Pull out inner IntentUpdate sub-classes from IntentManager

Change-Id: Iefec2e3d5929d0e85e40bee24ba4fd0679c13b19
diff --git a/core/net/src/main/java/org/onosproject/net/intent/impl/WithdrawRequest.java b/core/net/src/main/java/org/onosproject/net/intent/impl/WithdrawRequest.java
new file mode 100644
index 0000000..dee793b
--- /dev/null
+++ b/core/net/src/main/java/org/onosproject/net/intent/impl/WithdrawRequest.java
@@ -0,0 +1,42 @@
+/*
+ * 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;
+
+import org.onosproject.net.intent.Intent;
+import org.onosproject.net.intent.IntentData;
+
+import java.util.Optional;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+class WithdrawRequest implements IntentUpdate {
+
+    // TODO: define an interface and use it, instead of IntentManager
+    private final IntentManager intentManager;
+    private final Intent intent;
+    private final IntentData currentState;
+
+    WithdrawRequest(IntentManager intentManager, Intent intent, IntentData currentState) {
+        this.intentManager = checkNotNull(intentManager);
+        this.intent = checkNotNull(intent);
+        this.currentState = currentState;
+    }
+
+    @Override
+    public Optional<IntentUpdate> execute() {
+        return Optional.of(new Withdrawing(intentManager, intent, currentState.installables())); //FIXME
+    }
+}