com.github.chaosfirebolt.converter.api.cache.BaseCache Maven / Gradle / Ivy

Go to download
package com.github.chaosfirebolt.converter.api.cache;

import java.util.Objects;
import java.util.Optional;
import java.util.function.Function;
import java.util.function.Supplier;

/**
 * Base class for {@link Cache} implementations.
 *
 * @param  type of the key, by which the value is saved
 * @param  type of the cached value
 * @deprecated deprecated in favour of {@link DefaultCache}
 */
@Deprecated(since = "3.3.0", forRemoval = true)
public abstract class BaseCache implements Cache {

  private final Function computation;
  private final Supplier exceptionSupplier;

  /**
   * Constructs an instance with the specified computation and exception supplier
   *
   * @param computation       function to compute the value, if a cache is not found
   * @param exceptionSupplier supplier for an exception to be thrown, if a value can't be returned
   */
  protected BaseCache(Function computation, Supplier exceptionSupplier) {
    this.computation = computation;
    this.exceptionSupplier = exceptionSupplier;
  }

  /**
   * @param key key to search the value by
   * @return the value
   * @throws RuntimeException     thrown if unable to return a value, more specifically provided implementations will throw an {@link com.github.chaosfirebolt.converter.api.InvalidResultException},
   *                              instead of returning {@code null}.
   * @throws NullPointerException if key is null
   */
  @Override
  public final V getValue(K key) {
    return computeIfAbsent(Objects.requireNonNull(key, "Key can't be null"), this.computation).orElseThrow(this.exceptionSupplier);
  }

  /**
   * Computes and returns an optional value
   *
   * @param key         key to search the value by
   * @param computation computation to invoke, if there is no cached value
   * @return an optional value
   */
  protected abstract Optional computeIfAbsent(K key, Function computation);
}