setConcurency method: it is used to dynamically change concurreny. + test cases

src/JobManager.js

@@ -30,12 +30,24 @@ function JobManager(opts){
 
 JobManager.prototype.updateState = function(){
     var workers = this.workers;
-    var tmpPoolLen = workers.length &&  (workers.length * Math.ceil( this.concurrency/workers.length ) ) , i;
+    var tmpPoolBlock = workers.length &&  Math.ceil( this.concurrency/workers.length ) , i;
     var tmpPool = [];
-    for( i=0; i < tmpPoolLen; i++){
-        tmpPool[i] = workers[ i % workers.length ];
+    for( i=0; i < tmpPoolBlock; i++){
+        tmpPool = tmpPool.concat( this.workers );
     }
     this.tmpPool = tmpPool;
+    this.tmpPoolLen = tmpPoolBlock * this.workers.length ;
+};
+
+JobManager.prototype.setConcurrency = function( newVal ){
+    if( newVal > this.tmpPoolLen ){
+        var tmpPool = this.tmpPool;
+        var additionalPoolBlocks = Math.ceil( ( newVal - this.tmpPoolLen )/this.workers.length ), i;
+        for( i=0; i < additionalPoolBlocks; i++){
+            tmpPool = tmpPool.concat( this.workers );
+        }
+        this.tmpPoolLen += additionalPoolBlocks * this.workers.length ;
+    }
 };
 
 /*

test/JobManager.spec.js

@@ -72,5 +72,20 @@ describe('JobManager', function(){
             jm.runningTasks.should.be.equal( 0 );
             done();
         });
+
+        it('should dynamically change concurrency', function( done ){
+            jm.concurrency = NO_WORKERS-1;
+            jm.updateState();
+            jm.tmpPoolLen.should.be.equal( NO_WORKERS );
+            jm.setConcurrency( (2*NO_WORKERS) +1 );
+            jm.tmpPoolLen.should.be.equal( 3*NO_WORKERS );
+            jm.setConcurrency( (3*NO_WORKERS) +1 );
+            jm.tmpPoolLen.should.be.equal( 4*NO_WORKERS );
+            jm.setConcurrency( (4*NO_WORKERS) +1 );
+            jm.tmpPoolLen.should.be.equal( 5*NO_WORKERS );
+            jm.setConcurrency( (5*NO_WORKERS) +1 );
+            jm.tmpPoolLen.should.be.equal( 6*NO_WORKERS );
+            done();
+        });
     });
 });