Merge IntentInstaller's role into IntentCompiler

It resolves naming mismatch in naming of IntentProcessPhases and states
handled in the phases. It is described in ONOS-1064.

- Define FlowRuleIntent that enables flow rule level operation
  as an intent.
- Remove IntentInstaller interface
- Existing installable intents such as PathIntent, LinkCollectionIntent,
  OpticalPathIntent and MplsPathIntent now become non installable intents.
  Only FlowRuleIntent is categorized as installable intent now.
- Implement intent compilers for PathIntent, LinkCollectionIntent,
  OpticalPathIntent and MplsPathIntent. They generates FlowRuleIntents.
- Write unit tests for the newly created intent compilers according to
  the intent installers' unit tests
- Remove all intent installers and their unit tests

Change-Id: I22d6c7acb65a4c066145de0018bd0727f44bd54a
diff --git a/core/net/src/main/java/org/onosproject/net/intent/impl/phase/Replacing.java b/core/net/src/main/java/org/onosproject/net/intent/impl/phase/Replacing.java
new file mode 100644
index 0000000..911139c
--- /dev/null
+++ b/core/net/src/main/java/org/onosproject/net/intent/impl/phase/Replacing.java
@@ -0,0 +1,62 @@
+/*
+ * 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.intent.IntentData;
+import org.onosproject.net.intent.IntentException;
+import org.onosproject.net.intent.impl.IntentProcessor;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Optional;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Represents a phase to replace an intent.
+ */
+final class Replacing implements IntentProcessPhase {
+
+    private static final Logger log = LoggerFactory.getLogger(Replacing.class);
+
+    private final IntentProcessor processor;
+    private final IntentData data;
+    private final IntentData stored;
+
+    /**
+     * Creates a replacing phase.
+     *
+     * @param processor intent processor that does work for replacing
+     * @param data      intent data containing an intent to be replaced
+     * @param stored    intent data stored in the store
+     */
+    Replacing(IntentProcessor processor, IntentData data, IntentData stored) {
+        this.processor = checkNotNull(processor);
+        this.data = checkNotNull(data);
+        this.stored = checkNotNull(stored);
+    }
+
+    @Override
+    public Optional<IntentProcessPhase> execute() {
+        try {
+            processor.uninstall(stored);
+            return Optional.of(new Installing(processor, data));
+        } catch (IntentException e) {
+            log.warn("Unable to generate a FlowRuleOperations from intent {} due to:", data.intent().id(), e);
+            return Optional.of(new ReplaceFailed(data));
+        }
+    }
+}