Added application ID store; both trivial and distributed variants.
diff --git a/core/net/src/main/java/org/onlab/onos/core/impl/CoreManager.java b/core/net/src/main/java/org/onlab/onos/core/impl/CoreManager.java
new file mode 100644
index 0000000..907466f
--- /dev/null
+++ b/core/net/src/main/java/org/onlab/onos/core/impl/CoreManager.java
@@ -0,0 +1,62 @@
+package org.onlab.onos.core.impl;
+
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Reference;
+import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.apache.felix.scr.annotations.Service;
+import org.onlab.onos.core.ApplicationId;
+import org.onlab.onos.core.ApplicationIdStore;
+import org.onlab.onos.core.CoreService;
+import org.onlab.onos.core.Version;
+import org.onlab.util.Tools;
+
+import java.io.File;
+import java.util.List;
+import java.util.Set;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Core service implementation.
+ */
+@Component
+@Service
+public class CoreManager implements CoreService {
+
+    private static final File VERSION_FILE = new File("../VERSION");
+    private static Version version = Version.version("1.0.0-SNAPSHOT");
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected ApplicationIdStore applicationIdStore;
+
+    @Activate
+    public void activate() {
+        List<String> versionLines = Tools.slurp(VERSION_FILE);
+        if (versionLines != null && !versionLines.isEmpty()) {
+            version = Version.version(versionLines.get(0));
+        }
+    }
+
+    @Override
+    public Version version() {
+        return version;
+    }
+
+    @Override
+    public Set<ApplicationId> getAppIds() {
+        return applicationIdStore.getAppIds();
+    }
+
+    @Override
+    public ApplicationId getAppId(Short id) {
+        return applicationIdStore.getAppId(id);
+    }
+
+    @Override
+    public ApplicationId registerApplication(String name) {
+        checkNotNull(name, "Application ID cannot be null");
+        return applicationIdStore.registerApplication(name);
+    }
+
+}
diff --git a/core/net/src/main/java/org/onlab/onos/impl/MetricsManagerComponent.java b/core/net/src/main/java/org/onlab/onos/core/impl/MetricsManagerComponent.java
similarity index 93%
rename from core/net/src/main/java/org/onlab/onos/impl/MetricsManagerComponent.java
rename to core/net/src/main/java/org/onlab/onos/core/impl/MetricsManagerComponent.java
index de47635..66608f2 100644
--- a/core/net/src/main/java/org/onlab/onos/impl/MetricsManagerComponent.java
+++ b/core/net/src/main/java/org/onlab/onos/core/impl/MetricsManagerComponent.java
@@ -1,4 +1,4 @@
-package org.onlab.onos.impl;
+package org.onlab.onos.core.impl;
 
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
diff --git a/core/net/src/main/java/org/onlab/onos/impl/package-info.java b/core/net/src/main/java/org/onlab/onos/core/impl/package-info.java
similarity index 62%
rename from core/net/src/main/java/org/onlab/onos/impl/package-info.java
rename to core/net/src/main/java/org/onlab/onos/core/impl/package-info.java
index 2bf17b3..8a501e3 100644
--- a/core/net/src/main/java/org/onlab/onos/impl/package-info.java
+++ b/core/net/src/main/java/org/onlab/onos/core/impl/package-info.java
@@ -1,4 +1,4 @@
 /**
  * Miscellaneous core system implementations.
  */
-package org.onlab.onos.impl;
\ No newline at end of file
+package org.onlab.onos.core.impl;
\ No newline at end of file
diff --git a/core/net/src/main/java/org/onlab/onos/impl/CoreManager.java b/core/net/src/main/java/org/onlab/onos/impl/CoreManager.java
deleted file mode 100644
index da1f8c9..0000000
--- a/core/net/src/main/java/org/onlab/onos/impl/CoreManager.java
+++ /dev/null
@@ -1,64 +0,0 @@
-package org.onlab.onos.impl;
-
-import org.apache.felix.scr.annotations.Activate;
-import org.apache.felix.scr.annotations.Component;
-import org.apache.felix.scr.annotations.Service;
-import org.onlab.onos.ApplicationId;
-import org.onlab.onos.CoreService;
-import org.onlab.onos.Version;
-import org.onlab.util.Tools;
-
-import java.io.File;
-import java.util.List;
-import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.atomic.AtomicInteger;
-
-/**
- * Core service implementation.
