Initial tank layout

src/machines/java/com/enderio/machines/common/io/fluid/MachineTankLayout.java

@@ -0,0 +1,63 @@
+package com.enderio.machines.common.io.fluid;
+
+import net.minecraftforge.fluids.FluidStack;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Predicate;
+
+/**
+ * Describes the tank layout of a machine
+ */
+public class MachineTankLayout {
+
+    /**
+     * Tank configurations
+     */
+    private final List<TankConfig> tanks;
+
+    private MachineTankLayout(Builder builder) {
+        this.tanks = List.copyOf(builder.tanks);
+    }
+
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    public int getTankCount() {
+        return tanks.size();
+    }
+
+    public int getTankCapacity(int slot) {
+        return tanks.get(slot).capacity();
+    }
+
+    public boolean canInsert(int slot) {
+        return tanks.get(slot).insert();
+    }
+
+    public boolean canExtract(int slot) {
+        return tanks.get(slot).extract();
+    }
+
+    public boolean isFluidValid(int slot, FluidStack stack) {
+        return tanks.get(slot).filter().test(stack);
+    }
+
+    public static class Builder {
+        private final ArrayList<TankConfig> tanks = new ArrayList<>();
+
+        public Builder tank(TankAccess access, int capacity, boolean canInsert, boolean canRemove, Predicate<FluidStack> filter) {
+            tanks.add(new TankConfig(capacity, canInsert, canRemove, filter));
+            access.init(tanks.size() - 1);
+            return this;
+        }
+
+        public MachineTankLayout build() {
+            return new MachineTankLayout(this);
+        }
+    }
+
+    private record TankConfig(int capacity, boolean insert, boolean extract, Predicate<FluidStack> filter) {}
+
+}

src/machines/java/com/enderio/machines/common/io/fluid/TankAccess.java

@@ -0,0 +1,14 @@
+package com.enderio.machines.common.io.fluid;
+
+public class TankAccess {
+
+    private int index = Integer.MIN_VALUE;
+
+    void init(int i) {
+        if (index == Integer.MIN_VALUE) {
+            index = i;
+        } else if (index != i) {
+            throw new IllegalArgumentException("TankLayout changed dynamically from " + index + " to " + i + ", don't do that");
+        }
+    }
+}