTime,
             boolean useReducedDataSet,
             Map<String, String> otherParams) {
         // We'll use java.net for now.
         StringWriter buf = new StringWriter();
-        String encode = URLEncoder.encode(pvName, StandardCharsets.UTF_8);
         buf.append(accessURL);
+        // If the access url has no query parameters then start new query, else append to existing
+        var first_encoded = URLEncoder.encode(pvNames.get(0), StandardCharsets.UTF_8);
         if (accessURL.contains("?")) {
-            buf.append("&pv=").append(encode);
+            buf.append("&pv=").append(first_encoded);
         } else {
-            buf.append("?pv=").append(encode);
+            buf.append("?pv=").append(first_encoded);
+        }
+        for (var pvName: pvNames) {
+            buf.append("&pv=").append(URLEncoder.encode(pvName, StandardCharsets.UTF_8));
         }
         buf.append("&from=").append(convertToUTC(startTime)).append("&to=").append(convertToUTC(endTime));
         if (useReducedDataSet) {