Functional Paths

Before continue

This is an advanced feature, you can ignore this because is rarely used.

To understand this page you should see Tag Objects guide.

The tree-like paths used by Rtag is quite simple, so there is a more complex way to handle edits with functions that accept NBTTagCompound and NBTTagList objects while the path is resolved.

Usage

For example, suppose we have the following data in a NBT:

main:
  list:
    - id: EPIC
      value: 40
    - id: RARE
      value: 30
    - id: LEGENDARY
      value: 50
my:
  custom:
    list:
      - 15
      - 40
      - 39
  path: "Hello"

It's impossible for a tree-like path to get the value of id EPIC, because it's on a list.

In a normal case you should get the entire list and iterate hover to check what value has EPIC in id, which is quite expensive because Rtag will convert the entire list into normal objects including unused values in the operation.

To solve that you can use functional paths by using a function that iterate hover NBTTagList directly.

// Prepare the function
ThrowableFunction<Object, Object> function = nbtList -> {
    for (Object nbtCompound : TagList.getValue(nbtList)) {
        Object id = TagCompound.get(nbtCompound, "id");
        if ("EPIC".equals(TagBase.getValue(id))) {
            return nbtCompound;
        }
    }
    return null;
};


// --- Using Rtag instance
Rtag rtag = ...;
Object compound = ...;
// Get the value path from object with EPIC id
int value = rtag.get(compound, "main", "list", function, "value");
// Or replace the value
rtag.set(compound, 45, "main", "list", function, "value");


// --- Using RtagEditor instance
RtagEditor tag = ...;
// Get the value path from object with EPIC id
int value = tag.get("main", "list", function, "value");
// Or replace the value
tag.set(45, "main", "list", function, "value");

If you want to get value from objects id RARE or LEGENDARY you can register a function provided by method.

private ThrowableFunction<Object, Object> getFunction(String type) {
    return nbtList -> {
        for (Object nbtCompound : TagList.getValue(nbtList)) {
            Object id = TagCompound.get(nbtCompound, "id");
            if (type.equals(TagBase.getValue(id))) {
                return nbtCompound;
            }
        }
        return null;
    };
}

And use like this:

// --- Using Rtag instance
Rtag rtag = ...;
Object compound = ...;
// Get the value path from object with RARE id
int value = rtag.get(compound, "main", "list", getFunction("RARE"), "value");
// Or replace the value
rtag.set(compound, 35, "main", "list", getFunction("RARE"), "value");


// --- Using RtagEditor instance
RtagEditor tag = ...;
// Get the value path from object with LEGENDARY id
int value = tag.get("main", "list", getFunction("LEGENDARY"), "value");
// Or replace the value
tag.set(55, "main", "list", getFunction("LEGENDARY"), "value");

Usage​

Usage