content: /*
   * Created on Oct 17, 2010
   *
   * 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.
   *
   * Copyright @2010-2012 the original author or authors.
   */
  package org.fest.assertions.internal;
  
  import static org.fest.assertions.error.NotEqualErrorFactory.shouldBeEqual;
  import static org.fest.assertions.error.ShouldBeGreaterThan.shouldBeGreaterThan;
  import static org.fest.assertions.error.ShouldBeLessThan.shouldBeLessThan;
  import static org.fest.assertions.error.ShouldNotBeEqual.shouldNotBeEqual;
  import static org.fest.assertions.error.ShouldNotBeGreaterThan.shouldNotBeGreaterThan;
  import static org.fest.assertions.error.ShouldNotBeLessThan.shouldNotBeLessThan;
  
  import org.fest.assertions.description.Description;
  import org.fest.util.VisibleForTesting;
  
  /**
   * Reusable assertions for {@link Comparable}s.
   *
   * @author Alex Ruiz
   */
  public class Comparables {
    private static final Comparables INSTANCE = new Comparables();
  
    public static Comparables instance() {
      return INSTANCE;
    }
  
    @VisibleForTesting
    Failures failures = Failures.instance();
  
    @VisibleForTesting
    Comparables() {}
  
    @VisibleForTesting
    void setFailures(Failures failures) {
      this.failures = failures;
    }
  
    /**
     * Asserts that two values are equal by invoking {@link Comparable#compareTo(Object)}.
     *
     * @param description the description of the <em>actual</em> value.
     * @param actual the <em>actual</em> value.
     * @param expected the <em>expected</em> value.
     * @throws AssertionError if the <em>actual</em> value is {@code null}.
     * @throws AssertionError if the <em>actual</em> value is not equal to the expected one. This method will throw a
     *           {@code org.junit.ComparisonFailure} instead if JUnit is in the classpath and the expected and actual
     *           values are not equal.
     */
    public <T extends Comparable<T>> void assertEqual(Description description, T actual, T expected) {
      assertNotNull(description, actual);
      if (!areEqual(actual, expected)) {
        throw shouldBeEqual(actual, expected).newAssertionError(description);
      }
    }
  
    /**
     * Asserts that two values are not equal by invoking {@link Comparable#compareTo(Object)}.
     *
     * @param description the description of the <em>actual</em> value.
     * @param actual the <em>actual</em> value.
     * @param other the value to compare the <em>actual</em> value to.
     * @throws AssertionError if the <em>actual</em> value is {@code null}.
     * @throws AssertionError if the <em>actual</em> value is equal to the other one.
     */
    public <T extends Comparable<T>> void assertNotEqual(Description description, T actual, T other) {
      assertNotNull(description, actual);
      if (areEqual(actual, other)) {
        throw failures.failure(description, shouldNotBeEqual(actual, other));
      }
    }
  
    private <T extends Comparable<T>> boolean areEqual(T actual, T expected) {
      return actual.compareTo(expected) == 0;
    }
  
    /**
     * Asserts that the <em>actual</em> value is less than the other one.
     *
     * @param description the description of the <em>actual</em> value.
     * @param actual the <em>actual</em> value.
     * @param other the value to compare the <em>actual</em> value to.
     * @throws AssertionError if the <em>actual</em> value is {@code null}.
     * @throws AssertionError if the <em>actual</em> value is not less than the other one.
     */
    public <T extends Comparable<T>> void assertLessThan(Description description, T actual, T other) {
      assertNotNull(description, actual);
      if (!isLessThan(actual, other)) {
        throw failures.failure(description, shouldBeLessThan(actual, other));
      }
    }
  
    /**
     * Asserts that the <em>actual</em> value is greater than or equal to the other one.
     *
     * @param description the description of the <em>actual</em> value.
     * @param actual the <em>actual</em> value.
     * @param other the value to compare the actual value to.
     * @throws AssertionError if the <em>actual</em> value is {@code null}.
     * @throws AssertionError if the <em>actual</em> value is less than the other one.
     */
    public <T extends Comparable<T>> void assertNotLessThan(Description description, T actual, T other) {
      assertNotNull(description, actual);
      if (isLessThan(actual, other)) {
        throw failures.failure(description, shouldNotBeLessThan(actual, other));
      }
    }
  
    private static <T extends Comparable<T>> boolean isLessThan(T actual, T other) {
      return actual.compareTo(other) < 0;
    }
  
    /**
     * Asserts that the <em>actual</em> value is greater than the other one.
     *
     * @param description the description of the <em>actual</em> value.
     * @param actual the <em>actual</em> value.
     * @param other the value to compare the <em>actual</em> value to.
     * @throws AssertionError if the <em>actual</em> value is {@code null}.
     * @throws AssertionError if the <em>actual</em> value is not greater than the other one.
     */
    public <T extends Comparable<T>> void assertGreaterThan(Description description, T actual, T other) {
      assertNotNull(description, actual);
      if (!isGreaterThan(actual, other)) {
        throw failures.failure(description, shouldBeGreaterThan(actual, other));
      }
    }
  
    /**
     * Asserts that the <em>actual</em> value is less than or equal to the other one.
     *
     * @param description the description of the <em>actual</em> value.
     * @param actual the <em>actual</em> value.
     * @param other the value to compare the <em>actual</em> value to.
     * @throws AssertionError if the <em>actual</em> value is {@code null}.
     * @throws AssertionError if the <em>actual</em> value is greater than the other one.
     */
    public <T extends Comparable<T>> void assertNotGreaterThan(Description description, T actual, T other) {
      assertNotNull(description, actual);
      if (isGreaterThan(actual, other)) {
        throw failures.failure(description, shouldNotBeGreaterThan(actual, other));
      }
    }
  
    private static <T extends Comparable<T>> boolean isGreaterThan(T actual, T other) {
      return actual.compareTo(other) > 0;
    }
  
    protected static <T> void assertNotNull(Description description, T actual) {
      Objects.instance().assertNotNull(description, actual);
    }
  }
  