AdminTool internals refactorings

This makes it slightly easier to test command providers, and also aligns the visibilities.
For instance, methods that returned `Result` objects were publicly visible, while the `Result` interface was private.

community/command-line/src/main/java/org/neo4j/commandline/admin/AdminTool.java

@@ -23,13 +23,8 @@
 import java.nio.file.Paths;
 import java.util.Arrays;
 import java.util.NoSuchElementException;
-import java.util.Objects;
-import java.util.function.Function;
 import java.util.function.Supplier;
 
-import org.neo4j.helpers.Service;
-import org.neo4j.helpers.collection.Iterables;
-
 import static java.lang.String.format;
 
 public class AdminTool
@@ -41,9 +36,9 @@ public static void main( String[] args )
         String extraHelp = System.getenv( "NEO4J_EXTRA_HELP" );
         boolean debug = System.getenv( "NEO4J_DEBUG" ) != null;
 
-        new AdminTool( new ServiceCommandLocator(), System.out::println, extraHelp, debug )
-                .execute( homeDir, configDir, args )
-                .exit();
+        AdminTool tool = new AdminTool( CommandLocator.fromServiceLocator(), System.out::println, extraHelp, debug );
+        Result result = tool.execute( homeDir, configDir, args );
+        result.exit();
     }
 
     private final String scriptName = "neo4j-admin";
@@ -54,7 +49,7 @@ public static void main( String[] args )
 
     public AdminTool( CommandLocator locator, Output out, String extraHelp, boolean debug )
     {
-        this.locator = new AppendingLocator( help(), locator );
+        this.locator = CommandLocator.withAdditionalCommand( help(), locator );
         this.out = out;
         this.debug = debug;
         this.usage = new Usage( scriptName, out, this.locator, extraHelp );
@@ -153,54 +148,4 @@ private static Result success()
     {
         return () -> System.exit( 0 );
     }
-
-    private interface Result
-    {
-        void exit();
-    }
-
-    public interface CommandLocator
-            extends Function<String, AdminCommand.Provider>, Supplier<Iterable<AdminCommand.Provider>>
-    {
-    }
-
-    private static class ServiceCommandLocator implements CommandLocator
-    {
-        @Override
-        public AdminCommand.Provider apply( String name )
-        {
-            return Service.load( AdminCommand.Provider.class, name );
-        }
-
-        @Override
-        public Iterable<AdminCommand.Provider> get()
-        {
-            return Service.load( AdminCommand.Provider.class );
-        }
-    }
-
-    private class AppendingLocator implements CommandLocator
-    {
-        private final Supplier<AdminCommand.Provider> command;
-        private final CommandLocator commands;
-
-        public AppendingLocator( Supplier<AdminCommand.Provider> command, CommandLocator commands )
-        {
-            this.command = command;
-            this.commands = commands;
-        }
-
-        @Override
-        public AdminCommand.Provider apply( String name )
-        {
-            AdminCommand.Provider provider = command.get();
-            return Objects.equals( name, provider.name() ) ? provider : commands.apply( name );
-        }
-
-        @Override
-        public Iterable<AdminCommand.Provider> get()
-        {
-            return Iterables.append( command.get(), commands.get() );
-        }
-    }
 }

community/command-line/src/main/java/org/neo4j/commandline/admin/CommandLocator.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2002-2016 "Neo Technology,"
+ * Network Engine for Objects in Lund AB [http://neotechnology.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Neo4j is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.neo4j.commandline.admin;
+
+import java.util.Objects;
+import java.util.function.Function;
+import java.util.function.Supplier;
+
+import org.neo4j.helpers.Service;
+import org.neo4j.helpers.collection.Iterables;
+
+/**
+ * The CommandLocator locates named commands for the AdminTool, or supplies the set of available commands for printing
+ * help output.
+ */
+public interface CommandLocator
+        extends Function<String, AdminCommand.Provider>, Supplier<Iterable<AdminCommand.Provider>>
+{
+
+    static CommandLocator fromServiceLocator()
+    {
+        return new CommandLocator()
+        {
+            @Override
+            public AdminCommand.Provider apply( String name )
+            {
+                return Service.load( AdminCommand.Provider.class, name );
+            }
+
+            @Override
+            public Iterable<AdminCommand.Provider> get()
+            {
+                return Service.load( AdminCommand.Provider.class );
+            }
+        };
+    }
+
+    static CommandLocator withAdditionalCommand( Supplier<AdminCommand.Provider> command, CommandLocator commands )
+    {
+        return new CommandLocator()
+        {
+            @Override
+            public AdminCommand.Provider apply( String name )
+            {
+                AdminCommand.Provider provider = command.get();
+                return Objects.equals( name, provider.name() ) ? provider : commands.apply( name );
+            }
+
+            @Override
+            public Iterable<AdminCommand.Provider> get()
+            {
+                return Iterables.append( command.get(), commands.get() );
+            }
+        };
+    }
+}

community/command-line/src/main/java/org/neo4j/commandline/admin/Result.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2002-2016 "Neo Technology,"
+ * Network Engine for Objects in Lund AB [http://neotechnology.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Neo4j is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.neo4j.commandline.admin;
+
+/**
+ * The result of an admin command execution, with a delayed program termination action.
+ */
+public interface Result
+{
+    void exit();
+}

community/command-line/src/test/java/org/neo4j/commandline/admin/AdminToolTest.java

@@ -94,7 +94,7 @@ public void line( String text )
         }
     }
 
-    private static class CannedLocator implements AdminTool.CommandLocator
+    private static class CannedLocator implements CommandLocator
     {
         private final RecordingCommand command;
 
@@ -116,7 +116,7 @@ public Iterable<AdminCommand.Provider> get()
         }
     }
 
-    private static class NullCommandLocator implements AdminTool.CommandLocator
+    private static class NullCommandLocator implements CommandLocator
     {
         @Override
         public AdminCommand.Provider apply( String s )