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 * Copyright (C) 2026, Leo Galambos
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package org.egothor.stemmer.trie;

import java.util.LinkedHashMap;
import java.util.Map;

/**
 * Mutable build-time node.
 *
 * <p>
 * The maps exposed by the accessors are the internal mutable backing state of
 * the node. They are returned directly for efficiency and are intended only for
 * closely related trie-building infrastructure.
 *
 * @param <V> value type
 */
public final class MutableNode<V> {

    /**
     * Child nodes indexed by transition character.
     */
    private final Map<Character, MutableNode<V>> children;

    /**
     * Local terminal value counts stored exactly at this node.
     */
    private final Map<V, Integer> valueCounts;

    /**
     * Creates an empty node.
     */
    public MutableNode() {
        this.children = new LinkedHashMap<>();
        this.valueCounts = new LinkedHashMap<>();
    }

    /**
     * Returns the internal child-node map indexed by transition character.
     *
     * <p>
     * The returned map is the internal mutable backing state of this node and is
     * exposed only for efficient cooperation with trie-building infrastructure.
     *
     * @return internal child-node map
     */
    public Map<Character, MutableNode<V>> children() {
        return this.children;
    }

    /**
     * Returns the internal local terminal value-count map.
     *
     * <p>
     * The returned map is the internal mutable backing state of this node and is
     * exposed only for efficient cooperation with trie-building infrastructure.
     *
     * @return internal local value-count map
     */
    public Map<V, Integer> valueCounts() {
        return this.valueCounts;
    }
}
