MutableNode.java

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/*******************************************************************************
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 * Copyright (C) 2026, Leo Galambos
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions are met:
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 *
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 * 1. Redistributions of source code must retain the above copyright notice,
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 *    this list of conditions and the following disclaimer.
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 *
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 * 2. Redistributions in binary form must reproduce the above copyright notice,
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 *    this list of conditions and the following disclaimer in the documentation
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 *    and/or other materials provided with the distribution.
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 *
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 * 3. Neither the name of the copyright holder nor the names of its contributors
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 *    may be used to endorse or promote products derived from this software
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 *    without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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 * POSSIBILITY OF SUCH DAMAGE.
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 ******************************************************************************/
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package org.egothor.stemmer.trie;
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import java.util.LinkedHashMap;
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import java.util.Map;
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/**
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 * Mutable build-time node.
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 *
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 * <p>
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 * The maps exposed by the accessors are the internal mutable backing state of
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 * the node. They are returned directly for efficiency and are intended only for
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 * closely related trie-building infrastructure.
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 * </p>
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 *
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 * <p>
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 * Instances are mutable and not thread-safe. The owning builder is responsible
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 * for confinement and for ensuring that the exposed maps are not retained after
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 * compilation.
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 * </p>
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 *
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 * @param <V> value type
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 */
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public final class MutableNode<V> {
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    /**
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     * Child nodes indexed by transition character.
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     */
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    private final Map<Character, MutableNode<V>> children;
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    /**
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     * Local terminal value counts stored exactly at this node.
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     */
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    private final Map<V, Integer> valueCounts;
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    /**
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     * Whether this node was a contracted accepting leaf in a source compiled
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     * trie. Set only when a builder is reconstructed from a compiled trie (see
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     * {@code FrequencyTrieBuilders.copyOf}); it is preserved through reduction so
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     * the "accepts remaining input" generalization survives a round-trip even
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     * when the original member paths were contracted away and cannot be replayed.
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     */
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    private boolean acceptsRemainingInput;
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    /**
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     * Creates an empty node.
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     */
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    public MutableNode() {
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        this.children = new LinkedHashMap<>();
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        this.valueCounts = new LinkedHashMap<>();
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    }
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    /**
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     * Returns whether this node is marked as accepting remaining input.
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     *
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     * @return {@code true} when this node accepts any remaining lookup input
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     */
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    public boolean acceptsRemainingInput() {
88 2 1. acceptsRemainingInput : replaced boolean return with true for org/egothor/stemmer/trie/MutableNode::acceptsRemainingInput → KILLED
2. acceptsRemainingInput : replaced boolean return with false for org/egothor/stemmer/trie/MutableNode::acceptsRemainingInput → KILLED
 
        return this.acceptsRemainingInput;
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    }
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    /**
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     * Marks this node as accepting remaining input.
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     */
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    public void markAcceptsRemainingInput() {
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        this.acceptsRemainingInput = true;
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    }
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    /**
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     * Clears the accepting-remaining-input marker.
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     *
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     * <p>
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     * This transition is required when the last local value is removed: an
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     * accepting node without a value cannot resolve a lookup and is rejected by
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     * the compiled-node invariant.
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     * </p>
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     */
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    public void clearAcceptsRemainingInput() {
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        this.acceptsRemainingInput = false;
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    }
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    /**
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     * Returns the internal child-node map indexed by transition character.
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     *
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     * <p>
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     * The returned map is the internal mutable backing state of this node and is
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     * exposed only for efficient cooperation with trie-building infrastructure.
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     *
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     * @return internal child-node map
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     */
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    public Map<Character, MutableNode<V>> children() {
121 1 1. children : replaced return value with Collections.emptyMap for org/egothor/stemmer/trie/MutableNode::children → KILLED
 
        return this.children;
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    }
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    /**
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     * Returns the internal local terminal value-count map.
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     *
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     * <p>
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     * The returned map is the internal mutable backing state of this node and is
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     * exposed only for efficient cooperation with trie-building infrastructure.
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     *
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     * @return internal local value-count map
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     */
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    public Map<V, Integer> valueCounts() {
134 1 1. valueCounts : replaced return value with Collections.emptyMap for org/egothor/stemmer/trie/MutableNode::valueCounts → KILLED
 
        return this.valueCounts;
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    }
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}

Mutations

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1.1
Location : acceptsRemainingInput
Killed by : org.egothor.stemmer.FrequencyTrieTest.[engine:junit-jupiter]/[class:org.egothor.stemmer.FrequencyTrieTest]/[method:trieRejectsNullLookupKeys()] replaced boolean return with true for org/egothor/stemmer/trie/MutableNode::acceptsRemainingInput → KILLED

2.2
Location : acceptsRemainingInput
Killed by : org.egothor.stemmer.FrequencyTrieBuildersTest.[engine:junit-jupiter]/[class:org.egothor.stemmer.FrequencyTrieBuildersTest]/[method:shouldRemoveContractedAcceptingGeneralization()] replaced boolean return with false for org/egothor/stemmer/trie/MutableNode::acceptsRemainingInput → KILLED

121

1.1
Location : children
Killed by : org.egothor.stemmer.trie.MutableNodeTest.[engine:junit-jupiter]/[class:org.egothor.stemmer.trie.MutableNodeTest]/[method:shouldExposeMutableBackingChildrenMap()] replaced return value with Collections.emptyMap for org/egothor/stemmer/trie/MutableNode::children → KILLED

134

1.1
Location : valueCounts
Killed by : org.egothor.stemmer.trie.MutableNodeTest.[engine:junit-jupiter]/[class:org.egothor.stemmer.trie.MutableNodeTest]/[method:shouldExposeMutableBackingValueCountsMap()] replaced return value with Collections.emptyMap for org/egothor/stemmer/trie/MutableNode::valueCounts → KILLED

Active mutators

Tests examined


Report generated by PIT 1.22.1