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.



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# File 'lib/omf-web/data_source_proxy.rb', line 158

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

Instance Attribute Details

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/omf-web/data_source_proxy.rb', line 100

def name
  @name
end

Class Method Details

.[](name) ⇒ Object 



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# File 'lib/omf-web/data_source_proxy.rb', line 35

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.



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# File 'lib/omf-web/data_source_proxy.rb', line 55

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
    # 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
    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
      
    # n_name = "#{ds_name}_nodes".to_sym
    # l_name = "#{ds_name}_links".to_sym
    # if (nodes = OMF::Web::SessionStore[n_name, :dsp])
      # # assume links exist as well
      # links = OMF::Web::SessionStore[l_name, :dsp]                
    # else
      # nodes = OMF::Web::SessionStore[n_name, :dsp] = self.new(n_name, ds[:nodes])
      # links = OMF::Web::SessionStore[l_name, :dsp] = self.new(l_name, ds[:links])
    # end
    # return [nodes, links]
  end
  
  proxy = OMF::Web::SessionStore[ds_name, :dsp] ||= self.new(ds_name, ds)
  return [proxy]
end

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

Register a data source.

params data_source - Data source to register params opts:

name - Name to use instead of data source's native name



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# File 'lib/omf-web/data_source_proxy.rb', line 22

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
    dsh = data_source.to_tables(opts)
    @@datasources[name] = dsh
  else
    @@datasources[name] = data_source
  end
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



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# File 'lib/omf-web/data_source_proxy.rb', line 131

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



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# File 'lib/omf-web/data_source_proxy.rb', line 117

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 rows, ds.offset
  end
  @data_source.on_row_added(block.object_id) do |row, offset|
    debug "on_changed: more data: #{row.inspect}"
    block.call [row], offset
  end
end

#on_update(req) ⇒ Object 



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# File 'lib/omf-web/data_source_proxy.rb', line 106

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

#reset ⇒ Object 



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# File 'lib/omf-web/data_source_proxy.rb', line 102

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

#to_javascript(opts = {}) ⇒ Object 



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# File 'lib/omf-web/data_source_proxy.rb', line 138

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