Class DS_TABLE PreviousNext

note
description:

    "Data structures whose items are accessible through keys"

library:    "Gobo Eiffel Structure Library"
author:     "Eric Bezault <ericb@gobosoft.com>"
copyright:  "Copyright (c) 2000-2001, Eric Bezault and others"
license:    "MIT License"
deferred class interface
DS_TABLE [G, K]
inherit
DS_CONTAINER [G]
feature {NONE} -- Initialization
make_default
        -- Create an empty container.
        -- (From DS_CONTAINER.)
    deferred
    ensure
        empty: is_empty
feature -- Access
infix "@", item (k: K): G
        -- Item associated with k
    require
        has_k: has (k)
    deferred
feature -- Measurement
count: INTEGER
        -- Number of items in container
        -- (From DS_CONTAINER.)
    deferred
feature -- Status report
is_empty: BOOLEAN
        -- Is container empty?
        -- (From DS_CONTAINER.)
valid_key (k: K): BOOLEAN
        -- Is k a valid key?
    deferred
has (k: K): BOOLEAN
        -- Is there an item associated with k?
    deferred
    ensure
        valid_key: Result implies valid_key (k)
feature -- Comparison
is_equal (other: like Current): BOOLEAN
        -- Is current container equal to other?
        -- (From GENERAL.)
    require
        other_not_void: other /= Void
    deferred
    ensure
        consistent: standard_is_equal (other) implies Result
        same_type: Result implies same_type (other)
        symmetric: Result implies other.is_equal (Current)
        same_count: Result implies count = other.count
feature -- Duplication
copy (other: like Current)
        -- Copy other to current container.
        -- (From GENERAL.)
    require
        other_not_void: other /= Void
        type_identity: same_type (other)
    deferred
    ensure
        is_equal: is_equal (other)
feature -- Element change
replace (v: G; k: K)
        -- Replace item associated with k by v.
    require
        has_k: has (k)
    deferred
    ensure
        replaced: item (k) = v
        same_count: count = old count
put (v: G; k: K)
        -- Associate v with key k.
    require
        valid_key: valid_key (k)
    deferred
    ensure
        inserted: has (k) and then item (k) = v
        same_count: (old has (k)) implies (count = old count)
        one_more: (not old has (k)) implies (count = old count + 1)
put_new (v: G; k: K)
        -- Associate v with key k.
    require
        valid_key: valid_key (k)
        new_item: not has (k)
    deferred
    ensure
        one_more: count = old count + 1
        inserted: has (k) and then item (k) = v
swap (k, l: K)
        -- Exchange items associated with k and l.
    require
        valid_k: has (k)
        valid_l: has (l)
    ensure
        same_count: count = old count
        new_k: item (k) = old item (l)
        new_l: item (l) = old item (k)
feature -- Removal
remove (k: K)
        -- Remove item associated with k.
    require
        valid_key: valid_key (k)
    deferred
    ensure
        same_count: (not old has (k)) implies (count = old count)
        one_less: (old has (k)) implies (count = old count - 1)
        removed: not has (k)
wipe_out
        -- Remove all items from container.
        -- (From DS_CONTAINER.)
    deferred
    ensure
        wiped_out: is_empty
invariant
positive_count: count >= 0
empty_definition: is_empty = (count = 0)
    -- (From DS_CONTAINER.)
end -- class DS_TABLE

Copyright 2000-2001, Eric Bezault
mailto:
ericb@gobosoft.com
http:
//www.gobosoft.com
Last Updated: 31 March 2001

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