Harmonize resource collectors.

Change-Id: I51fdf9cdf57d3146bd9401ff67e13063830519e4

@@ -45,9 +45,7 @@ import org.slf4j.LoggerFactory;
 import java.util.Collections;
 import java.util.List;
 import java.util.SortedSet;
-import java.util.TreeSet;
 import java.util.concurrent.ExecutorService;
-import java.util.function.Supplier;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
@@ -206,10 +204,9 @@ final class ResourceDeviceListener implements DeviceListener {
             }
             LambdaQuery query = handler.behaviour(LambdaQuery.class);
             if (query != null) {
-                Supplier<SortedSet<OchSignal>> supplier = () -> new TreeSet<>(new DefaultOchSignalComparator());
                 return query.queryLambdas(port).stream()
                         .flatMap(x -> OchSignal.toFlexGrid(x).stream())
-                        .collect(Collectors.toCollection(supplier));
+                        .collect(Collectors.toCollection(DefaultOchSignalComparator::newOchSignalTreeSet));
             } else {
                 return Collections.emptySortedSet();
             }

@@ -49,9 +49,7 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.Set;
 import java.util.SortedSet;
-import java.util.TreeSet;
 import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.function.Supplier;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
@@ -209,12 +207,11 @@ public class CalientFiberSwitchHandshaker
                 ChannelSpacing.CHL_12P5GHZ.frequency().asHz();
         long stopSpacingMultiplier = Spectrum.O_BAND_MAX.subtract(Spectrum.CENTER_FREQUENCY).asHz() /
                 ChannelSpacing.CHL_12P5GHZ.frequency().asHz();
-        Supplier<SortedSet<OchSignal>> supplier = () -> new TreeSet<>(new DefaultOchSignalComparator());
 
         // Only consider odd values for the multiplier (for easy mapping to fixed grid)
         return IntStream.rangeClosed((int) startSpacingMultiplier, (int) stopSpacingMultiplier)
                 .filter(i -> i % 2 == 1)
                 .mapToObj(i -> new OchSignal(GridType.FLEX, ChannelSpacing.CHL_6P25GHZ, i, 1))
-                .collect(Collectors.toCollection(supplier));
+                .collect(Collectors.toCollection(DefaultOchSignalComparator::newOchSignalTreeSet));
     }
 }

@@ -57,9 +57,7 @@ import java.util.LinkedList;
 import java.util.List;
 import java.util.Set;
 import java.util.SortedSet;
-import java.util.TreeSet;
 import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.function.Supplier;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
@@ -373,9 +371,8 @@ public class OfOpticalSwitchImplLinc13
         }
 
         // OMS ports expose 80 fixed grid lambdas of 50GHz width, centered around the ITU-T center frequency 193.1 THz.
-        Supplier<SortedSet<OchSignal>> supplier = () -> new TreeSet<>(new DefaultOchSignalComparator());
         return IntStream.range(0, LAMBDA_COUNT)
                 .mapToObj(x -> new OchSignal(GridType.DWDM, ChannelSpacing.CHL_50GHZ, x - (LAMBDA_COUNT / 2), 4))
-                .collect(Collectors.toCollection(supplier));
+                .collect(Collectors.toCollection(DefaultOchSignalComparator::newOchSignalTreeSet));
     }
 }