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Java Simplified. Extensions and Useful Constructs for the Java Platform. Codeprimate Elements (a.k.a. cp-elements) is a Java library and micro-framework used to simplify the development of software applications written in Java. Elements packages several APIs into one library in order to address various application concerns and aspects of software design and development collectively and conveniently. Elements is a highly simple, yet robust and proven library built on solid OO principles, software design patterns and best practices to effectively solve common and reoccurring problems in software development.

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/*
 * Copyright 2016 Author or Authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.cp.elements.data.caching;

import static org.cp.elements.lang.RuntimeExceptionsFactory.newUnsupportedOperationException;

import java.util.Iterator;
import java.util.Set;

/**
 * {@link AbstractCache} is an abstract base class supporting the implementation of different {@link Cache Caches}.
 *
 * @author John Blum
 * @see java.lang.Comparable
 * @see org.cp.elements.data.caching.Cache
 * @since 1.0.0
 */
public abstract class AbstractCache, VALUE> implements Cache {

  private String name;

  /**
   * Clears the entire contents (all entries) of this {@link Cache}.
   *
   * @see #evictAll(Iterable)
   * @see #keys()
   */
  @Override
  public void clear() {
    throw new UnsupportedOperationException("Clear is not supported");
  }

  /**
   * Determines whether this {@link Cache} contains an entry mapped with the given {@link KEY key}.
   *
   * @param key {@link KEY key} to evaluate.
   * @return a boolean value indicating whether this {@link Cache} contains an entry
   * mapped with the given {@link KEY key}.
   */
  @Override
  public boolean contains(KEY key) {
    throw newUnsupportedOperationException("Contains is not supported");
  }

  /**
   * Removes the entry mapped to the given {@link KEY key} from this {@link Cache}.
   *
   * @param key {@link KEY key} identifying the entry to remove from this {@link Cache}.
   */
  @Override
  public void evict(KEY key) {
    throw newUnsupportedOperationException("Eviction is not supported");
  }

  /**
   * Gets the {@link VALUE value} mapped to the given {@link KEY} in this {@link Cache}.
   *
   * Returns {@literal null} if the {@link VALUE value} for the given {@link KEY key} is {@literal null},
   * or this {@link Cache} does not contain an entry with the given {@link KEY key}.
   *
   * @param key {@link KEY key} used to lookup the desired {@link VALUE value}.
   * @return the {@link VALUE value} mapped to the given {@link KEY key}.
   * @see #put(Comparable, Object)
   */
  @Override
  public VALUE get(KEY key) {
    throw newUnsupportedOperationException("Get is not supported");
  }

  /**
   * Returns the {@link String name} of this {@link Cache}.
   *
   * The {@link String name} may be {@literal null}.
   *
   * @return the {@link String name} of this {@link Cache}; may be {@literal null}.
   */
  @Override
  public String getName() {
    return this.name;
  }

  /**
   * Returns an {@link Iterator} iterating over the value in this {@link Cache}.
   *
   * @return an {@link Iterator} iterating over the value in this {@link Cache}.
   * @see java.util.Iterator
   */
  @Override
  public Iterator iterator() {
    throw newUnsupportedOperationException("Iterating all values is not supported");
  }

  /**
   * Returns all the {@link KEY keys} in this {@link Cache}.
   *
   * @return a {@link Set} containing all of the {@link KEY keys} in this {@link Cache}.
   * @see java.util.Set
   */
  @Override
  public Set keys() {
    throw newUnsupportedOperationException("Returning all keys is not supported");
  }

  /**
   * Puts the given {@link VALUE value} mapped to the given {@link KEY key} into this {@link Cache}.
   *
   * @param key {@link KEY} used to map the {@link VALUE value}; must not be {@literal null}.
   * @param value {@link VALUE} put into this {@link Cache} mapped to the given {@link KEY key}.
   * @throws IllegalArgumentException if {@link KEY key} is {@literal null}.
   * @see #get(Comparable)
   */
  @Override
  public void put(KEY key, VALUE value) {
    throw newUnsupportedOperationException("Put is not supported");
  }

  /**
   * Determines the number of entries contained in this {@link Cache}.
   *
   * @return an integer value with the number of entries contained in this {@link Cache}.
   * @see #isEmpty()
   */
  @Override
  public int size() {
    throw newUnsupportedOperationException("Size is not supported");
  }

  /**
   * Builder method to set the {@link String name} of this {@link Cache}.
   *
   * @param  {@link Class type} of this {@link Cache}.
   * @param name {@link String} containing the name for this {@link Cache}.
   * @return this {@link Cache}.
   */
  @SuppressWarnings("unchecked")
  public > T named(String name) {
    this.name = name;
    return (T) this;
  }
}