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package org.egothor.stemmer.trie;

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

import org.egothor.stemmer.ReductionSettings;

/**
 * Reduction context used while canonicalizing mutable nodes.
 *
 * @param <V> value type
 */
public final class ReductionContext<V> {

    /**
     * Reduction settings.
     */
    private final ReductionSettings settings;

    /**
     * Canonical nodes by signature.
     */
    private final Map<ReductionSignature<V>, ReducedNode<V>> canonicalNodes;

    /**
     * Creates a new context.
     *
     * @param settings settings
     */
    public ReductionContext(final ReductionSettings settings) {
        this.settings = settings;
        this.canonicalNodes = new LinkedHashMap<>();
    }

    /**
     * Looks up a canonical node.
     *
     * @param signature signature
     * @return canonical node, or {@code null} if absent
     */
    public ReducedNode<V> lookup(final ReductionSignature<V> signature) {
        return this.canonicalNodes.get(signature);
    }

    /**
     * Registers a canonical node.
     *
     * @param signature signature
     * @param node      node
     */
    public void register(final ReductionSignature<V> signature, final ReducedNode<V> node) {
        this.canonicalNodes.put(signature, node);
    }

    /**
     * Returns the settings.
     *
     * @return settings
     */
    public ReductionSettings settings() {
        return this.settings;
    }

    /**
     * Returns the number of canonical nodes.
     *
     * @return canonical node count
     */
    public int canonicalNodeCount() {
        return this.canonicalNodes.size();
    }
}
