Package com.mckoi.database

Class StateStore

  • class StateStore
extends java.lang.Object
    A store that manages the current state of all tables in a Conglomerate. It persistantly manages three pieces of information about a conglomerate - the tables that are visible, the tables that are deleted, and a table_id value assigned to new tables that are created.

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      (package private) static class  StateStore.StateResource
      Represents a single StateResource in either a visible or delete list in this state file.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private boolean del_list_change
      Set to true if the delete list was changed.
      private long del_p
      Pointer to the delete table area in the store.
      private java.util.ArrayList delete_list
      The list of deleted state resources.
      private MutableArea header_area
      The header area of the state store.
      private int MAGIC
      The MAGIC value used for state header areas.
      private Store store
      The Store object this state store wraps around.
      private int table_id
      The current table identifier.
      private boolean vis_list_change
      Set to true if the visible list was changed.
      private long vis_p
      Pointer to the visible table area in the store.
      private java.util.ArrayList visible_list
      The list of visible state resources.

    • Constructor Summary

      Constructors 
      Constructor Description
      StateStore​(Store store)
      Constructs the StateStore.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void addDeleteResource​(StateStore.StateResource resource)
      Adds the given StateResource to the deleted table list.
      void addVisibleResource​(StateStore.StateResource resource)
      Adds the given StateResource to the visible table list.
      boolean commit()
      Commits the current state to disk so that it makes a persistent change to the state.
      boolean containsVisibleResource​(int table_id)
      Returns true if the visible list contains a state resource with the given table id value.
      long convert​(java.io.File legacy_sf, DebugLogger debug)
      Reads a legacy state file (pre version 1) and converts it to a state store format compatible with this store.
      long create()
      Creates the state store in the store and returns a pointer to the header used later for initializing the state.
      StateStore.StateResource[] getDeleteList()
      Returns a list of all table resources that are currently in the deleted list.
      StateStore.StateResource[] getVisibleList()
      Returns a list of all table resources that are currently in the visible list.
      void init​(long header_p)
      Initializes the state store given a pointer to the header area in the store.
      int nextTableID()
      Returns the next table id and increments the table_id counter.
      private void readStateResourceList​(java.util.ArrayList list, long pointer)
      Reads the state resource list from the given area in the store.
      void removeDeleteResource​(java.lang.String name)
      Removes the resource with the given name from the deleted list.
      private void removeResource​(java.util.ArrayList list, java.lang.String name)
      Removes the given resource from the list.
      void removeVisibleResource​(java.lang.String name)
      Removes the resource with the given name from the visible list.
      private long writeListToStore​(java.util.ArrayList list)
      Writes the given list to the store and returns a pointer to the area once the write has finished.
      private void writeStateResourceList​(java.util.ArrayList list, java.io.DataOutputStream d_out)
      Writes the state resource list to the given area in the store.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • MAGIC

        private int MAGIC
        The MAGIC value used for state header areas.

      • store

        private Store store
        The Store object this state store wraps around.

      • table_id

        private int table_id
        The current table identifier.

      • header_area

        private MutableArea header_area
        The header area of the state store. The format of the header area is; MAGIC(4) - RESERVED(4) - TABLE_ID(8) - VISIBLE_TABLES_POINTER(8) - DELETED_TABLES_POINTER(8)

      • vis_p

        private long vis_p
        Pointer to the visible table area in the store.

      • del_p

        private long del_p
        Pointer to the delete table area in the store.

      • visible_list

        private java.util.ArrayList visible_list
        The list of visible state resources.

      • delete_list

        private java.util.ArrayList delete_list
        The list of deleted state resources.

      • vis_list_change

        private boolean vis_list_change
        Set to true if the visible list was changed.

      • del_list_change

        private boolean del_list_change
        Set to true if the delete list was changed.

    • Constructor Detail

      • StateStore

        public StateStore​(Store store)
        Constructs the StateStore.

    • Method Detail

      • removeResource

        private void removeResource​(java.util.ArrayList list,
                            java.lang.String name)
        Removes the given resource from the list.

      • readStateResourceList

        private void readStateResourceList​(java.util.ArrayList list,
                                   long pointer)
                            throws java.io.IOException
        Reads the state resource list from the given area in the store.
        Throws:
        java.io.IOException

      • writeStateResourceList

        private void writeStateResourceList​(java.util.ArrayList list,
                                    java.io.DataOutputStream d_out)
                             throws java.io.IOException
        Writes the state resource list to the given area in the store.
        Throws:
        java.io.IOException

      • writeListToStore

        private long writeListToStore​(java.util.ArrayList list)
                       throws java.io.IOException
        Writes the given list to the store and returns a pointer to the area once the write has finished.
        Throws:
        java.io.IOException

      • create

        public long create()
            throws java.io.IOException
        Creates the state store in the store and returns a pointer to the header used later for initializing the state.
        Throws:
        java.io.IOException

      • init

        public void init​(long header_p)
          throws java.io.IOException
        Initializes the state store given a pointer to the header area in the store.
        Throws:
        java.io.IOException

      • convert

        public long convert​(java.io.File legacy_sf,
                    DebugLogger debug)
             throws java.io.IOException
        Reads a legacy state file (pre version 1) and converts it to a state store format compatible with this store. Fortunately the conversion is fairly straight-forward. This is otherwise the same as using the 'create' method.
        Throws:
        java.io.IOException

      • nextTableID

        public int nextTableID()
                throws java.io.IOException
        Returns the next table id and increments the table_id counter.
        Throws:
        java.io.IOException

      • getVisibleList

        public StateStore.StateResource[] getVisibleList()
        Returns a list of all table resources that are currently in the visible list.

      • getDeleteList

        public StateStore.StateResource[] getDeleteList()
        Returns a list of all table resources that are currently in the deleted list.

      • containsVisibleResource

        public boolean containsVisibleResource​(int table_id)
        Returns true if the visible list contains a state resource with the given table id value.

      • addVisibleResource

        public void addVisibleResource​(StateStore.StateResource resource)
        Adds the given StateResource to the visible table list. This does not persist the state. To persist this change a call to 'commit' must be called.

      • addDeleteResource

        public void addDeleteResource​(StateStore.StateResource resource)
        Adds the given StateResource to the deleted table list. This does not persist the state. To persist this change a call to 'commit' must be called.

      • removeVisibleResource

        public void removeVisibleResource​(java.lang.String name)
        Removes the resource with the given name from the visible list. This does not persist the state. To persist this change a call to 'commit' must be called.

      • removeDeleteResource

        public void removeDeleteResource​(java.lang.String name)
        Removes the resource with the given name from the deleted list. This does not persist the state. To persist this change a call to 'commit' must be called.

      • commit

        public boolean commit()
               throws java.io.IOException
        Commits the current state to disk so that it makes a persistent change to the state. A further call to 'synch()' will synchronize the file. This will only commit changes if there were modifications to the state. Returns true if this commit caused any changes to the persistant state.
        Throws:
        java.io.IOException