DPML Notify

[niclas AT hedhman.org]

Author: niclas AT hedhman.org
Date: Fri Jun 10 11:04:32 2005
New Revision: 2819

Added:
   development/planet/components/console/commands/src/test/
   development/planet/components/console/commands/src/test/net/
   development/planet/components/console/commands/src/test/net/dpml/
   development/planet/components/console/commands/src/test/net/dpml/console/
   
development/planet/components/console/commands/src/test/net/dpml/console/test/
   
development/planet/components/console/commands/src/test/net/dpml/console/test/EchoCommandTestCase.java
   (contents, props changed)
   
development/planet/components/console/commands/src/test/net/dpml/console/test/TestCommandInterpreter.java
   (contents, props changed)
   
development/planet/components/console/commands/src/test/net/dpml/console/test/TestConsole.java
   (contents, props changed)
Modified:
   development/planet/components/console/blocks/default/build.xml
   
development/planet/components/console/commands/src/main/net/dpml/console/commands/DeployCmd.java
   
development/planet/components/console/commands/src/main/net/dpml/console/commands/DummyCmd.java
   
development/planet/components/console/commands/src/main/net/dpml/console/commands/EchoCmd.java
   
development/planet/components/console/commands/src/main/net/dpml/console/commands/ExitCmd.java
   
development/planet/components/console/commands/src/main/net/dpml/console/commands/HelpCmd.java
   
development/planet/components/console/commands/src/main/net/dpml/console/commands/ListCmd.java
   
development/planet/components/console/commands/src/main/net/dpml/console/commands/RedeployCmd.java
   
development/planet/components/console/commands/src/main/net/dpml/console/commands/SelectCmd.java
   
development/planet/components/console/commands/src/main/net/dpml/console/commands/ShowModelCmd.java
   
development/planet/components/console/commands/src/main/net/dpml/console/commands/ThreadCmd.java
   
development/planet/components/console/commands/src/main/net/dpml/console/commands/UndeployCmd.java
   
development/planet/components/console/impl/src/main/net/dpml/console/impl/LoginCmd.java
   development/planet/components/console/index.xml
   
development/planet/components/console/xmpp/src/main/net/dpml/console/xmpp/XmppProvider.java
   
development/planet/components/console/xmpp/src/main/net/dpml/console/xmpp/XmppWriter.java
Log:
Some steps towards testing, and a functional default block.

Modified: development/planet/components/console/blocks/default/build.xml
==============================================================================
--- development/planet/components/console/blocks/default/build.xml      
(original)
+++ development/planet/components/console/blocks/default/build.xml      Fri 
Jun 10 11:04:32 2005
@@ -14,10 +14,26 @@
       <x:component name="console" 
            class="net.dpml.console.impl.ConsoleImpl" >
         <x:parameters>
-          <x:parameter name="port" value="3333"/>
           <x:parameter name="welcome-text" 
              value="Welcome to Metro Console.
-type help for more info."/>
+After logging in, you can type help for more info."/>
+        </x:parameters>
+      </x:component>
+      
+      <x:component name="socket-connection"  
class="net.dpml.console.socket.SocketProvider" >
+        <x:parameters>
+          <x:parameter name="port" value="3333"/>
+        </x:parameters>
+        <x:configuration>
+        </x:configuration>
+      </x:component>
+      
+      <x:component name="xmpp-connection"  
class="net.dpml.console.xmpp.XmppProvider" >
+        <x:parameters>
+          <x:parameter name="jabber-server" value="jabber.dpml.net"/>
+          <x:parameter name="jabber-port" value="5222"/>
+          <x:parameter name="_user" 
value="RemoveUnderscoreFromUserToEnable"/>
+          <x:parameter name="password" value="UnsafePassword"/>
         </x:parameters>
       </x:component>
       
@@ -42,13 +58,13 @@
       <x:component name="help" 
                    class="net.dpml.console.commands.HelpCmd"/>
                    
-      <x:component name="list" 
+      <x:component name="ls" 
                    class="net.dpml.console.commands.ListCmd"/>
     
