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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.messagebus.routing;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
/**
* At any time there may only ever be zero or one routing table registered in message bus for each protocol. This class
* contains a list of named hops and routes that may be used to substitute references to these during route resolving.
*
* @author Simon Thoresen Hult
*/
public class RoutingTable {
private final Map<String, HopBlueprint> hops = new LinkedHashMap<>();
private final Map<String, Route> routes = new LinkedHashMap<>();
/**
* Creates a new routing table based on a given specification. This also verifies the integrity of the table.
*
* @param spec The specification to use.
*/
public RoutingTable(RoutingTableSpec spec) {
for (int i = 0; i < spec.getNumHops(); ++i) {
HopSpec hopSpec = spec.getHop(i);
hops.put(hopSpec.getName(), new HopBlueprint(hopSpec));
}
for (int i = 0; i < spec.getNumRoutes(); ++i) {
RouteSpec routeSpec = spec.getRoute(i);
Route route = new Route();
for (int j = 0; j < routeSpec.getNumHops(); ++j) {
route.addHop(Hop.parse(routeSpec.getHop(j)));
}
routes.put(routeSpec.getName(), route);
}
}
/**
* Returns whether or not there are any hops in this routing table.
*
* @return True if there is at least one hop.
*/
public boolean hasHops() {
return !hops.isEmpty();
}
/**
* Returns the number of hops that are contained in this.
*
* @return The number of hops.
*/
public int getNumHops() {
return hops.size();
}
/**
* Returns an iterator for the hops of this table.
*
* @return An iterator.
*/
public HopIterator getHopIterator() {
return new HopIterator(hops);
}
/**
* Returns an iterator for the routes of this table.
*
* @return An iterator.
*/
public RouteIterator getRouteIterator() {
return new RouteIterator(routes);
}
/**
* Returns whether or not there are any routes in this routing table.
*
* @return True if there is at least one route.
*/
public boolean hasRoutes() {
return !routes.isEmpty();
}
/**
* Returns the number of routes that are contained in this.
*
* @return The number of routes.
*/
public int getNumRoutes() {
return routes.size();
}
/**
* Returns whether or not there exists a named hop in this.
*
* @param name The name of the hop to look for.
* @return True if the named hop exists.
*/
public boolean hasHop(String name) {
return hops.containsKey(name);
}
/**
* Returns the named hop, may be null.
*
* @param name The name of the hop to return.
* @return The hop implementation object.
*/
public HopBlueprint getHop(String name) {
return hops.get(name);
}
/**
* Returns whether or not there exists a named route in this.
*
* @param name The name of the route to look for.
* @return True if the named route exists.
*/
public boolean hasRoute(String name) {
return routes.containsKey(name);
}
/**
* Returns the named route, may be null.
*
* @param name The name of the route to return.
* @return The route implementation object.
*/
public Route getRoute(String name) {
return routes.get(name);
}
@Override
public String toString() {
StringBuilder ret = new StringBuilder("RoutingTable(hops = { ");
int i = 0;
for (String name : hops.keySet()) {
ret.append("'").append(name).append("' : ").append(hops.get(name));
if (i++ < hops.size() - 1) {
ret.append(", ");
}
}
ret.append(" }, routes = { ");
i = 0;
for (String name : routes.keySet()) {
ret.append("'").append(name).append("' : ").append(routes.get(name));
if (i++ < routes.size()) {
ret.append(", ");
}
}
ret.append(" })");
return ret.toString();
}
/**
* Implements an iterator for the hops of this. Use {@link RoutingTable#getHopIterator()}
* to retrieve an instance of this.
*/
public static class HopIterator {
private Iterator<Map.Entry<String, HopBlueprint>> it;
private Map.Entry<String, HopBlueprint> entry;
/**
* Constructs a new iterator based on a given map. This is private so that only a {@link RoutingTable} can
* create one.
*
* @param hops the map to iterate through
*/
private HopIterator(Map<String, HopBlueprint> hops) {
it = hops.entrySet().iterator();
next();
}
/** Steps to the next hop in the map. */
public void next() {
entry = it.hasNext() ? it.next() : null;
}
/** Returns whether this iterator is valid. */
public boolean isValid() {
return entry != null;
}
/** Returns the name of the current hop. */
public String getName() {
return entry.getKey();
}
/** Returns the current hop. */
public HopBlueprint getHop() {
return entry.getValue();
}
}
/**
* Implements an iterator for the routes of this. Use {@link RoutingTable#getRouteIterator()}
* to retrieve an instance of this.
*/
public static class RouteIterator {
private Iterator<Map.Entry<String, Route>> it;
private Map.Entry<String, Route> entry;
/**
* Constructs a new iterator based on a given map. This is private so that only a {@link RoutingTable} can
* create one.
*
* @param routes the map to iterate through
*/
private RouteIterator(Map<String, Route> routes) {
it = routes.entrySet().iterator();
next();
}
/** Steps to the next route in the map. */
public void next() {
entry = it.hasNext() ? it.next() : null;
}
/** Returns whether this iterator is valid. */
public boolean isValid() {
return entry != null;
}
/** Returns the name of the current route. */
public String getName() {
return entry.getKey();
}
/** Returns the current route. */
public Route getRoute() {
return entry.getValue();
}
}
}
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