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Instrumentation of Java libraries using OpenTelemetry.

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/*
 * Copyright The OpenTelemetry Authors
 * SPDX-License-Identifier: Apache-2.0
 */

package io.opentelemetry.javaagent.tooling.util;

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import javax.annotation.Nullable;

/** A prefix tree that maps from the longest matching prefix to a value {@code V}. */
public interface Trie {

  /** Start building a trie. */
  static  Builder builder() {
    return new TrieImpl.BuilderImpl<>();
  }

  /**
   * Returns the value associated with the longest matched prefix, or null if there wasn't a match.
   * For example: for a trie containing an {@code ("abc", 10)} entry {@code trie.getOrNull("abcd")}
   * will return {@code 10}.
   */
  @Nullable
  default V getOrNull(CharSequence str) {
    return getOrDefault(str, null);
  }

  /**
   * Returns the value associated with the longest matched prefix, or the {@code defaultValue} if
   * there wasn't a match. For example: for a trie containing an {@code ("abc", 10)} entry {@code
   * trie.getOrDefault("abcd", -1)} will return {@code 10}.
   */
  V getOrDefault(CharSequence str, V defaultValue);

  /** Returns {@code true} if this trie contains the prefix {@code str}. */
  default boolean contains(CharSequence str) {
    return getOrNull(str) != null;
  }

  interface Builder {

    /** Associate {@code value} with the string {@code str}. */
    @CanIgnoreReturnValue
    Builder put(CharSequence str, V value);

    Trie build();
  }
}