       <x:component name="show model" 
                    class="net.dpml.console.commands.ShowModelCmd"/>
     
-      <x:component name="select" 
+      <x:component name="cd" 
                    class="net.dpml.console.commands.SelectCmd"/>
     
       <x:component name="deploy block" 

Modified: 
development/planet/components/console/commands/src/main/net/dpml/console/commands/DeployCmd.java
==============================================================================
--- 
development/planet/components/console/commands/src/main/net/dpml/console/commands/DeployCmd.java
    (original)
+++ 
development/planet/components/console/commands/src/main/net/dpml/console/commands/DeployCmd.java
    Fri Jun 10 11:04:32 2005
@@ -63,16 +63,16 @@
      *
      * @exception ContextException if a contextualization error occurs
      *
-     * @metro.entry key="urn:avalon:name" 
+     * @metro.entry key="urn:metro:name" 
      *               type="java.lang.String" 
-     * @metro.entry key="urn:avalon:home" 
+     * @metro.entry key="urn:metro:home" 
      *               type="java.io.File" 
      */
     public void contextualize( Context ctx ) 
         throws ContextException
     {
-        m_Name = (String) ctx.get( "urn:avalon:name" );
-        m_WorkingDir = (File) ctx.get( "urn:avalon:home" );
+        m_Name = (String) ctx.get( "urn:metro:name" );
+        m_WorkingDir = (File) ctx.get( "urn:metro:home" );
     }
 
     /**

Modified: 
development/planet/components/console/commands/src/main/net/dpml/console/commands/DummyCmd.java
==============================================================================
--- 
development/planet/components/console/commands/src/main/net/dpml/console/commands/DummyCmd.java
     (original)
+++ 
development/planet/components/console/commands/src/main/net/dpml/console/commands/DummyCmd.java
     Fri Jun 10 11:04:32 2005
@@ -60,13 +60,13 @@
      *
      * @exception ContextException if a contextualization error occurs
      *
-     * @metro.entry key="urn:avalon:name" 
+     * @metro.entry key="urn:metro:name" 
      *               type="java.lang.String" 
      */
     public void contextualize( Context ctx ) 
         throws ContextException
     {
-        m_Name = (String) ctx.get( "urn:avalon:name" );
+        m_Name = (String) ctx.get( "urn:metro:name" );
     }
 
     

Modified: 
development/planet/components/console/commands/src/main/net/dpml/console/commands/EchoCmd.java
==============================================================================
--- 
development/planet/components/console/commands/src/main/net/dpml/console/commands/EchoCmd.java
      (original)
+++ 
development/planet/components/console/commands/src/main/net/dpml/console/commands/EchoCmd.java
      Fri Jun 10 11:04:32 2005
@@ -59,13 +59,13 @@
      *
      * @exception ContextException if a contextualization error occurs
      *
-     * @metro.entry key="urn:avalon:name" 
+     * @metro.entry key="urn:metro:name" 
      *               type="java.lang.String" 
      */
     public void contextualize( Context ctx ) 
         throws ContextException
     {
-        m_Name = (String) ctx.get( "urn:avalon:name" );
+        m_Name = (String) ctx.get( "urn:metro:name" );
     }
 
     /**

Modified: 
development/planet/components/console/commands/src/main/net/dpml/console/commands/ExitCmd.java
==============================================================================
--- 
development/planet/components/console/commands/src/main/net/dpml/console/commands/ExitCmd.java
      (original)
+++ 
development/planet/components/console/commands/src/main/net/dpml/console/commands/ExitCmd.java
      Fri Jun 10 11:04:32 2005
@@ -59,13 +59,13 @@
      *
      * @exception ContextException if a contextualization error occurs
      *
-     * @metro.entry key="urn:avalon:name" 
+     * @metro.entry key="urn:metro:name" 
      *               type="java.lang.String" 
      */
     public void contextualize( Context ctx ) 
         throws ContextException
     {
-        m_Name = (String) ctx.get( "urn:avalon:name" );
+        m_Name = (String) ctx.get( "urn:metro:name" );
     }
 
