Added a number of container classes that will be used for
Flow Path computation and installation.
diff --git a/src/main/java/net/floodlightcontroller/util/FlowEntry.java b/src/main/java/net/floodlightcontroller/util/FlowEntry.java
new file mode 100644
index 0000000..e9c4bbe
--- /dev/null
+++ b/src/main/java/net/floodlightcontroller/util/FlowEntry.java
@@ -0,0 +1,224 @@
+package net.floodlightcontroller.util;
+
+import net.floodlightcontroller.util.Dpid;
+import net.floodlightcontroller.util.FlowEntryActions;
+import net.floodlightcontroller.util.FlowEntryId;
+import net.floodlightcontroller.util.FlowEntryMatch;
+import net.floodlightcontroller.util.Port;
+
+/**
+ * The Flow Entry state as set by the user (via the ONOS API).
+ */
+enum FlowEntryUserState {
+	FE_USER_UNKNOWN,		// Initialization value: state unknown
+	FE_USER_ADD,			// Flow entry that is added
+	FE_USER_MODIFY,			// Flow entry that is modified
+	FE_USER_DELETE			// Flow entry that is deleted
+}
+
+/**
+ * The Flow Entry state as set by the controller.
+ */
+enum FlowEntrySwitchState {
+	FE_SWITCH_UNKNOWN,		// Initialization value: state unknown
+	FE_SWITCH_NOT_UPDATED,		// Switch not updated with this entry
+	FE_SWITCH_UPDATE_IN_PROGRESS,	// Switch update in progress
+	FE_SWITCH_UPDATED,		// Switch updated with this entry
+	FE_SWITCH_UPDATE_FAILED	// Error updating the switch with this entry
+}
+
+
+/**
+ * The class representing the Flow Entry.
+ *
+ * NOTE: The specification is incomplete. E.g., the entry needs to
+ * support multiple in-ports and multiple out-ports.
+ */
+public class FlowEntry {
+    private FlowEntryId flowEntryId;		// The Flow Entry ID
+    private FlowEntryMatch flowEntryMatch;	// The Flow Entry Match
+    private FlowEntryActions flowEntryActions;	// The Flow Entry Actions
+    private Dpid dpid;				// The Switch DPID
+    private Port inPort;			// The Switch incoming port
+    private Port outPort;			// The Switch outgoing port
+    private FlowEntryUserState flowEntryUserState; // The Flow Entry User state
+    private FlowEntrySwitchState flowEntrySwitchState; // The Flow Entry Switch state
+    // The Flow Entry Error state (if FlowEntrySwitchState is FE_SWITCH_FAILED)
+    private FlowEntryErrorState flowEntryErrorState;
+
+    /**
+     * Default constructor.
+     */
+    public FlowEntry() {
+	flowEntryUserState = FlowEntryUserState.FE_USER_UNKNOWN;
+	flowEntrySwitchState = FlowEntrySwitchState.FE_SWITCH_UNKNOWN;
+    }
+
+    /**
+     * Get the Flow Entry ID.
+     *
+     * @return the Flow Entry ID.
+     */
+    public FlowEntryId flowEntryId() { return flowEntryId; }
+
+    /**
+     * Set the Flow Entry ID.
+     *
+     * @param flowEntryId the Flow Entry ID to set.
+     */
+    public void setFlowEntryId(FlowEntryId flowEntryId) {
+	this.flowEntryId = flowEntryId;
+    }
+
+    /**
+     * Get the Flow Entry Match.
+     *
+     * @return the Flow Entry Match.
+     */
+    public FlowEntryMatch flowEntryMatch() { return flowEntryMatch; }
+
+    /**
+     * Set the Flow Entry Match.
+     *
+     * @param flowEntryMatch the Flow Entry Match to set.
+     */
+    public void setFlowEntryMatch(FlowEntryMatch flowEntryMatch) {
+	this.flowEntryMatch = flowEntryMatch;
+    }
+
+    /**
+     * Get the Flow Entry Actions.
+     *
+     * @return the Flow Entry Actions.
+     */
+    public FlowEntryActions flowEntryActions() { return flowEntryActions; }
+
+    /**
+     * Set the Flow Entry Actions.
+     *
+     * @param flowEntryActions the Flow Entry Actions to set.
+     */
+    public void setFlowEntryActions(FlowEntryActions flowEntryActions) {
+	this.flowEntryActions = flowEntryActions;
+    }
+
+    /**
+     * Get the Switch DPID.
+     *
+     * @return the Switch DPID.
+     */
+    public Dpid dpid() { return dpid; }
+
+    /**
+     * Set the Switch DPID.
+     *
+     * @param dpid the Switch DPID to set.
+     */
+    public void setDpid(Dpid dpid) {
+	this.dpid = dpid;
+    }
+
+    /**
+     * Get the Switch incoming port.
+     *
+     * @return the Switch incoming port.
+     */
+    public Port inPort() { return inPort; }
+
+    /**
+     * Set the Switch incoming port.
+     *
+     * @param inPort the Switch incoming port to set.
+     */
+    public void setInPort(Port inPort) {
+	this.inPort = inPort;
+    }
+
+    /**
+     * Get the Switch outgoing port.
+     *
+     * @return the Switch outgoing port.
+     */
+    public Port outPort() { return outPort; }
+
+    /**
+     * Set the Switch outgoing port.
+     *
+     * @param outPort the Switch outgoing port to set.
+     */
+    public void setOutPort(Port outPort) {
+	this.outPort = outPort;
+    }
+
+    /**
+     * Get the Flow Entry User state.
+     *
+     * @return the Flow Entry User state.
+     */
+    public FlowEntryUserState flowEntryUserState() {
+	return flowEntryUserState;
+    }
+
+    /**
+     * Set the Flow Entry User state.
+     *
+     * @param flowEntryUserState the Flow Entry User state to set.
+     */
+    public void setFlowEntryUserState(FlowEntryUserState flowEntryUserState) {
+	this.flowEntryUserState = flowEntryUserState;
+    }
+
+    /**
+     * Get the Flow Entry Switch state.
+     *
+     * The Flow Entry Error state is used if FlowEntrySwitchState is
+     * FE_SWITCH_FAILED.
+     *
+     * @return the Flow Entry Switch state.
+     */
+    public FlowEntrySwitchState flowEntrySwitchState() {
+	return flowEntrySwitchState;
+    }
+
+    /**
+     * Set the Flow Entry Switch state.
+     *
+     * The Flow Entry Error state is used if FlowEntrySwitchState is
+     * FE_SWITCH_FAILED.
+     *
+     * @param flowEntrySwitchState the Flow Entry Switch state to set.
+     */
+    public void setFlowEntrySwitchState(FlowEntrySwitchState flowEntrySwitchState) {
+	this.flowEntrySwitchState = flowEntrySwitchState;
+    }
+
+    /**
+     * Get the Flow Entry Error state.
+     *
+     * @return the Flow Entry Error state.
+     */
+    public FlowEntryErrorState flowEntryErrorState() {
+	return flowEntryErrorState;
+    }
+
+    /**
+     * Set the Flow Entry Error state.
+     *
+     * @param flowEntryErrorState the Flow Entry Error state to set.
+     */
+    public void setFlowEntryErrorState(FlowEntryErrorState flowEntryErrorState) {
+	this.flowEntryErrorState = flowEntryErrorState;
+    }
+
+    /**
+     * Convert the flow entry to a string.
+     *
+     * @return the flow entry as a string.
+     */
+    @Override
+    public String toString() {
+	String ret = "";
+	// TODO: Implement it!
+	return ret;
+    }
+}