ikrs.httpd.resource
Class ProcessableResource

java.lang.Object
  ikrs.httpd.resource.AbstractResource
      ikrs.httpd.resource.ProcessableResource

All Implemented Interfaces:

Resource

public class ProcessableResource
extends AbstractResource

Processable resources represent system processes that generate any output which will be used as the Resource's output data. The resource expects a system command that will be executed in an external system process. The resource will read from the process' stdout and pass the received data towards the designated input stream (see Resource.getInputStream()). Note A: Failing the execution of the system command does not necessarily throw any exceptions! Use the ProcessableResource.getExitValue() method to check wheter the execution was successful. Note B: If the execution really fails, the resource contains the data from the error output (not from stdout). TAKE CARE WITH PLATFORM DEPENDENT COMMANDS!

Constructor Summary

ProcessableResource(HTTPHandler handler, CustomLogger logger, java.lang.ProcessBuilder pb, PostDataWrapper postData, boolean useFairLocks)
Create a new ProcessableResource.

Method Summary

boolean	close() Closes this resource.
int	getExitValue() Get the process's exit code after execution (after calling the open() method).
java.io.InputStream	getInputStream() Get the input stream from this resource.
long	getLength() This method returns the *actual* length of the underlying resource.
java.io.OutputStream	getOutputStream() Get the output stream to this resource.
boolean	isOpen() This method determines if this resource was alerady opened or not.
boolean	isReadOnly() This method returns true if the underlying resource is read-only (in general).
static void	main(java.lang.String[] argv) For testing only.
void	open(boolean readOnly) This method opens the underlying resource.

Methods inherited from class ikrs.httpd.resource.AbstractResource

getHTTPHandler, getHypertextAccessFile, getLogger, getMetaData, getReadLock, getWriteLock, setHypertextAccessFile

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ProcessableResource

public ProcessableResource(HTTPHandler handler,
                           CustomLogger logger,
                           java.lang.ProcessBuilder pb,
                           PostDataWrapper postData,
                           boolean useFairLocks)
                    throws java.lang.NullPointerException

Create a new ProcessableResource.

Parameters:

logger - A custom logger to write log messages to (must not be null).

pb - The process builder to use (must not be null).

useFairLocks - If set to true the class will use fair read locks (writing isn't possible at all with this class).

Throws:

java.lang.NullPointerException - If logger or pb is null.

Method Detail

getExitValue

public int getExitValue()

Get the process's exit code after execution (after calling the open() method). Note that failing to execute

open

public void open(boolean readOnly)
          throws ReadOnlyException,
                 java.io.IOException

This method opens the underlying resource. Don't forget to close.

Specified by:

open in interface Resource

Specified by:

open in class AbstractResource

Parameters:

readOnly - if set to true, the resource will be opened in read-only mode.

Throws:

ReadOnlyException - If the underlying resource is read-only in general.

java.io.IOException - If any other IO error occurs.

See Also:

isReadOnly()

isOpen

public boolean isOpen()
               throws java.io.IOException

This method determines if this resource was alerady opened or not.

Specified by:

isOpen in interface Resource

Specified by:

isOpen in class AbstractResource

Throws:

java.io.IOException - If any IO error occurs.

isReadOnly

public boolean isReadOnly()
                   throws java.io.IOException

This method returns true if the underlying resource is read-only (in general).

Specified by:

isReadOnly in interface Resource

Specified by:

isReadOnly in class AbstractResource

Throws:

java.io.IOException - If any IO error occurs.

getLength

public long getLength()
               throws java.io.IOException

This method returns the *actual* length of the underlying resource. This length will be used in the HTTP header fields to specify the transaction length. During read-process (you used the locks, didn't you?) the length MUST NOT change.

Specified by:

getLength in interface Resource

Specified by:

getLength in class AbstractResource

Returns:

the length of the resource's data in bytes.

Throws:

java.io.IOException - If any IO error occurs.

getOutputStream

public java.io.OutputStream getOutputStream()
                                     throws ReadOnlyException,
                                            java.io.IOException

Get the output stream to this resource.

Specified by:

getOutputStream in interface Resource

Specified by:

getOutputStream in class AbstractResource

Throws:

ReadOnlyException - If this resource was opened with the read-only flag set.

java.io.IOException - If any other IO error occurs.

getInputStream

public java.io.InputStream getInputStream()
                                   throws java.io.IOException

Get the input stream from this resource.

Specified by:

getInputStream in interface Resource

Specified by:

getInputStream in class AbstractResource

Throws:

java.io.IOException - If any IO error occurs.

close

public boolean close()
              throws java.io.IOException

Closes this resource.

Specified by:

close in interface Resource

Specified by:

close in class AbstractResource

Returns:

false if the resource was already closed, true otherwise.

Throws:

java.io.IOException

main

public static void main(java.lang.String[] argv)

For testing only.