     /**

Modified: 
development/planet/components/console/commands/src/main/net/dpml/console/commands/HelpCmd.java
==============================================================================
--- 
development/planet/components/console/commands/src/main/net/dpml/console/commands/HelpCmd.java
      (original)
+++ 
development/planet/components/console/commands/src/main/net/dpml/console/commands/HelpCmd.java
      Fri Jun 10 11:04:32 2005
@@ -63,13 +63,13 @@
      *
      * @exception ContextException if a contextualization error occurs
      *
-     * @metro.entry key="urn:avalon:name" 
+     * @metro.entry key="urn:metro:name" 
      *               type="java.lang.String" 
      */
     public void contextualize( Context ctx ) 
         throws ContextException
     {
-        m_Name = (String) ctx.get( "urn:avalon:name" );
+        m_Name = (String) ctx.get( "urn:metro:name" );
     }
 
     /**

Modified: 
development/planet/components/console/commands/src/main/net/dpml/console/commands/ListCmd.java
==============================================================================
--- 
development/planet/components/console/commands/src/main/net/dpml/console/commands/ListCmd.java
      (original)
+++ 
development/planet/components/console/commands/src/main/net/dpml/console/commands/ListCmd.java
      Fri Jun 10 11:04:32 2005
@@ -62,13 +62,13 @@
      *
      * @exception ContextException if a contextualization error occurs
      *
-     * @metro.entry key="urn:avalon:name" 
+     * @metro.entry key="urn:metro:name" 
      *               type="java.lang.String" 
      */
     public void contextualize( Context ctx ) 
         throws ContextException
     {
-        m_Name = (String) ctx.get( "urn:avalon:name" );
+        m_Name = (String) ctx.get( "urn:metro:name" );
     }
 
     /**

Modified: 
development/planet/components/console/commands/src/main/net/dpml/console/commands/RedeployCmd.java
==============================================================================
--- 
development/planet/components/console/commands/src/main/net/dpml/console/commands/RedeployCmd.java
  (original)
+++ 
development/planet/components/console/commands/src/main/net/dpml/console/commands/RedeployCmd.java
  Fri Jun 10 11:04:32 2005
@@ -59,16 +59,16 @@
      *
      * @exception ContextException if a contextualization error occurs
      *
-     * @metro.entry key="urn:avalon:name" 
+     * @metro.entry key="urn:metro:name" 
      *               type="java.lang.String" 
-     * @metro.entry key="urn:avalon:home" 
+     * @metro.entry key="urn:metro:home" 
      *               type="java.io.File" 
      */
     public void contextualize( Context ctx ) 
         throws ContextException
     {
-        m_Name = (String) ctx.get( "urn:avalon:name" );
-        m_WorkingDir = (File) ctx.get( "urn:avalon:home" );
+        m_Name = (String) ctx.get( "urn:metro:name" );
+        m_WorkingDir = (File) ctx.get( "urn:metro:home" );
     }
 
     /**

Modified: 
development/planet/components/console/commands/src/main/net/dpml/console/commands/SelectCmd.java
==============================================================================
--- 
development/planet/components/console/commands/src/main/net/dpml/console/commands/SelectCmd.java
    (original)
+++ 
development/planet/components/console/commands/src/main/net/dpml/console/commands/SelectCmd.java
    Fri Jun 10 11:04:32 2005
@@ -62,13 +62,13 @@
      *
      * @exception ContextException if a contextualization error occurs
      *
-     * @metro.entry key="urn:avalon:name" 
+     * @metro.entry key="urn:metro:name" 
      *               type="java.lang.String" 
      */
     public void contextualize( Context ctx ) 
         throws ContextException
     {
-        m_Name = (String) ctx.get( "urn:avalon:name" );
+        m_Name = (String) ctx.get( "urn:metro:name" );
     }
 
