info.sswap.ontologies.exec.impl
Class ExecImpl

java.lang.Object
  javax.servlet.GenericServlet
      javax.servlet.http.HttpServlet
          info.sswap.api.servlet.AbstractSSWAPServlet
              info.sswap.ontologies.exec.impl.ExecImpl

All Implemented Interfaces:

Exec, HotboxPoller, java.io.Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig

Direct Known Subclasses:

ExecServlet

public class ExecImpl
extends AbstractSSWAPServlet
implements Exec, HotboxPoller

Implementation for ExecServlet.

See Also:

ExecServlet, Serialized Form

Field Summary

private static int	BLOCK_SIZ Limits on user-supplied arguments: size, length, and number
private static int	EOF
private java.lang.String	hotboxPath Optional "hotboxPath" as defined in web.xml.
(package private) HotboxPoller	hotboxPoller The hotbox poller; may be null if not invoked
private static int	MAX_ARG_LENGTH
private static long	MAX_BLOCKS
private static int	MAX_NUM_ARGS
private java.lang.String	rdgPath "RDGPath" as defined in web.xml.
private static long	serialVersionUID
private java.io.File	tmpDir Temporary working directory (TWD) for the executed process.

Fields inherited from class info.sswap.api.servlet.AbstractSSWAPServlet

remoteServiceURI, RRG_RETRIEVAL_SUFFIX

Constructor Summary

ExecImpl()

Method Summary

private void	close(java.io.OutputStream stdin, java.io.InputStream stdout, java.io.InputStream stderr) Close streams to release resources and flush output.
private void	fillPipe(java.io.InputStream inputStream, java.io.OutputStream stdin) Byte-count limited transferring of bytes from the inputStream to the outputStream.
java.lang.String[]	getCommandLine(java.lang.String commandLineStr) Basic parsing and sanity checking of the command line.
private java.lang.String	getStrValue(SSWAPNode sswapNode, java.net.URI ontologyPredicate) Get a String value from a property.
protected void	handleRequest(RIG rig) This method is marked protected solely for package access purposes and should not be called directly nor overridden.
void	init(javax.servlet.ServletConfig servletConfig) Internal initialization for HttpServlet.
boolean	isRunning() Check if the hotbox poller is running.
void	setEnvironment(java.util.Map<java.lang.String,java.lang.String> env) Set the process' execution environment.
void	setInterval(int sleepSeconds) Set the delay interval between directory scans.
void	start() Start the hotbox directory polling.
private java.lang.Process	startProcess(java.lang.String[] commandLine) Start the process.
void	stop() Stop the hotbox directory polling.
private void	validateArgs(java.lang.String[] args) Simple argument sanity checking.

Methods inherited from class info.sswap.api.servlet.AbstractSSWAPServlet

doGet, doPost, getTimeout, setTimeout

Methods inherited from class javax.servlet.http.HttpServlet

doDelete, doHead, doOptions, doPut, doTrace, getLastModified, service, service

Methods inherited from class javax.servlet.GenericServlet

destroy, getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, log, log

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

BLOCK_SIZ

private static final int BLOCK_SIZ

Limits on user-supplied arguments: size, length, and number

See Also:

Constant Field Values

MAX_BLOCKS

private static final long MAX_BLOCKS

See Also:

Constant Field Values

EOF

private static final int EOF

See Also:

Constant Field Values

MAX_ARG_LENGTH

private static final int MAX_ARG_LENGTH

See Also:

Constant Field Values

MAX_NUM_ARGS

private static final int MAX_NUM_ARGS

See Also:

Constant Field Values

rdgPath

private java.lang.String rdgPath

"RDGPath" as defined in web.xml. This is the path to the "public" directory where the RDF/XML RDGs reside.

hotboxPath

private java.lang.String hotboxPath

Optional "hotboxPath" as defined in web.xml. This is the directory that is polled (scanned every interval) for JSON files awaiting conversion to RDGs, to be placed in the public folder.

hotboxPoller

HotboxPoller hotboxPoller

The hotbox poller; may be null if not invoked

tmpDir

private java.io.File tmpDir

Temporary working directory (TWD) for the executed process. Each process invocation gets a new TWD; TWD is recursively deleted upon normal or exception exit.

Constructor Detail

ExecImpl

public ExecImpl()

Method Detail

init

public void init(javax.servlet.ServletConfig servletConfig)
          throws javax.servlet.ServletException

Internal initialization for HttpServlet. This method is marked public solely for package access purposes and should not be called directly nor overridden.

