org.gm4java.engine

Interface GMService

All Superinterfaces:

GMExecutor

All Known Implementing Classes:

PooledGMService, SimpleGMService

public interface GMService
extends GMExecutor

Defines the GraphicsMagick service interface.

Implementations of this interface must ensure all the methods defined in this interface are thread safe.

Author:

Kenneth Xu

Method Summary

Methods

Modifier and Type	Method and Description
String	execute(List<String> command) Executes the command using the underlying GraphicsMagick process.
String	execute(String command, String... arguments) Executes the GraphisMagick command and return the result.
GMConnection	getConnection() Gets an instance of GMConnection.

Method Detail

execute

String execute(@Nonnull
             String command,
             String... arguments)
               throws IOException,
                      GMException,
                      GMServiceException

Executes the GraphisMagick command and return the result.

This is a convenient method to get the connection, execute the command once and close it. It is functionally equivalent to code below, but actual implementation may optimize this for better efficiency.

 final GMConnection connection = gmService.getConnection();
 try {
     return connection.execute(command, argument1, argument2, ...);
 } finally {
     connection.close();
 }
 

This method is thread safe.

Specified by:

execute in interface GMExecutor

Parameters:

command - the command to be executed

arguments - arguments of the command.

Returns:

the output from GraphicsMagick as the result of executing the command

Throws:

NullPointerException - when command is null

IOException - when GM encounter IO error executing the command

GMException - when GraphicsMagick returns non-IO error executing the command

GMServiceException - when there is error communicating with the underlying GraphicsMagick process

See Also:

GMExecutor.execute(List)

execute

String execute(@Nonnull
             List<String> command)
               throws IOException,
                      GMException,
                      GMServiceException

Executes the command using the underlying GraphicsMagick process. GraphicsMagick command and its arguments are passed in as a list of strings.

This is a convenient method to get the connection, execute the command once and close it. It is functionally equivalent to code below, but actual implementation may optimize this for better efficiency.

 final GMConnection connection = gmService.getConnection();
 try {
     return connection.execute(command);
 } finally {
     connection.close();
 }
 

This method is thread safe.

Specified by:

execute in interface GMExecutor

Parameters:

command - the command and arguments to be executed

Returns:

the output from GraphicsMagick as the result of executing the command

Throws:

NullPointerException - when command is null

IllegalArgumentException - when command is an empty list.

IOException - when GM encounter IO error executing the command

GMException - when GraphicsMagick returns non-IO error executing the command

GMServiceException - when there is error communicating with the underlying GraphicsMagick process

See Also:

execute(String, String...)

getConnection

@Nonnull
GMConnection getConnection()
                           throws GMServiceException

Gets an instance of GMConnection. Depends on the implementation, the instance can be newly created or from a pool.

This method is thread safe.

Returns:

an instance of GMConnection

Throws:

GMServiceException - when communicate error occurs between the physical GraphicsMagick process.