     /**

Modified: 
development/planet/components/console/commands/src/main/net/dpml/console/commands/ShowModelCmd.java
==============================================================================
--- 
development/planet/components/console/commands/src/main/net/dpml/console/commands/ShowModelCmd.java
 (original)
+++ 
development/planet/components/console/commands/src/main/net/dpml/console/commands/ShowModelCmd.java
 Fri Jun 10 11:04:32 2005
@@ -63,13 +63,13 @@
      *
      * @exception ContextException if a contextualization error occurs
      *
-     * @metro.entry key="urn:avalon:name" 
+     * @metro.entry key="urn:metro:name" 
      *               type="java.lang.String" 
      */
     public void contextualize( Context ctx ) 
         throws ContextException
     {
-        m_Name = (String) ctx.get( "urn:avalon:name" );
+        m_Name = (String) ctx.get( "urn:metro:name" );
     }
 
     /**

Modified: 
development/planet/components/console/commands/src/main/net/dpml/console/commands/ThreadCmd.java
==============================================================================
--- 
development/planet/components/console/commands/src/main/net/dpml/console/commands/ThreadCmd.java
    (original)
+++ 
development/planet/components/console/commands/src/main/net/dpml/console/commands/ThreadCmd.java
    Fri Jun 10 11:04:32 2005
@@ -59,13 +59,13 @@
      *
      * @exception ContextException if a contextualization error occurs
      *
-     * @metro.entry key="urn:avalon:name" 
+     * @metro.entry key="urn:metro:name" 
      *               type="java.lang.String" 
      */
     public void contextualize( Context ctx ) 
         throws ContextException
     {
-        m_Name = (String) ctx.get( "urn:avalon:name" );
+        m_Name = (String) ctx.get( "urn:metro:name" );
     }
 
     /**

Modified: 
development/planet/components/console/commands/src/main/net/dpml/console/commands/UndeployCmd.java
==============================================================================
--- 
development/planet/components/console/commands/src/main/net/dpml/console/commands/UndeployCmd.java
  (original)
+++ 
development/planet/components/console/commands/src/main/net/dpml/console/commands/UndeployCmd.java
  Fri Jun 10 11:04:32 2005
@@ -60,13 +60,13 @@
      *
      * @exception ContextException if a contextualization error occurs
      *
-     * @metro.entry key="urn:avalon:name" 
+     * @metro.entry key="urn:metro:name" 
      *               type="java.lang.String" 
      */
     public void contextualize( Context ctx ) 
         throws ContextException
     {
-        m_Name = (String) ctx.get( "urn:avalon:name" );
+        m_Name = (String) ctx.get( "urn:metro:name" );
     }
 
     /**

Added: 
development/planet/components/console/commands/src/test/net/dpml/console/test/EchoCommandTestCase.java
==============================================================================
--- (empty file)
+++ 
development/planet/components/console/commands/src/test/net/dpml/console/test/EchoCommandTestCase.java
      Fri Jun 10 11:04:32 2005
@@ -0,0 +1,73 @@
+/*
+ * Copyright 2004 Niclas Hedman.
+ * 
+ * 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 net.dpml.console.test;
+
+import java.io.*;
+import java.util.*;
+import junit.framework.TestCase;
+
+import net.dpml.context.*;
+import net.dpml.service.*;
+import net.dpml.metro.unit.*;
+
+import net.dpml.console.*;
+import net.dpml.console.commands.*;
+
+public class EchoCommandTestCase extends TestCase
+{
+    private final String IN_DATA = "This is a TEST with Svenska åäöÅÄÖ.";
+    
+    private EchoCmd m_Command;
+    private CommandInterpreter m_Intp;
+    
+    private ByteArrayOutputStream m_OutBuffer;
+    private BufferedReader m_Reader;
+    private BufferedWriter m_Writer;
+    
+    public void setUp()
+        throws Exception
+    {
+        Context ctx = new TestContext();
+        Console console = new TestConsole();
+        HashMap deps = new HashMap();
+        deps.put( "console", console );
+        ServiceManager man = new TestServiceManager( deps );
+        m_Command = new EchoCmd();
+        m_Command.contextualize( ctx );
+        m_Command.service( man );
+        m_Intp = new TestCommandInterpreter();
+        
+        ByteArrayInputStream in = new ByteArrayInputStream( 
IN_DATA.getBytes() );
+        InputStreamReader isr = new InputStreamReader( in, "UTF-8" );
+        m_Reader = new BufferedReader( isr );
+        
+        m_OutBuffer = new ByteArrayOutputStream();
+        OutputStreamWriter osw = new OutputStreamWriter( m_OutBuffer, 
"UTF-8" );
+        m_Writer = new BufferedWriter( osw );
+    }
+    
+    public void testCommand()
+        throws Exception
+    {
+        assertEquals( "name", "unit-test", m_Command.getName() );
+        assertEquals( "description", "usage: unit-test (string)*\n\nSends 
each of the string arguments back separate by a space.", 
m_Command.getDescription() );
+        String[] args = new String[] { IN_DATA, "abc", "def" };
+        m_Command.execute( m_Intp,  m_Reader, m_Writer, args );
+        byte[] data = m_OutBuffer.toByteArray();
+        String result = new String( data, "UTF-8" ).trim();
+        assertEquals( "data", "echo:  " + IN_DATA + " abc def", result );
+    }
+}
\ No newline at end of file

