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Posted to common-user@hadoop.apache.org by Nan Zhu <zh...@gmail.com> on 2013/12/15 01:53:03 UTC

manipulate DFSInputStream in FSDataInputStream?

Hi, all  

I’m modifying FSDataInputStream for some project,  

I would like to directly manipulate “in" object in my implementation  

as in the constructor a DFSInputStream is passed, so I convert “in” from InputStream to DFSInputStream with  

import org.apache.hadoop.hdfs.DFSClient;

DFSClient.DFSInputStream dins = (DFSClient.DFSInputStream) in;
dins.somemethod(…)


when I compile my code with ant

it says that  

[javac] /Users/zhunan/codes/SDNBigData/hadoop-1.2.1/src/core/org/apache/hadoop/fs/FSDataInputStream.java:20: error: package org.apache.hadoop.hdfs does not exist  
    [javac] import org.apache.hadoop.hdfs.DFSClient;



What does this mean?

it means that core is compiled before hdfs, so I cannot do this?

Thank you very much!

Best,

--  
Nan Zhu
School of Computer Science,
McGill University

Re: manipulate DFSInputStream in FSDataInputStream?

Posted by Nan Zhu <zh...@gmail.com>.
Solved by declare an empty somemethod() in FSInputStream and override it in DFSInputStream  



--  
Nan Zhu
School of Computer Science,
McGill University



On Saturday, December 14, 2013 at 7:53 PM, Nan Zhu wrote:

> Hi, all  
>  
> I’m modifying FSDataInputStream for some project,  
>  
> I would like to directly manipulate “in" object in my implementation  
>  
> as in the constructor a DFSInputStream is passed, so I convert “in” from InputStream to DFSInputStream with  
>  
> import org.apache.hadoop.hdfs.DFSClient;
>  
> DFSClient.DFSInputStream dins = (DFSClient.DFSInputStream) in;
> dins.somemethod(…)
>  
>  
> when I compile my code with ant
>  
> it says that  
>  
> [javac] /Users/zhunan/codes/SDNBigData/hadoop-1.2.1/src/core/org/apache/hadoop/fs/FSDataInputStream.java:20: error: package org.apache.hadoop.hdfs does not exist  
>     [javac] import org.apache.hadoop.hdfs.DFSClient;
>  
>  
>  
> What does this mean?
>  
> it means that core is compiled before hdfs, so I cannot do this?
>  
> Thank you very much!
>  
> Best,
>  
> --  
> Nan Zhu
> School of Computer Science,
> McGill University
>

Re: manipulate DFSInputStream in FSDataInputStream?

Posted by Nan Zhu <zh...@gmail.com>.
Solved by declare an empty somemethod() in FSInputStream and override it in DFSInputStream  



--  
Nan Zhu
School of Computer Science,
McGill University



On Saturday, December 14, 2013 at 7:53 PM, Nan Zhu wrote:

> Hi, all  
>  
> I’m modifying FSDataInputStream for some project,  
>  
> I would like to directly manipulate “in" object in my implementation  
>  
> as in the constructor a DFSInputStream is passed, so I convert “in” from InputStream to DFSInputStream with  
>  
> import org.apache.hadoop.hdfs.DFSClient;
>  
> DFSClient.DFSInputStream dins = (DFSClient.DFSInputStream) in;
> dins.somemethod(…)
>  
>  
> when I compile my code with ant
>  
> it says that  
>  
> [javac] /Users/zhunan/codes/SDNBigData/hadoop-1.2.1/src/core/org/apache/hadoop/fs/FSDataInputStream.java:20: error: package org.apache.hadoop.hdfs does not exist  
>     [javac] import org.apache.hadoop.hdfs.DFSClient;
>  
>  
>  
> What does this mean?
>  
> it means that core is compiled before hdfs, so I cannot do this?
>  
> Thank you very much!
>  
> Best,
>  
> --  
> Nan Zhu
> School of Computer Science,
> McGill University
>

Re: manipulate DFSInputStream in FSDataInputStream?

Posted by Nan Zhu <zh...@gmail.com>.
Solved by declare an empty somemethod() in FSInputStream and override it in DFSInputStream  



--  
Nan Zhu
School of Computer Science,
McGill University



On Saturday, December 14, 2013 at 7:53 PM, Nan Zhu wrote:

> Hi, all  
>  
> I’m modifying FSDataInputStream for some project,  
>  
> I would like to directly manipulate “in" object in my implementation  
>  
> as in the constructor a DFSInputStream is passed, so I convert “in” from InputStream to DFSInputStream with  
>  
> import org.apache.hadoop.hdfs.DFSClient;
>  
> DFSClient.DFSInputStream dins = (DFSClient.DFSInputStream) in;
> dins.somemethod(…)
>  
>  
> when I compile my code with ant
>  
> it says that  
>  
> [javac] /Users/zhunan/codes/SDNBigData/hadoop-1.2.1/src/core/org/apache/hadoop/fs/FSDataInputStream.java:20: error: package org.apache.hadoop.hdfs does not exist  
>     [javac] import org.apache.hadoop.hdfs.DFSClient;
>  
>  
>  
> What does this mean?
>  
> it means that core is compiled before hdfs, so I cannot do this?
>  
> Thank you very much!
>  
> Best,
>  
> --  
> Nan Zhu
> School of Computer Science,
> McGill University
>

Re: manipulate DFSInputStream in FSDataInputStream?

Posted by Nan Zhu <zh...@gmail.com>.
Solved by declare an empty somemethod() in FSInputStream and override it in DFSInputStream  



--  
Nan Zhu
School of Computer Science,
McGill University



On Saturday, December 14, 2013 at 7:53 PM, Nan Zhu wrote:

> Hi, all  
>  
> I’m modifying FSDataInputStream for some project,  
>  
> I would like to directly manipulate “in" object in my implementation  
>  
> as in the constructor a DFSInputStream is passed, so I convert “in” from InputStream to DFSInputStream with  
>  
> import org.apache.hadoop.hdfs.DFSClient;
>  
> DFSClient.DFSInputStream dins = (DFSClient.DFSInputStream) in;
> dins.somemethod(…)
>  
>  
> when I compile my code with ant
>  
> it says that  
>  
> [javac] /Users/zhunan/codes/SDNBigData/hadoop-1.2.1/src/core/org/apache/hadoop/fs/FSDataInputStream.java:20: error: package org.apache.hadoop.hdfs does not exist  
>     [javac] import org.apache.hadoop.hdfs.DFSClient;
>  
>  
>  
> What does this mean?
>  
> it means that core is compiled before hdfs, so I cannot do this?
>  
> Thank you very much!
>  
> Best,
>  
> --  
> Nan Zhu
> School of Computer Science,
> McGill University
>