Class: OMF::Web::DataSourceProxy

Inherits:
Common::LObject show all
Defined in:
lib/omf-web/data_source_proxy.rb

Overview

This object maintains synchronization between a JS DataSource object in a web browser and the corresponding OmlTable in this server.

Constant Summary collapse

@@datasources = 
{}

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Common::Loggable

#_logger, #debug, #error, #fatal, #info, init_log, logger, set_environment, #warn

Constructor Details

#initialize(name, data_source) ⇒ DataSourceProxy

Returns a new instance of DataSourceProxy.



172
173
174
175
 
# File 'lib/omf-web/data_source_proxy.rb', line 172

def initialize(name, data_source)
  @name = name
  @data_source = data_source
end

Instance Attribute Details

#name ⇒ Object (readonly)

Returns the value of attribute name.



112
113
114
 
# File 'lib/omf-web/data_source_proxy.rb', line 112

def name
  @name
end

Class Method Details

.[](name) ⇒ Object 



48
49
50
51
52
53
54
55
56
57
58
 
# File 'lib/omf-web/data_source_proxy.rb', line 48

def self.[](name)
  name = name.to_sym
  unless dsp = OMF::Web::SessionStore[name, :dsp]
    if ds = @@datasources[name]
      dsp = OMF::Web::SessionStore[name, :dsp] = self.new(name, ds)
    else
      warn "Requesting unknown datasource '#{name}', only know about '#{@@datasources.keys.join(', ')}'."
    end
  end
  dsp
end

.for_source(ds_descr) ⇒ Object

Return proxies for ‘ds_name’. Note, there can be more then one proxy be needed for a datasource, such as a network which has one ds for the nodes and one for the links

@return: Array of proxies

TODO: This seems to hardcode networks.



68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
 
# File 'lib/omf-web/data_source_proxy.rb', line 68

def self.for_source(ds_descr)
  #raise "FOO #{ds_descr.inspect}"
  unless ds_descr.is_a? Hash
    raise "Expected Hash, but got '#{ds_descr.class}::#{ds_descr.inspect}'"
  end
  unless ds_name = ds_descr[:name]
    raise "Missing 'name' attribute in datasource description. (#{ds_descr.inspect})"
  end
  ds_name = ds_name.to_sym
  ds = @@datasources[ds_name]
  unless ds
    top = "#{ds_name}/"
    names = @@datasources.keys.find_all { |ds_name| ds_name.to_s.start_with? top }
    unless names.empty?
      return names.map do |ds_name|
        OMF::Web::SessionStore[ds_name, :dsp] ||= self.new(ds_name, @@datasources[ds_name])
      end
    end
    # debug ">>>> #{dsa}"
    # # let's check for sub table, such as network/nodes
    # main, sub = ds_descr[:name].split('/')
    # if (sub)
      # if ds_top = @@datasources[main.to_sym]
        # ds = ds_top[sub.to_sym]
      # end
    # end
    unless ds
      raise "Unknown data source '#{ds_name}' (#{@@datasources.keys.inspect})"
    end
  end
  if ds.is_a? Hash
    raise "Is this actually used anywhere?"
    proxies = ds.map do |name, ds|
      id = "#{ds_name}_#{name}".to_sym
      proxy = OMF::Web::SessionStore[id, :dsp] ||= self.new(id, ds)
    end
    return proxies
  end

  #debug ">>>>> DS: #{ds_descr.inspect} - #{ds}"
  proxy = OMF::Web::SessionStore[ds_name, :dsp] ||= self.new(ds_name, ds)
  return [proxy]
end

.register_datasource(data_source, opts = {}) ⇒ Object

A data_source needs to support eh following methods:

* rows Returns an array of rows
* on_content_changed(lambda{action, rows}) Call provided block with actions :added, :removed
* create_sliced_table (optional)
* release Not exactly sure when that is being used
* schema Schema of row
* offset



32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
 
# File 'lib/omf-web/data_source_proxy.rb', line 32

def self.register_datasource(data_source, opts = {})
  name = (opts[:name] || data_source.name).to_sym
  if (@@datasources.key? name)
    raise "Repeated try to register data source '#{name}'"
  end
  if data_source.is_a? OMF::OML::OmlNetwork
    raise "Register link and node table separately "
  end
    # dsh = data_source.to_tables(opts)
    # @@datasources[name] = dsh
  # else
    # @@datasources[name] = data_source
  # end
  @@datasources[name] = data_source
end

Instance Method Details

#create_slice(col_name, col_value) ⇒ Object

Create a new data source which only contains a slice of the underlying data source



143
144
145
146
147
148
 
# File 'lib/omf-web/data_source_proxy.rb', line 143

def create_slice(col_name, col_value)
  ds = @data_source.create_sliced_table(col_name, col_value)
  dsp = self.class.new(ds.name, ds)
  def dsp.release; @data_source.release end
  dsp
end

#on_changed(offset, &block) ⇒ Object

Register callback to be informed of changes to the underlying data source. Call block when new rows are becoming available. Block needs ot return true if it wants to continue receiving updates.

offset: Number of records already downloaded



129
130
131
132
133
134
135
136
137
138
139
140
 
# File 'lib/omf-web/data_source_proxy.rb', line 129

def on_changed(offset, &block)
  ds = @data_source
  rows = ds.rows[(offset - ds.offset) .. -1]
  if rows && rows.length > 0
    debug "on_changed: sending #{rows.length}"
    block.call :added, rows
  end
  @data_source.on_content_changed(block.object_id) do |action, rows|
    #debug "on_changed: #{action}: #{rows.inspect}"
    block.call action, rows
  end
end

#on_update(req) ⇒ Object 



118
119
120
121
 
# File 'lib/omf-web/data_source_proxy.rb', line 118

def on_update(req)
  res = {:events => @data_source.rows}
  [res.to_json, "text/json"]
end

#reset ⇒ Object 



114
115
116
 
# File 'lib/omf-web/data_source_proxy.rb', line 114

def reset()
  # TODO: Figure out partial sending
end

#to_javascript(opts = {}) ⇒ Object 



150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
 
# File 'lib/omf-web/data_source_proxy.rb', line 150

def to_javascript(opts = {})
  #puts "to_java>>>>> #{opts.inspect}"
  sid = Thread.current["sessionID"]
  opts = opts.dup
  opts[:name] = @name
  opts[:schema] = @data_source.schema.describe
  opts[:update_url] = "/_update/#{@name}?sid=#{sid}"
  opts[:sid] = sid
  #opts[:is_static] = (@data_source.respond_to? :static?) ? @data_source.static? : false
  unless opts[:slice] # don't send any data if this is a sliced one
    #opts[:rows] = @data_source.rows[0 .. 20]
    opts[:rows] = []
    opts[:offset] = @data_source.offset
  end
  #puts "to_java2>>>>> #{opts.inspect}"

  %{
    OML.data_sources.register(#{opts.to_json});
  }

end