[SalesForce] How to pass parent component Attribute values to Child Components when Lightning Application gets loaded initially

The effective mechanism by which two components can work is by using Events .Lightning framework works on Event driven paradigm .

You will have a Publisher component that will publish event and you will have a listener that will listen to the events and handle the events .

An excellent blogs from this is below

https://developer.salesforce.com/blogs/developer-relations/2015/03/lightning-component-framework-custom-events.html

http://bobbuzzard.blogspot.com/2015/05/lightning-component-events.html

Observe how easy it is to create events for a component

 <aura:event type="APPLICATION" description="Search Event">
  <aura:attribute name="term" type="String" />
 </aura:event>

Like OOPS you can also use concept of interface and implement the interface

To use an interface, you must implement it. An interface can't be used directly in markup otherwise.

Set the implements system attribute in the aura:component tag to the name of the interface that you are implementing.

For example: aura:component implements="mynamespace:myinterface"

A component can implement an interface and extend another component. aura:component extends="ns1:cmp1" implements="ns2:intf1"

An interface can extend multiple interfaces using a comma-separated list. aura:interface extends="ns:intf1,ns:int2"

I actually found a solution (or a workaround - still don't know). I will put it here in case somebody will come across same issue.

I had to dynamically recreate child component - therefore I used ChildComponentWrapper:

How it looks right now:

ParentComponent

<aura:component controller="PrdConfigCls">
  <aura:attribute name="paramProductId" type="String"/>
  <aura:attribute name="product" type="PrdConfigCls.Product"/>
  <aura:attribute name="attributes" type="PrdConfigCls.Attribute[]"/>
  <aura:handler name="change" value="{!v.paramProductId}" action="{!c.paramProductIdChangeEventHandler}"/>

 <div aura:id="container">     
 // in this place ChildComponentWrapper will instantiate after change event (helper)
 </div>

</aura:component>

ParentComponentHelper

({
    loadProductConfiguration : function(component) {

        var action = component.get("c.getProjectProductDefinition");
        action.setParams({  "projectProductId": component.get("v.paramProductId") });
        var self = this;

        action.setCallback(this, function(a) {

            var productResp = a.getReturnValue();
            var product = JSON.parse(productResp);
            component.set("v.product", product);
            component.set("v.attributes", product.attributes);

            //console.log(component.get("v.attributes"));

            var container = component.find("container");
            $A.createComponent("c:ChildComponentWrapper",
                           {attributeParam: product.attributes},
                           function(cmp) {
                               container.set("v.body", [cmp]);
                           });

        });
        $A.enqueueAction(action);

    }
})

ChildComponentWrapper

<aura:component controller="PrdConfigCls">
  <aura:attribute name="attributeParam" type="PrdConfigCls.Attribute[]"/>

  <aura:iteration items="{!v.attributes}" var="attr">
     <c:ChildComponent attributeParam="{!attr}"/>
  </aura:iteration>
</aura:component/>