Package org.apache.commons.chain.generic

Class LookupCommand<C extends Context>

java.lang.Object
org.apache.commons.chain.generic.LookupCommand<C>
Type Parameters:
C - Type of the context associated with this command
All Implemented Interfaces:
Command<C>, Filter<C>
Direct Known Subclasses:
DispatchLookupCommand, PathInfoMapper, PathInfoMapper, RequestParameterMapper, RequestParameterMapper, ServletPathMapper, ServletPathMapper
public class LookupCommand<C extends Context> extends Object implements Filter<C>
Look up a specified Command (which could also be a Chain) in a Catalog, and delegate execution to it. If the delegated-to Command is also a Filter, its postprocess() method will also be invoked at the appropriate time.

The name of the Command can be specified either directly (via the name property) or indirectly (via the nameKey property). Exactly one of these must be set.

If the optional property is set to true, failure to find the specified command in the specified catalog will be silently ignored. Otherwise, a lookup failure will trigger an IllegalArgumentException.

Version:
$Revision$ $Date$
Author:
Craig R. McClanahan

  • Constructor Details

    • LookupCommand

      public LookupCommand()
      Create an instance, setting its catalogFactory property to the value of CatalogFactory.getInstance().
      Since:
      Chain 1.1

    • LookupCommand

      public LookupCommand(CatalogFactory<C> factory)
      Create an instance and initialize the catalogFactory property to given factory.
      Parameters:
      factory - The Catalog Factory.
      Since:
      Chain 1.1

  • Method Details

    • setCatalogFactory

      public void setCatalogFactory(CatalogFactory<C> catalogFactory)
      Set the CatalogFactory from which lookups will be performed.
      Parameters:
      catalogFactory - The Catalog Factory.
      Since:
      Chain 1.1

    • getCatalogFactory

      public CatalogFactory<C> getCatalogFactory()
      Return the CatalogFactory from which lookups will be performed.
      Returns:
      The Catalog factory.
      Since:
      Chain 1.1

    • getCatalogName

      public String getCatalogName()
      Return the name of the Catalog to be searched, or null to search the default Catalog.
      Returns:
      The Catalog name.

    • setCatalogName

      public void setCatalogName(String catalogName)
      Set the name of the Catalog to be searched, or null to search the default Catalog.
      Parameters:
      catalogName - The new Catalog name or null

    • getName

      public String getName()
      Return the name of the Command that we will look up and delegate execution to.
      Returns:
      The name of the Command.

    • setName

      public void setName(String name)
      Set the name of the Command that we will look up and delegate execution to.
      Parameters:
      name - The new command name

    • getNameKey

      public String getNameKey()
      Return the context attribute key under which the Command name is stored.
      Returns:
      The context key of the Command.

    • setNameKey

      public void setNameKey(String nameKey)
      Set the context attribute key under which the Command name is stored.
      Parameters:
      nameKey - The new context attribute key

    • isOptional

      public boolean isOptional()
      Return true if locating the specified command is optional.
      Returns:
      true if the Command is optional.

    • setOptional

      public void setOptional(boolean optional)
      Set the optional flag for finding the specified command.
      Parameters:
      optional - The new optional flag

    • isIgnoreExecuteResult

      public boolean isIgnoreExecuteResult()
      Return true if this command should ignore the return value from executing the looked-up command. Defaults to false, which means that the return result of executing this lookup will be whatever is returned from that command.
      Returns:
      true if result of the looked up Command should be ignored.
      Since:
      Chain 1.1

    • setIgnoreExecuteResult

      public void setIgnoreExecuteResult(boolean ignoreReturn)
      Set the rules for whether or not this class will ignore or pass through the value returned from executing the looked up command.

      If you are looking up a chain which may be "aborted" and you do not want this class to stop chain processing, then this value should be set to true.

      Parameters:
      ignoreReturn - true if result of the looked up Command should be ignored.
      Since:
      Chain 1.1

    • isIgnorePostprocessResult

      public boolean isIgnorePostprocessResult()
      Return true if this command is a Filter and should ignore the return value from executing the looked-up Filter's postprocess() method.

      Defaults to false, which means that the return result of executing this lookup will be whatever is returned from that Filter.

      Returns:
      true if result of the looked up Filter's postprocess() method should be ignored.
      Since:
      Chain 1.1

    • setIgnorePostprocessResult

      public void setIgnorePostprocessResult(boolean ignorePostprocessResult)
      Set the rules for whether or not this class will ignore or pass through the value returned from executing the looked up Filter's postprocess() method.

      If you are looking up a Filter which may be "aborted" and you do not want this class to stop chain processing, then this value should be set to true.

      Parameters:
      ignorePostprocessResult - true if result of the looked up Filter's postprocess() method should be ignored.
      Since:
      Chain 1.1

    • execute

      public boolean execute(C context) throws Exception
      Look up the specified command, and (if found) execute it. Unless ignoreExecuteResult is set to true, return the result of executing the found command. If no command is found, return false, unless the optional property is false, in which case an IllegalArgumentException will be thrown.
      Specified by:
      execute in interface Command<C extends Context>
      Parameters:
      context - The context for this request
      Returns:
      the result of executing the looked-up command, or false if no command is found or if the command is found but the ignoreExecuteResult property of this instance is true
      Throws:
      IllegalArgumentException - if no such Command can be found and the optional property is set to false
      Exception - if and error occurs in the looked-up Command.

    • postprocess

      public boolean postprocess(C context, Exception exception)
      If the executed command was itself a Filter, call the postprocess() method of that Filter as well.
      Specified by:
      postprocess in interface Filter<C extends Context>
      Parameters:
      context - The context for this request
      exception - Any Exception thrown by command execution
      Returns:
      the result of executing the postprocess method of the looked-up command, unless ignorePostprocessResult is true. If no command is found, return false, unless the optional property is false, in which case IllegalArgumentException will be thrown.

    • getCatalog

      protected Catalog<C> getCatalog(C context)
      Return the Catalog to look up the Command in.
      Parameters:
      context - Context for this request
      Returns:
      The catalog.
      Throws:
      IllegalArgumentException - if no Catalog can be found
      Since:
      Chain 1.2

    • getCommand

      protected Command<C> getCommand(C context)
      Return the Command instance to be delegated to.
      Parameters:
      context - Context for this request
      Returns:
      The looked-up Command.
      Throws:
      IllegalArgumentException - if no such Command can be found and the optional property is set to false

    • getCommandName

      protected String getCommandName(C context)
      Return the name of the Command instance to be delegated to.
      Parameters:
      context - Context for this request
      Returns:
      The name of the Command instance
      Since:
      Chain 1.2