- */
-@Component
-@Service
-public class CoreManager implements CoreService {
-
-    private static final AtomicInteger ID_DISPENSER = new AtomicInteger(1);
-
-    private static final File VERSION_FILE = new File("../VERSION");
-    private static Version version = Version.version("1.0.0-SNAPSHOT");
-
-    private final Map<Short, DefaultApplicationId> appIds = new ConcurrentHashMap<>();
-    private final Map<String, DefaultApplicationId> appIdsByName = new ConcurrentHashMap<>();
-
-    // TODO: work in progress
-
-    @Activate
-    public void activate() {
-        List<String> versionLines = Tools.slurp(VERSION_FILE);
-        if (versionLines != null && !versionLines.isEmpty()) {
-            version = Version.version(versionLines.get(0));
-        }
-    }
-
-    @Override
-    public Version version() {
-        return version;
-    }
-
-    @Override
-    public ApplicationId getAppId(Short id) {
-        return appIds.get(id);
-    }
-
-    @Override
-    public ApplicationId registerApplication(String name) {
-        DefaultApplicationId appId = appIdsByName.get(name);
-        if (appId == null) {
-            short id = (short) ID_DISPENSER.getAndIncrement();
-            appId = new DefaultApplicationId(id, name);
-            appIds.put(id, appId);
-            appIdsByName.put(name, appId);
-        }
-        return appId;
-    }
-
-}
diff --git a/core/net/src/main/java/org/onlab/onos/impl/DefaultApplicationId.java b/core/net/src/main/java/org/onlab/onos/impl/DefaultApplicationId.java
deleted file mode 100644
index eed5fb0..0000000
--- a/core/net/src/main/java/org/onlab/onos/impl/DefaultApplicationId.java
+++ /dev/null
@@ -1,55 +0,0 @@
-package org.onlab.onos.impl;
-
-import org.onlab.onos.ApplicationId;
-
-import java.util.Objects;
-
-import static com.google.common.base.MoreObjects.toStringHelper;
-
-/**
- * Application id generator class.
- */
-public class DefaultApplicationId implements ApplicationId {
-
-    private final short id;
-    private final String name;
-
-    // Ban public construction
-    protected DefaultApplicationId(Short id, String identifier) {
-        this.id = id;
-        this.name = identifier;
-    }
-
-    @Override
-    public short id() {
-        return id;
-    }
-
-    @Override
-    public String name() {
-        return name;
-    }
-
-    @Override
-    public int hashCode() {
-        return Objects.hash(id);
-    }
-
-    @Override
-    public boolean equals(Object obj) {
-        if (this == obj) {
-            return true;
-        }
-        if (obj instanceof DefaultApplicationId) {
-            DefaultApplicationId other = (DefaultApplicationId) obj;
-            return Objects.equals(this.id, other.id);
-        }
-        return false;
-    }
-
-    @Override
-    public String toString() {
-        return toStringHelper(this).add("id", id).add("name", name).toString();
-    }
-
-}
diff --git a/core/net/src/main/java/org/onlab/onos/net/flow/impl/FlowRuleManager.java b/core/net/src/main/java/org/onlab/onos/net/flow/impl/FlowRuleManager.java
index 0c07bab..aef5831 100644
--- a/core/net/src/main/java/org/onlab/onos/net/flow/impl/FlowRuleManager.java
+++ b/core/net/src/main/java/org/onlab/onos/net/flow/impl/FlowRuleManager.java
@@ -22,7 +22,7 @@
 import org.apache.felix.scr.annotations.Reference;
 import org.apache.felix.scr.annotations.ReferenceCardinality;
 import org.apache.felix.scr.annotations.Service;
-import org.onlab.onos.ApplicationId;
+import org.onlab.onos.core.ApplicationId;
