Make cauldron contents more clearly hashable

In theory, any interface implementation with the same two values will hash to the same location. Means I do not need to use a pair for map lookups, cauldron contents is sufficient

src/main/java/knightminer/inspirations/library/recipe/cauldron/contents/EmptyCauldronContents.java

@@ -31,4 +31,9 @@ public ResourceLocation getTextureName() {
   public int getTintColor() {
     return -1;
   }
+
+  @Override
+  public <T> boolean matches(CauldronContentType<T> type, T value) {
+    return type == CauldronContentTypes.EMPTY;
+  }
 }

src/main/java/knightminer/inspirations/library/recipe/cauldron/contents/ICauldronContents.java

@@ -37,4 +37,34 @@ public interface ICauldronContents {
    * @return  Tint color
    */
   int getTintColor();
+
+
+  /* Mapping */
+
+  /**
+   * Checks if these cauldron contents match the given arguments. Use this for {@link #equals(Object)} implementations
+   * @param type   Content type
+   * @param value  Value of the content
+   * @param <T>  Content class
+   * @return True if they match
+   */
+  <T> boolean matches(CauldronContentType<T> type, T value);
+
+  /**
+   * For consistency, hash code should be {@code 31 * type.hashCode() + value.hashCode()}
+   * @return  Hash code for the given type and value
+   */
+  @Override
+  int hashCode();
+
+  /**
+   * Checks if the contents contain the given value. Unlike {@link #matches(CauldronContentType, Object)}, supports overrides.
+   * @param type   Content type
+   * @param value  Value of the content
+   * @param <T>  Content class
+   * @return  True if get would return this value
+   */
+  default <T> boolean contains(CauldronContentType<T> type, T value) {
+    return get(type).map(value::equals).orElse(false);
+  }
 }

src/main/java/knightminer/inspirations/recipes/recipe/cauldron/contents/CauldronContents.java

@@ -48,16 +48,21 @@ public int getTintColor() {
     return type.getColor(value);
   }
 
+  @Override
+  public <T> boolean matches(CauldronContentType<T> type, T value) {
+    return this.type == type && this.value == value;
+  }
+
   @Override
   public boolean equals(Object other) {
     if (this == other) {
       return true;
     }
-    if (!(other instanceof CauldronContents)) {
+    if (!(other instanceof ICauldronContents)) {
       return false;
     }
-    CauldronContents<?> contents = (CauldronContents<?>)other;
-    return this.type == contents.type && this.value.equals(contents.value);
+    ICauldronContents contents = (ICauldronContents)other;
+    return contents.matches(type, value);
   }
 
   @Override