Specified by:

init in interface javax.servlet.Servlet

Overrides:

init in class AbstractSSWAPServlet

Parameters:

servletConfig - the ServletConfig object of the servlet

Throws:

javax.servlet.ServletException - on a servlet configuration error

See Also:

SSWAP, ServletConfig

handleRequest

protected final void handleRequest(RIG rig)

This method is marked protected solely for package access purposes and should not be called directly nor overridden.

Specified by:

handleRequest in class AbstractSSWAPServlet

Parameters:

rig - RIG invoking the service. This RIG should be edited and will become the basis for the RRG returned by the service. Best practice is to leave most of the RIG untouched, modifying only the SSWAPObject subgraphs.

See Also:

RIG, RRG, RequestEntityTooLargeException, ClientException

getCommandLine

public java.lang.String[] getCommandLine(java.lang.String commandLineStr)
                                  throws TooManyArgumentsException,
                                         ArgumentTooLongException

Description copied from interface: Exec

Basic parsing and sanity checking of the command line. Parsing implies deconstructing a single string into a string array analogous to the array argument passed to Java main(). Override this method to validate, sanitize, and otherwise change the command and the user arguments.

Specified by:

getCommandLine in interface Exec

Parameters:

commandLineStr - a concatenation of the RDG's exec:command and the RIG's exec:args.

Returns:

Java main() equivalent of command line arguments. The command itself must be the first element.

Throws:

TooManyArgumentsException - if the number of arguments exceeds a preset maximum

ArgumentTooLongException - if an argument exceeds a preset maximum

setEnvironment

public void setEnvironment(java.util.Map<java.lang.String,java.lang.String> env)

Description copied from interface: Exec

Set the process' execution environment. Override this method to set the execution environment. Default implementation is to clear the environment.

Specified by:

setEnvironment in interface Exec

Parameters:

env - the default environment ProcessBuilder environment

See Also:

ProcessBuilder.environment()

getStrValue

private java.lang.String getStrValue(SSWAPNode sswapNode,
                                     java.net.URI ontologyPredicate)

Get a String value from a property.

Parameters:

sswapNode - individual with the property

ontologyPredicate - predicate of the property

Returns:

first string value retrieved; empty string "" on any error

startProcess

private java.lang.Process startProcess(java.lang.String[] commandLine)
                                throws java.io.IOException

Start the process. This implies sending the command line to be exectued to the operating system.

Parameters:

commandLine - the command and its arguments to be executed

Returns:

the Process object for process control

Throws:

java.io.IOException - on any error to execute the process

validateArgs

private void validateArgs(java.lang.String[] args)
                   throws TooManyArgumentsException,
                          ArgumentTooLongException

Simple argument sanity checking.

Parameters:

args - array of arguments, not including the command itself

Throws:

TooManyArgumentsException - if the number of arguments exceeds a preset maximum

ArgumentTooLongException - if the length of any argument exceeds a preset maximum

fillPipe

private void fillPipe(java.io.InputStream inputStream,
                      java.io.OutputStream stdin)
               throws java.io.IOException

Byte-count limited transferring of bytes from the inputStream to the outputStream.

Parameters:

inputStream - data to read

stdin - stream to write

Throws:

java.io.IOException - on any error

close

private void close(java.io.OutputStream stdin,
                   java.io.InputStream stdout,
                   java.io.InputStream stderr)

Close streams to release resources and flush output.

Parameters:

stdin - output stream accepting data as input to send to process to execute

stdout - input stream for reading data from executed process

stderr - input stream for reading error messages from executed process

start

public void start()

Description copied from interface: HotboxPoller

Start the hotbox directory polling.

Specified by:

start in interface HotboxPoller

setInterval

public void setInterval(int sleepSeconds)

Description copied from interface: HotboxPoller

Set the delay interval between directory scans.

Specified by:

setInterval in interface HotboxPoller

Parameters:

sleepSeconds - number of seconds to wait between polling

stop

public void stop()

Description copied from interface: HotboxPoller

Stop the hotbox directory polling.

Specified by:

stop in interface HotboxPoller

isRunning

public boolean isRunning()

Description copied from interface: HotboxPoller

Check if the hotbox poller is running.

Specified by:

isRunning in interface HotboxPoller

Returns:

true if running; false if stopped; e.g., because it was never started or because it was stopped (interrupted).