reduce pipeline boilerplate

common/src/main/java/com/dfsek/terra/biome/StandardBiomeProvider.java

@@ -76,7 +76,7 @@ public class StandardBiomeProvider implements BiomeProvider {
             this.resolution = resolution;
         }
 
-        public void setBuilder(NoiseBuilder builder) {
+        public void setBlender(NoiseBuilder builder) {
             this.builder = builder;
         }
 

common/src/main/java/com/dfsek/terra/biome/pipeline/mutator/BorderListMutator.java

@@ -0,0 +1,46 @@
+package com.dfsek.terra.biome.pipeline.mutator;
+
+import com.dfsek.terra.api.math.ProbabilityCollection;
+import com.dfsek.terra.api.math.noise.samplers.NoiseSampler;
+import com.dfsek.terra.api.world.biome.TerraBiome;
+
+import java.util.Map;
+
+public class BorderListMutator implements BiomeMutator {
+    private final String border;
+    private final NoiseSampler noiseSampler;
+    private final ProbabilityCollection<TerraBiome> replaceDefault;
+    private final String defaultReplace;
+    private final Map<TerraBiome, ProbabilityCollection<TerraBiome>> replace;
+
+    public BorderListMutator(Map<TerraBiome, ProbabilityCollection<TerraBiome>> replace, String border, String defaultReplace, NoiseSampler noiseSampler, ProbabilityCollection<TerraBiome> replaceDefault) {
+        this.border = border;
+        this.noiseSampler = noiseSampler;
+        this.replaceDefault = replaceDefault;
+        this.defaultReplace = defaultReplace;
+        this.replace = replace;
+    }
+
+    @Override
+    public TerraBiome mutate(ViewPoint viewPoint, double x, double z) {
+        TerraBiome origin = viewPoint.getBiome(0, 0);
+        if(origin.getTags().contains(defaultReplace)) {
+            for(int xi = -1; xi <= 1; xi++) {
+                for(int zi = -1; zi <= 1; zi++) {
+                    if(xi == 0 && zi == 0) continue;
+                    TerraBiome current = viewPoint.getBiome(xi, zi);
+                    if(current == null) continue;
+                    if(current.getTags().contains(border)) {
+                        if(replace.containsKey(origin)) {
+                            TerraBiome biome = replace.get(origin).get(noiseSampler, x, z);
+                            return biome == null ? origin : biome;
+                        }
+                        TerraBiome biome = replaceDefault.get(noiseSampler, x, z);
+                        return biome == null ? origin : biome;
+                    }
+                }
+            }
+        }
+        return origin;
+    }
+}

common/src/main/java/com/dfsek/terra/biome/pipeline/mutator/BorderMutator.java

@@ -26,7 +26,10 @@ public class BorderMutator implements BiomeMutator {
                     if(xi == 0 && zi == 0) continue;
                     TerraBiome current = viewPoint.getBiome(xi, zi);
                     if(current == null) continue;
-                    if(current.getTags().contains(border)) return replace.get(noiseSampler, x, z);
+                    if(current.getTags().contains(border)) {
+                        TerraBiome biome = replace.get(noiseSampler, x, z);
+                        return biome == null ? origin : biome;
+                    }
                 }
             }
         }

common/src/main/java/com/dfsek/terra/biome/pipeline/mutator/ReplaceListMutator.java

@@ -0,0 +1,35 @@
+package com.dfsek.terra.biome.pipeline.mutator;
+
+import com.dfsek.terra.api.math.ProbabilityCollection;
+import com.dfsek.terra.api.math.noise.samplers.NoiseSampler;
+import com.dfsek.terra.api.world.biome.TerraBiome;
+
+import java.util.Map;
+
+public class ReplaceListMutator implements BiomeMutator {
+    private final Map<TerraBiome, ProbabilityCollection<TerraBiome>> replace;
+    private final NoiseSampler sampler;
+    private final ProbabilityCollection<TerraBiome> replaceDefault;
+    private final String defaultTag;
+
+    public ReplaceListMutator(Map<TerraBiome, ProbabilityCollection<TerraBiome>> replace, String defaultTag, ProbabilityCollection<TerraBiome> replaceDefault, NoiseSampler sampler) {
+        this.replace = replace;
+        this.sampler = sampler;
+        this.defaultTag = defaultTag;
+        this.replaceDefault = replaceDefault;
+    }
+
+    @Override
+    public TerraBiome mutate(ViewPoint viewPoint, double x, double z) {
+        TerraBiome center = viewPoint.getBiome(0, 0);
+        if(replace.containsKey(center)) {
+            TerraBiome biome = replace.get(center).get(sampler, x, z);
+            return biome == null ? viewPoint.getBiome(0, 0) : biome;
+        }
+        if(viewPoint.getBiome(0, 0).getTags().contains(defaultTag)) {
+            TerraBiome biome = replaceDefault.get(sampler, x, z);
+            return biome == null ? viewPoint.getBiome(0, 0) : biome;
+        }
+        return center;
+    }
+}