From 224ef659d3508555533b023687d54a56e4432518 Mon Sep 17 00:00:00 2001
From: peng-yongsheng <8082209@qq.com>
Date: Wed, 27 Sep 2017 14:52:41 +0800
Subject: [PATCH] Fixed #438, catch null point exception when collector start
 up with standalone mode.

---
 .../ClusterStandaloneDataMonitor.java         | 71 +++++++++++++++++++
 .../ClusterStandaloneModuleDefine.java        | 10 ++-
 2 files changed, 79 insertions(+), 2 deletions(-)
 create mode 100644 apm-collector/apm-collector-cluster/src/main/java/org/skywalking/apm/collector/cluster/standalone/ClusterStandaloneDataMonitor.java

diff --git a/apm-collector/apm-collector-cluster/src/main/java/org/skywalking/apm/collector/cluster/standalone/ClusterStandaloneDataMonitor.java b/apm-collector/apm-collector-cluster/src/main/java/org/skywalking/apm/collector/cluster/standalone/ClusterStandaloneDataMonitor.java
new file mode 100644
index 000000000..99e369809
--- /dev/null
+++ b/apm-collector/apm-collector-cluster/src/main/java/org/skywalking/apm/collector/cluster/standalone/ClusterStandaloneDataMonitor.java
@@ -0,0 +1,71 @@
+package org.skywalking.apm.collector.cluster.standalone;
+
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import org.skywalking.apm.collector.client.h2.H2Client;
+import org.skywalking.apm.collector.client.zookeeper.util.PathUtils;
+import org.skywalking.apm.collector.core.CollectorException;
+import org.skywalking.apm.collector.core.client.Client;
+import org.skywalking.apm.collector.core.client.ClientException;
+import org.skywalking.apm.collector.core.client.DataMonitor;
+import org.skywalking.apm.collector.core.cluster.ClusterDataListener;
+import org.skywalking.apm.collector.core.module.ModuleRegistration;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * @author pengys5
+ */
+public class ClusterStandaloneDataMonitor implements DataMonitor {
+
+    private final Logger logger = LoggerFactory.getLogger(ClusterStandaloneDataMonitor.class);
+
+    private H2Client client;
+
+    private Map<String, ClusterDataListener> listeners;
+    private Map<String, ModuleRegistration> registrations;
+
+    public ClusterStandaloneDataMonitor() {
+        listeners = new LinkedHashMap<>();
+        registrations = new LinkedHashMap<>();
+    }
+
+    @Override public void setClient(Client client) {
+        this.client = (H2Client)client;
+    }
+
+    @Override
+    public void addListener(ClusterDataListener listener, ModuleRegistration registration) throws ClientException {
+        String path = PathUtils.convertKey2Path(listener.path());
+        logger.info("listener path: {}", path);
+        listeners.put(path, listener);
+        registrations.put(path, registration);
+    }
+
+    @Override public ClusterDataListener getListener(String path) {
+        path = PathUtils.convertKey2Path(path);
+        return listeners.get(path);
+    }
+
+    @Override public void createPath(String path) throws ClientException {
+
+    }
+
+    @Override public void setData(String path, String value) throws ClientException {
+        if (listeners.containsKey(path)) {
+            listeners.get(path).addAddress(value);
+            listeners.get(path).serverJoinNotify(value);
+        }
+    }
+
+    @Override public void start() throws CollectorException {
+        Iterator<Map.Entry<String, ModuleRegistration>> entryIterator = registrations.entrySet().iterator();
+        while (entryIterator.hasNext()) {
+            Map.Entry<String, ModuleRegistration> next = entryIterator.next();
+            ModuleRegistration.Value value = next.getValue().buildValue();
+            String contextPath = value.getContextPath() == null ? "" : value.getContextPath();
+            setData(next.getKey(), value.getHostPort() + contextPath);
+        }
+    }
+}
diff --git a/apm-collector/apm-collector-cluster/src/main/java/org/skywalking/apm/collector/cluster/standalone/ClusterStandaloneModuleDefine.java b/apm-collector/apm-collector-cluster/src/main/java/org/skywalking/apm/collector/cluster/standalone/ClusterStandaloneModuleDefine.java
index d8572a4f4..90533e067 100644
--- a/apm-collector/apm-collector-cluster/src/main/java/org/skywalking/apm/collector/cluster/standalone/ClusterStandaloneModuleDefine.java
+++ b/apm-collector/apm-collector-cluster/src/main/java/org/skywalking/apm/collector/cluster/standalone/ClusterStandaloneModuleDefine.java
@@ -15,6 +15,12 @@ public class ClusterStandaloneModuleDefine extends ClusterModuleDefine {
 
     public static final String MODULE_NAME = "standalone";
 
+    private final ClusterStandaloneDataMonitor dataMonitor;
+
+    public ClusterStandaloneModuleDefine() {
+        this.dataMonitor = new ClusterStandaloneDataMonitor();
+    }
+
     @Override public String group() {
         return ClusterModuleGroupDefine.GROUP_NAME;
     }
@@ -32,7 +38,7 @@ public class ClusterStandaloneModuleDefine extends ClusterModuleDefine {
     }
 
     @Override public DataMonitor dataMonitor() {
-        return null;
+        return dataMonitor;
     }
 
     @Override protected Client createClient() {
@@ -40,6 +46,6 @@ public class ClusterStandaloneModuleDefine extends ClusterModuleDefine {
     }
 
     @Override public ClusterModuleRegistrationReader registrationReader() {
-        return null;
+        return new ClusterStandaloneModuleRegistrationReader(dataMonitor);
     }
 }
-- 
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