Added: 
development/planet/components/console/commands/src/test/net/dpml/console/test/TestCommandInterpreter.java
==============================================================================
--- (empty file)
+++ 
development/planet/components/console/commands/src/test/net/dpml/console/test/TestCommandInterpreter.java
   Fri Jun 10 11:04:32 2005
@@ -0,0 +1,72 @@
+/*
+ * Copyright 2005 Niclas Hedman.
+ * 
+ * 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 net.dpml.console.test;
+
+import java.util.*; 
+
+import net.dpml.composition.model.ContainmentModel;
+
+import net.dpml.console.ConsoleCommand;
+import net.dpml.console.CommandInterpreter;
+
+public class TestCommandInterpreter
+    implements CommandInterpreter
+{
+    private HashMap m_Commands;
+    private ContainmentModel m_Node;
+    
+    TestCommandInterpreter()
+    {
+        m_Commands = new HashMap();
+    }
+    
+    public void addCommand( ConsoleCommand cmd )
+    {
+        String name = cmd.getName();
+        m_Commands.put( name, cmd );
+    }
+    
+    public void removeCommand( ConsoleCommand cmd )
+    {
+        String name = cmd.getName();
+        removeCommand( name );
+    }
+    
+    public void removeCommand( String name )
+    {
+        m_Commands.remove( name );
+    }
+    
+    public ConsoleCommand getCommand( String name )
+    {
+        return (ConsoleCommand) m_Commands.get( name );
+    }
+    
+    public void close()
+    {
+    }
+    
+    public ContainmentModel getCurrentContainer()
+    {
+        return m_Node;
+    }
+    
+    public void setCurrentContainer( ContainmentModel node )
+    {
+        m_Node = node;
+    }
+    
+} 

Added: 
development/planet/components/console/commands/src/test/net/dpml/console/test/TestConsole.java
==============================================================================
--- (empty file)
+++ 
development/planet/components/console/commands/src/test/net/dpml/console/test/TestConsole.java
      Fri Jun 10 11:04:32 2005
@@ -0,0 +1,59 @@
+/*
+ * Copyright 2005 Niclas Hedman.
+ * 
+ * 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 net.dpml.console.test;
+
+import java.util.*; 
+
+import net.dpml.console.Console; 
+import net.dpml.console.ConsoleCommand; 
+
+class TestConsole
+    implements Console
+{
+    private HashMap m_Commands;
+    
+    TestConsole()
+    {
+        m_Commands = new HashMap();
+    }
+    
+    public void addCommand( ConsoleCommand cmd )
+    {
+        String name = cmd.getName();
+        m_Commands.put( name, cmd );
+    }
+    
+    public void removeCommand( ConsoleCommand cmd )
+    {
+        String name = cmd.getName();
+        removeCommand( name );
+    }
+    
+    public void removeCommand( String name )
+    {
+        m_Commands.remove( name );
+    }
+    
+    public ConsoleCommand getCommand( String name )
+    {
+        return (ConsoleCommand) m_Commands.get( name );
+    }
+    
+    public Collection getCommandNames()
+    {
+        return m_Commands.keySet();
+    }
+}

