Move IntentUpdate subclasses to the dedicated package

Resolve ONOS-1051
- Create package "phase" under intent.impl
- Rename IntentUpdate and CompletedIntentUpdate
  - IntentUpdate -> IntentProcessPhase
  - CompletedIntentUpdate -> FinalIntentProcessPhase
- Loosen method/field visibility as short term hack

Change-Id: Idc0fd9a74aadd227d62006d00fee473c63b1fc05
diff --git a/core/net/src/main/java/org/onosproject/net/intent/impl/phase/Installing.java b/core/net/src/main/java/org/onosproject/net/intent/impl/phase/Installing.java
new file mode 100644
index 0000000..05c499f
--- /dev/null
+++ b/core/net/src/main/java/org/onosproject/net/intent/impl/phase/Installing.java
@@ -0,0 +1,60 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.net.intent.impl.phase;
+
+import org.onosproject.net.flow.FlowRuleOperations;
+import org.onosproject.net.intent.IntentData;
+import org.onosproject.net.intent.IntentException;
+import org.onosproject.net.intent.impl.IntentManager;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Optional;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Represents a phase of installing an intent with calling
+ * {@link org.onosproject.net.flow.FlowRuleService}.
+ */
+final class Installing implements IntentProcessPhase {
+
+    private static final Logger log = LoggerFactory.getLogger(Installing.class);
+
+    private final IntentManager intentManager;
+    private final IntentData pending;
+    private final FlowRuleOperations flowRules;
+
+    // TODO: define an interface and use it, instead of IntentManager
+    Installing(IntentManager intentManager, IntentData pending, FlowRuleOperations flowRules) {
+        this.intentManager = checkNotNull(intentManager);
+        this.pending = checkNotNull(pending);
+        this.flowRules = flowRules;
+    }
+
+    @Override
+    public Optional<IntentProcessPhase> execute() {
+        try {
+            intentManager.flowRuleService.apply(flowRules); // FIXME we need to provide a context
+            return Optional.of(new Installed(pending));
+        // What kinds of exceptions are thrown by FlowRuleService.apply()?
+        // Is IntentException a correct exception abstraction?
+        } catch (IntentException e) {
+            log.warn("Unable to install intent {} due to: {}", pending.intent().id(), e);
+            return Optional.of(new InstallingFailed(pending));
+        }
+    }
+}