 import org.onlab.onos.event.AbstractListenerRegistry;
 import org.onlab.onos.event.EventDeliveryService;
 import org.onlab.onos.net.Device;
diff --git a/core/net/src/main/java/org/onlab/onos/net/intent/impl/LinkCollectionIntentInstaller.java b/core/net/src/main/java/org/onlab/onos/net/intent/impl/LinkCollectionIntentInstaller.java
index 2983a68..93c6345 100644
--- a/core/net/src/main/java/org/onlab/onos/net/intent/impl/LinkCollectionIntentInstaller.java
+++ b/core/net/src/main/java/org/onlab/onos/net/intent/impl/LinkCollectionIntentInstaller.java
@@ -9,8 +9,8 @@
 import org.apache.felix.scr.annotations.Deactivate;
 import org.apache.felix.scr.annotations.Reference;
 import org.apache.felix.scr.annotations.ReferenceCardinality;
-import org.onlab.onos.ApplicationId;
-import org.onlab.onos.CoreService;
+import org.onlab.onos.core.ApplicationId;
+import org.onlab.onos.core.CoreService;
 import org.onlab.onos.net.DeviceId;
 import org.onlab.onos.net.Link;
 import org.onlab.onos.net.PortNumber;
diff --git a/core/net/src/main/java/org/onlab/onos/net/intent/impl/OpticalConnectivityIntentCompiler.java b/core/net/src/main/java/org/onlab/onos/net/intent/impl/OpticalConnectivityIntentCompiler.java
index 8fcf75b..c19bba0 100644
--- a/core/net/src/main/java/org/onlab/onos/net/intent/impl/OpticalConnectivityIntentCompiler.java
+++ b/core/net/src/main/java/org/onlab/onos/net/intent/impl/OpticalConnectivityIntentCompiler.java
@@ -12,7 +12,7 @@
 import org.apache.felix.scr.annotations.Deactivate;
 import org.apache.felix.scr.annotations.Reference;
 import org.apache.felix.scr.annotations.ReferenceCardinality;
-import org.onlab.onos.CoreService;
+import org.onlab.onos.core.CoreService;
 import org.onlab.onos.net.ConnectPoint;
 import org.onlab.onos.net.Link;
 import org.onlab.onos.net.Path;
diff --git a/core/net/src/main/java/org/onlab/onos/net/intent/impl/OpticalPathIntentInstaller.java b/core/net/src/main/java/org/onlab/onos/net/intent/impl/OpticalPathIntentInstaller.java
index 5557b05..a504992 100644
--- a/core/net/src/main/java/org/onlab/onos/net/intent/impl/OpticalPathIntentInstaller.java
+++ b/core/net/src/main/java/org/onlab/onos/net/intent/impl/OpticalPathIntentInstaller.java
@@ -10,8 +10,8 @@
 import org.apache.felix.scr.annotations.Deactivate;
 import org.apache.felix.scr.annotations.Reference;
 import org.apache.felix.scr.annotations.ReferenceCardinality;
-import org.onlab.onos.ApplicationId;
-import org.onlab.onos.CoreService;
+import org.onlab.onos.core.ApplicationId;
+import org.onlab.onos.core.CoreService;
 import org.onlab.onos.net.ConnectPoint;
 import org.onlab.onos.net.Link;
 import org.onlab.onos.net.flow.DefaultFlowRule;
diff --git a/core/net/src/main/java/org/onlab/onos/net/intent/impl/PathIntentInstaller.java b/core/net/src/main/java/org/onlab/onos/net/intent/impl/PathIntentInstaller.java
index a7381b7..84e2c7c 100644
--- a/core/net/src/main/java/org/onlab/onos/net/intent/impl/PathIntentInstaller.java
+++ b/core/net/src/main/java/org/onlab/onos/net/intent/impl/PathIntentInstaller.java
@@ -11,8 +11,8 @@
 import org.apache.felix.scr.annotations.Deactivate;
 import org.apache.felix.scr.annotations.Reference;
 import org.apache.felix.scr.annotations.ReferenceCardinality;
-import org.onlab.onos.ApplicationId;
-import org.onlab.onos.CoreService;
+import org.onlab.onos.core.ApplicationId;
+import org.onlab.onos.core.CoreService;
 import org.onlab.onos.net.ConnectPoint;
 import org.onlab.onos.net.Link;
 import org.onlab.onos.net.flow.DefaultFlowRule;