Modified: 
development/planet/components/console/impl/src/main/net/dpml/console/impl/LoginCmd.java
==============================================================================
--- 
development/planet/components/console/impl/src/main/net/dpml/console/impl/LoginCmd.java
     (original)
+++ 
development/planet/components/console/impl/src/main/net/dpml/console/impl/LoginCmd.java
     Fri Jun 10 11:04:32 2005
@@ -22,15 +22,15 @@
 import net.dpml.console.Console;
 import net.dpml.console.ConsoleCommand;
 import net.dpml.console.LoginException;
+
 import net.dpml.context.Context;
 import net.dpml.context.ContextException;
-import net.dpml.context.Contextualizable;
+
 import net.dpml.parameters.ParameterException;
-import net.dpml.parameters.Parameterizable;
 import net.dpml.parameters.Parameters;
+
 import net.dpml.service.ServiceException;
 import net.dpml.service.ServiceManager;
-import net.dpml.service.Serviceable;
 
 /**
  * @metro.component name="console-login" lifestyle="singleton"
@@ -56,6 +56,9 @@
     public LoginCmd( Context ctx, Parameters params, ServiceManager man )
         throws ContextException, ParameterException, ServiceException
     {
+        // TODO; LoginCmd should use JAAS to establish a proper 
+        //       login and security context.
+        
         m_Name = (String) ctx.get( "urn:metro:name" );
         m_Password = params.getParameter( "root-password" );
         Console console = (Console) man.lookup( "console" );

Modified: development/planet/components/console/index.xml
==============================================================================
--- development/planet/components/console/index.xml     (original)
+++ development/planet/components/console/index.xml     Fri Jun 10 11:04:32 
2005
@@ -84,6 +84,8 @@
     </info>
     <dependencies>
       <include key="dpml-console-impl"/>
+      <include key="dpml-classic-api"/>
+      <include key="dpml-classic-unit"/>
     </dependencies>
     <plugins>
       <include key="dpml-meta-tools"/>
@@ -96,7 +98,7 @@
       <type>block</type>
     </info>
     <dependencies>
-            <include key="dpml-console-commands"/>
+      <include key="dpml-console-commands"/>
     </dependencies>
     <plugins>
       <include key="dpml-meta-tools"/>

Modified: 
development/planet/components/console/xmpp/src/main/net/dpml/console/xmpp/XmppProvider.java
==============================================================================
--- 
development/planet/components/console/xmpp/src/main/net/dpml/console/xmpp/XmppProvider.java
 (original)
+++ 
development/planet/components/console/xmpp/src/main/net/dpml/console/xmpp/XmppProvider.java
 Fri Jun 10 11:04:32 2005
@@ -96,7 +96,7 @@
         m_Listeners = new ArrayList();
         m_Server = params.getParameter( "jabber-server" );
         m_Port = params.getParameterAsInteger( "jabber-port" );
-        m_User = params.getParameter( "user" );
+        m_User = params.getParameter( "user", 
InetAddress.getLocalHost().toString() );
         m_Password = params.getParameter( "password" );
         connectToJabberServer();        
     }

Modified: 
development/planet/components/console/xmpp/src/main/net/dpml/console/xmpp/XmppWriter.java
==============================================================================
--- 
development/planet/components/console/xmpp/src/main/net/dpml/console/xmpp/XmppWriter.java
   (original)
+++ 
development/planet/components/console/xmpp/src/main/net/dpml/console/xmpp/XmppWriter.java
   Fri Jun 10 11:04:32 2005
@@ -34,7 +34,7 @@
     public void newLine()
         throws IOException
     {
-        flush();
+        m_Buffer.append( "\n" );
     }
     
     public void write( char[] ch, int offset, int length )