Add support for JSON state.

Use Jackson for serialization and deserialization of JSON objects.

2 files changed, 125 insertions, 75 deletions

diff --git a/same/src/main/java/com/orbekk/same/MasterServiceImpl.java b/same/src/main/java/com/orbekk/same/MasterServiceImpl.java
index 64cde2f..50a5607 100644
--- a/same/src/main/java/com/orbekk/same/MasterServiceImpl.java
+++ b/same/src/main/java/com/orbekk/same/MasterServiceImpl.java
@@ -1,5 +1,7 @@
 package com.orbekk.same;
 
+import java.util.List;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -12,9 +14,22 @@ public class MasterServiceImpl implements MasterService, UrlReceiver {
     }
     
     @Override
-    public void joinNetworkRequest(String networkName, String clientUrl) {
-        // TODO Auto-generated method stub
-        
+    public synchronized void joinNetworkRequest(String networkName, String clientUrl) {
+        if (networkName.equals(state.getDataOf(".networkName"))) {
+            List<String> participants = state.getList(".participants");
+            if (!participants.contains(clientUrl)) {
+                participants.add(clientUrl);
+            } else {                
+                logger.warn("Client {} already part of network. " +
+                        "Ignoring participation request", clientUrl);
+            }
+            state.updateFromObject(".participants", participants,
+                    state.getRevision(".participants"));
+        } else {
+            logger.warn("Client {} tried to join {}, but network name is {}",
+                    new Object[]{ clientUrl, networkName, 
+                            state.getDataOf(".networkName") });
+        }
     }
 
     @Override
diff --git a/same/src/main/java/com/orbekk/same/State.java b/same/src/main/java/com/orbekk/same/State.java
index 6b7c824..303caca 100644
--- a/same/src/main/java/com/orbekk/same/State.java
+++ b/same/src/main/java/com/orbekk/same/State.java
@@ -1,17 +1,29 @@
 package com.orbekk.same;
 
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Map;
 import java.util.HashMap;
 
+import org.codehaus.jackson.JsonGenerationException;
+import org.codehaus.jackson.JsonParseException;
+import org.codehaus.jackson.map.JsonMappingException;
+import org.codehaus.jackson.map.ObjectMapper;
+import org.codehaus.jackson.type.TypeReference;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 public class State {
+    private Logger logger = LoggerFactory.getLogger(getClass());
     private Map<String, Component> state = new HashMap<String, Component>(); 
-    
-    private long stateIteration = 0;
-    private Map<String, String> participants = new HashMap<String, String>();
-    private String networkName = "";
-    private String masterId = "";
-    private String data = "";
+    private ObjectMapper mapper = new ObjectMapper();
 
+    public State(String networkName) {
+        update(".networkName", networkName, 0);
+        updateFromObject(".participants", new ArrayList<String>(), 0);
+    }
+    
     public boolean update(String componentName, String data, long revision) {
         Component component = null;
         if (!state.containsKey(componentName)) {
@@ -39,6 +51,65 @@ public class State {
         }
     }
     
+    public long getRevision(String componentName) {
+        Component component = state.get(componentName);
+        if (component != null) {
+            return component.getRevision();
+        } else {
+            logger.warn("getRevision: Unknown component {}. Returning 0",
+                    componentName);
+            return 0;
+        }
+    }
+    
+    /**
+     * Parses a JSON value using Jackson ObjectMapper.
+     */
+    public <T> T getParsedData(String componentName, TypeReference<T> type) {
+        String data = getDataOf(componentName);
+        if (data != null) {
+            try {
+                return mapper.readValue(data, type);
+            } catch (JsonParseException e) {
+                logger.warn("Failed to parse value {} ", data);
+                logger.warn("Parse exception: {}", e);
+            } catch (JsonMappingException e) {
+                logger.warn("Failed to parse value {} ", data);
+                logger.warn("Parse exception: {}", e);
+
+            } catch (IOException e) {
+                logger.warn("Failed to parse value {} ", data);
+                logger.warn("Parse exception: {}", e);
+            }
+        }
+        return null;
+    }
+    
+    public List<String> getList(String componentName) {
+        return getParsedData(componentName,
+                new TypeReference<List<String>>(){});
+    }
+    
+    public boolean updateFromObject(String componentName, Object data, long revision) {
+        String dataS;
+        try {
+            dataS = mapper.writeValueAsString(data);
+            return update(componentName, dataS, revision);
+        } catch (JsonGenerationException e) {
+            logger.warn("Failed to convert to JSON: {} ", data);
+            logger.warn("Parse exception: {}", e);
+            return false;
+        } catch (JsonMappingException e) {
+            logger.warn("Failed to convert to JSON: {} ", data);
+            logger.warn("Parse exception: {}", e);
+            return false;
+        } catch (IOException e) {
+            logger.warn("Failed to convert to JSON: {} ", data);
+            logger.warn("Parse exception: {}", e);
+            return false;
+        }
+    }
+    
     public static class Component {
         private long revision;
         private String data;
@@ -66,70 +137,34 @@ public class State {
             return this.data + " @" + revision;
         }
     }
-    
-    public long getStateIteration() {
-        return stateIteration;
-    }
-
-    public void setStateIteration(long stateIteration) {
-        this.stateIteration = stateIteration;
-    }
-
-    public Map<String, String> getParticipants() {
-        return participants;
-    }
-
-    public String getNetworkName() {
-        return networkName;
-    }
-
-    public void setNetworkName(String networkName) {
-        this.networkName = networkName;
-    }
-
-    public String getMasterId() {
-        return masterId;
-    }
-
-    public void setMasterId(String masterId) {
-        this.masterId = masterId;
-    }
-
-    public String getData() {
-        return data;
-    }
-
-    public void setData(String data) {
-        this.data = data;
-    }
-
-    @Override
-    public String toString() {
-        StringBuilder participantsString = new StringBuilder();
-        participantsString.append("[");
-        boolean first = true;
-        for (Map.Entry<String, String> e : participants.entrySet()) {
-            if (!first) {
-                participantsString.append(", ");
-            }
-            first = false;
-            participantsString.append(e.getKey())
-                    .append("(")
-                    .append(e.getValue())
-                    .append(")");
-            String clientId = e.getKey();
-            String url = e.getValue();
-        }
-        participantsString.append("]");
-
-        return String.format(
-            "State( \n" +
-            "      stateIteration = %d,\n" +
-            "      networkName    = %s,\n" +
-            "      masterId       = %s,\n" +
-            "      data           = %s,\n" +
-            "      participants   = %s\n" +
-            ")", stateIteration, networkName, masterId, data,
-            participantsString);
-    }
+//    
+//    @Override
+//    public String toString() {
+//        StringBuilder participantsString = new StringBuilder();
+//        participantsString.append("[");
+//        boolean first = true;
+//        for (Map.Entry<String, String> e : participants.entrySet()) {
+//            if (!first) {
+//                participantsString.append(", ");
+//            }
+//            first = false;
+//            participantsString.append(e.getKey())
+//                    .append("(")
+//                    .append(e.getValue())
+//                    .append(")");
+//            String clientId = e.getKey();
+//            String url = e.getValue();
+//        }
+//        participantsString.append("]");
+//
+//        return String.format(
+//            "State( \n" +
+//            "      stateIteration = %d,\n" +
+//            "      networkName    = %s,\n" +
+//            "      masterId       = %s,\n" +
+//            "      data           = %s,\n" +
+//            "      participants   = %s\n" +
+//            ")", stateIteration, networkName, masterId, data,
+//            participantsString);
+//    }
 }