content: /**
   * Copyright (c) 2013, Andre Steingress
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
   * following conditions are met:
   *
   * 1.) Redistributions of source code must retain the above copyright notice, this list of conditions and the following
   * disclaimer.
   * 2.) Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
   * disclaimer in the documentation and/or other materials provided with the distribution.
   * 3.) Neither the name of Andre Steingress nor the names of its contributors may be used to endorse or
   * promote products derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
   * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
   * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
   * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  package org.gcontracts.annotations;
  
  import org.gcontracts.annotations.meta.AnnotationProcessorImplementation;
  import org.gcontracts.annotations.meta.Postcondition;
  import org.gcontracts.common.impl.EnsuresAnnotationProcessor;
  
  import java.lang.annotation.ElementType;
  import java.lang.annotation.Retention;
  import java.lang.annotation.RetentionPolicy;
  import java.lang.annotation.Target;
  
  /**
   * <p>
   * Represents a <b>method postcondition</b>.
   * </p>
   * <p>
   * A postcondition is a condition that is guaranteed to be fulfilled by suppliers.
   * </p>
   * <p>
   * A method's postcondition is executed <i>after</i> a method call
   * has finished. A successor's postcondition strengthens the postcondition of its parent class, e.g. if A.someMethod
   * declares a postcondition and B.someMethod overrides the method the postconditions are combined with a boolean AND.
   * </p>
   * <p>
   * Compared to pre-conditions, postcondition annotation closures are optionally called with two additional
   * closure arguments: <tt>result</tt> and <tt>old</tt>.
   * </p>
   * <p>
   * <tt>result</tt> is available if the corresponding method has a non-void return-type and holds the
   * result of the method call. Be aware that modifying the internal state of a reference type can lead
   * to side-effects. GContracts does not keep track of any sort of modifications, neither any conversion to
   * immutability.
   * </p>
   * <p>
   * <tt>old</tt> is available in every postcondition. It is a {@link java.util.Map} which holds the values
   * of value types and {@link Cloneable} types before the method has been executed.
   * </p>
   * <p>
   * Examples:
   *
   * Accessing the <tt>result</tt> closure parameter:
   * 
   * <pre>
   *   &#064;Ensures({ result -> result != argument1 })
   *   def T someOperation(def argument1, def argument2)  {
   *     ...
   *   }
   * </pre>
   * 
   * Accessing the <tt>old</tt> closure parameter:
   * 
   * <pre>
   *   &#064;Ensures({ old -> old.counter + 1 == counter })
   *   def T someOperation(def argument1, def argument2)  {
   *     ...
   *   }
   * </pre>
   * </p>
   *
   * @author ast
   */
  @Retention(RetentionPolicy.RUNTIME)
  @Target({ElementType.CONSTRUCTOR, ElementType.METHOD})
  
  @Postcondition
  @AnnotationProcessorImplementation(EnsuresAnnotationProcessor.class)
  public @interface Ensures {
      public abstract Class value();
  }