webadmin: Remove StringHelper.stringEqulas calls

Replaced StringHelper.stringEquals calls with a good old fashioned
equals when one of the arguments is a hardcoded string literal or a
constant, so a double null check is not required.

This patch several objectives:
1. The code is cleaner and easier to read
2. A slight performance improvement
3. It's a stepping stone towards removing StringHelper altogether

Change-Id: Ida454afa0308889d56ae078a858a0fc5e5254845
Signed-off-by: Allon Mureinik <amureini@redhat.com>
webadmin: CustomPropertyValidation blank string

Fixed up the way a blank string is tested.
Before this patch, it's trim()ed and compared to "" using
StringHelper.stringEquals. Since trim() is called on this string, we can
assume it's not null, so StringHelper.stringEquals is redundant. Since
we know we have a non-null instance, we can simply used the optimized
isEmpty().

An additional advantage is removing another call to
StringHelper.stringsEqual, moving one step closer to eliminating this
method.

Change-Id: I3592a500d5af41593a3f8f9eb1e888d6ac22cf04
Signed-off-by: Allon Mureinik <amureini@redhat.com>
webadmin: RunOnceModel empty string validation

Replaced the test for domain's emptiness from
StringHelper.stringsEquals(selectedDomain, "") to a simpler
StringHelper.isNullOrEmpty(selectedDomain). Note that although there is
a slight difference in semantics, there is no point in having a null
selectedDomain, and it's implicitly assumed to be not-null in other
places of the code.

Change-Id: I101f3d24a1bf7dd74b73931258e4dee101931618
Signed-off-by: Allon Mureinik <amureini@redhat.com>
webadmin: VmGeneralModel empty string validation

Replaced the test for domain's emptiness from
StringHelper.stringsEquals(vm.getCustomProperties(), "") to a simpler
StringHelper.isNullOrEmpty(vm.getCustomProperties()). Note that
although there is a slight difference in semantics, there is no
point in having null custom properties, and it's implicitly assumed
to be not-null in other places of the code.

Change-Id: Ib45cf6fb428cd6750a1264ca45a8b332420bc57f
Signed-off-by: Allon Mureinik <amureini@redhat.com>
core,webadmin: Remove StringHelper.stringsEquals

Removed the String specific StringHelper.strinsEqual and replaced all
the calls with the general purpose ObjectUtils.objectsEqual, which
has exactly the same functionality.

Change-Id: Iaef58d6d0602b93cb6fc5085466e116949549170
Signed-off-by: Allon Mureinik <amureini@redhat.com>
engine: Remove javadoc from one of DiskValidator APIs

Removed javadoc is not alligned with the curent API signature and
doesn't provide any additional information about it.

Change-Id: Iaa3d1173400be9eae7f0ba79344fdeb9724ca6d3
Signed-off-by: Sergey Gotliv <sgotliv@redhat.com>