1 files changed, 61 insertions, 47 deletions

diff --git a/config-model/src/main/java/com/yahoo/config/model/provision/Hosts.java b/config-model/src/main/java/com/yahoo/config/model/provision/Hosts.java
index 1a145e6c83e..bfb77612d31 100644
--- a/config-model/src/main/java/com/yahoo/config/model/provision/Hosts.java
+++ b/config-model/src/main/java/com/yahoo/config/model/provision/Hosts.java
@@ -1,9 +1,8 @@
 // Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.config.model.provision;
 
-import com.google.common.collect.ImmutableMap;
-import com.yahoo.cloud.config.ConfigserverConfig;
 import com.yahoo.config.model.builder.xml.XmlHelper;
+import com.yahoo.log.LogLevel;
 import com.yahoo.net.HostName;
 import com.yahoo.text.XML;
 import com.yahoo.vespa.model.builder.xml.dom.VespaDomBuilder;
@@ -18,60 +17,26 @@ import java.util.*;
 import java.util.logging.Logger;
 
 /**
- * A collection of hosts
+ * TODO: What is this?
  *
- * @author bratseth
+ * @author hmusum
  */
 public class Hosts {
 
     public static final Logger log = Logger.getLogger(Hosts.class.getPackage().toString());
 
-    private final ImmutableMap<String, Host> hosts;
+    private final HashMap<String, Host> hosts = new LinkedHashMap<>();
+    private final Map<String, String> alias2hostname = new LinkedHashMap<>();
+    private final Map<String, Host> alias2host = new LinkedHashMap<>();
 
-    public Hosts(Collection<Host> hosts) {
-        validateAliases(hosts);
-        
-        ImmutableMap.Builder<String, Host> hostsBuilder = new ImmutableMap.Builder<>();
-        for (Host host : hosts)
-            hostsBuilder.put(host.hostname(), host);
-        this.hosts = hostsBuilder.build();
-
-        System.setProperty("zookeeper.vespa.clients", toHostnameString(hosts)); // See com.yahoo.vespa.zookeeper.ZooKeeperServer
-    }
-
-    /** Throw IllegalArgumentException if host aliases breaks invariants */
-    private void validateAliases(Collection<Host> hosts) {
-        Set<String> aliases = new HashSet<>();
-        for (Host host : hosts) {
-            if (host.aliases().size() > 0) {
-                if (host.aliases().size() < 1)
-                    throw new IllegalArgumentException("Host '" + host.hostname() + "' must have at least one <alias> tag.");
-                for (String alias : host.aliases()) {
-                    if (aliases.contains(alias))
-                        throw new IllegalArgumentException("Alias '" + alias + "' is used by multiple hosts.");
-                    aliases.add(alias);
-                }
-            }
-        }
-    }
-    
-    private String toHostnameString(Collection<Host> hosts) {
-        StringBuilder b = new StringBuilder();
-        for (Host host : hosts)
-            b.append(host.hostname()).append(",");
-        if (b.length() > 0)
-            b.setLength(b.length() - 1); // remove last comma
-        return b.toString();
-    }
-    
     /**
      * Builds host system from a hosts.xml file
      *
      * @param hostsFile a reader for host from application package
      * @return the HostSystem for this application package
      */
-    public static Hosts readFrom(Reader hostsFile) {
-        List<Host> hosts = new ArrayList<>();
+    public static Hosts getHosts(Reader hostsFile) {
+        Hosts hosts = new Hosts();
         Document doc;
         try {
             doc = XmlHelper.getDocumentBuilder().parse(new InputSource(hostsFile));
@@ -90,13 +55,62 @@ public class Hosts {
             if (hostAliases.isEmpty()) {
                 throw new IllegalArgumentException("No host aliases defined for host '" + name + "'");
             }
-            hosts.add(new Host(name, hostAliases));
+            Host host = new Host(name, hostAliases);
+            hosts.addHost(host, hostAliases);
+        }
+        log.log(LogLevel.DEBUG, "Created hosts:" + hosts);
+        return hosts;
+    }
+
+    public Collection<Host> getHosts() {
+        return hosts.values();
+    }
+
+    /**
+     * Adds one host to this host system.
+     *
+     * @param host    The host to add
+     * @param aliases The aliases for this host.
+     */
+    public void addHost(Host host, List<String> aliases) {
+        hosts.put(host.getHostname(), host);
+        if ((aliases != null) && (aliases.size() > 0)) {
+            addHostAliases(aliases, host);
         }
-        return new Hosts(hosts);
     }
 
-    /** Returns an immutable collection of the hosts of this */
-    public Collection<Host> asCollection() { return hosts.values(); }
+    /**
+     * Add all aliases for one host
+     *
+     * @param hostAliases A list of host aliases
+     * @param host        The Host instance to add the alias for
+     */
+    private void addHostAliases(List<String> hostAliases, Host host) {
+        if (hostAliases.size() < 1) {
+            throw new RuntimeException("Host '" + host.getHostname() + "' must have at least one <alias> tag.");
+        }
+        for (String alias : hostAliases) {
+            addHostAlias(alias, host);
+        }
+    }
+
+    /**
+     * Adds an alias for the given host
+     *
+     * @param alias alias (string) for a Host
+     * @param host  the {@link Host} to add the alias for
+     */
+    protected void addHostAlias(String alias, Host host) {
+        if (alias2hostname.containsKey(alias)) {
+            throw new RuntimeException("Alias '" + alias + "' must be used for only one host!");
+        }
+        alias2hostname.put(alias, host.getHostname());
+        alias2host.put(alias, host);
+    }
+
+    public Map<String, Host> getAlias2host() {
+        return alias2host;
+    }
 
     @Override
     public String toString() {