TACHYON-8 [WIP] First drop of Tachyon neo configuration

The PR includes:
-) TACHYON-193
Add new Tachyon properties file configuration.  
Add new code to support Tachyon properties configuration for runtime. 
This will be file based could be overriden via site specific configuration file or override collection in the TachyonConf class.
-) TACHYON-194
Add TachyonConf class to unify all Tachyon configurations.
Use single class TachyonConf to manage the configurations properties as key-value store.

Because the value is null. This is more inline with how java APIs work.
On Nov 14, 2014 5:29 PM, "Henry Saputra" <notifications@github.com> wrote:

> In core/src/main/java/tachyon/conf/TachyonConf.java:
>
> > +      return defaultValue;
> > +    }
> > +  }
> > +
> > +  public boolean getBoolean(String key, boolean defaultValue) {
> > +    if (mProperties.containsKey(key)) {
> > +      String rawValue = mProperties.getProperty(key);
> > +      return Boolean.getBoolean(lookup(rawValue));
> > +    } else {
> > +      return defaultValue;
> > +    }
> > +  }
> > +
> > +  public List<String> getList(String key, String delimiter, List<String> defaultValue) {
> > +    if (delimiter == null) {
> > +      throw new IllegalArgumentException("Illegal separator for Tachyon properties as list");
>
> Why NPE is better?
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/amplab/tachyon/pull/529/files#r20398104>.
>