content: /*
   *  Licensed to the Apache Software Foundation (ASF) under one
   *  or more contributor license agreements.  See the NOTICE file
   *  distributed with this work for additional information
   *  regarding copyright ownership.  The ASF licenses this file
   *  to you 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.apache.causeway.applib.annotation;
  
  import java.lang.annotation.ElementType;
  import java.lang.annotation.Inherited;
  import java.lang.annotation.Retention;
  import java.lang.annotation.RetentionPolicy;
  import java.lang.annotation.Target;
  
  import org.apache.causeway.applib.spec.Specification;
  import org.apache.causeway.applib.value.Blob;
  import org.apache.causeway.applib.value.Clob;
  
  /**
   * Collects together all domain semantics of an action parameter within a
   * single annotation.
   *
   * @see Action
   * @see Property
   * @see ParameterLayout
   *
   * @since 1.x {@index}
   */
  @Inherited
  @Target({
          ElementType.PARAMETER,
          ElementType.ANNOTATION_TYPE
  })
  @Retention(RetentionPolicy.RUNTIME)
  public @interface Parameter {
  
      /**
       * For uploading {@link Blob} or {@link Clob}, optionally restrict the files accepted (eg <tt>.xslx</tt>).
       *
       * <p>
       * The value should be of the form "file_extension|audio/*|video/*|image/*|media_type".
       * </p>
       *
       * <p>
       *     Note that this does not prevent the user from uploading some other file type; rather it merely defaults the
       *     file type in the file open dialog.
       * </p>
       *
       * @see Action#fileAccept()
       * @see Property#fileAccept()
       * @see <a href="http://www.w3schools.com/tags/att_input_accept.asp">http://www.w3schools.com</a>
       */
      String fileAccept()
              default "";
  
      /**
       * The maximum entry length of a string parameter (it is ignored for other
       * types).
       *
       * <p>
       *     The default value (<code>-1</code>) indicates that no maxLength has
       *     been specified.
       * </p>
       *
       * @see Property#maxLength()
       */
      int maxLength()
              default -1;
  
      /**
       * The {@link org.apache.causeway.applib.spec.Specification}(s) to be satisfied by this parameter.
       *
       * <p>
       * If more than one is provided, then all must be satisfied (in effect &quot;AND&quot;ed together).
       * </p>
       *
       * @see Property#mustSatisfy()
       */
      Class<? extends Specification>[] mustSatisfy()
              default {};
  
      /**
       * Whether this parameter is optional or is mandatory (ie required).
       *
       * <p>
       *     For parameters the default value, {@link org.apache.causeway.applib.annotation.Optionality#DEFAULT}, is taken
       *     to mean that the parameter is required.
       * </p>
       *
       * @see Property#optionality()
       */
      Optionality optionality()
              default Optionality.NOT_SPECIFIED;
  
      /**
       * Regular expression pattern that a value should conform to, and can be formatted as.
       *
       * @see Property#regexPattern()
       * @see Parameter#regexPatternReplacement()
       * @see Parameter#regexPatternFlags()
       */
      String regexPattern()
              default "";
  
      /**
       * Pattern flags, as per {@link java.util.regex.Pattern#compile(String, int)} .
       *
       * <p>
       *     The default value, <code>0</code>, means that no flags have been specified.
       * </p>
       *
       * @see Parameter#regexPattern()
       */
      int regexPatternFlags()
              default 0;
  
      /**
       * Replacement text for the pattern in generated error message.
       *
       * @see Parameter#regexPattern()
       */
      String regexPatternReplacement()
              default "Doesn't match pattern";
  
      /**
       * Whether parameter values should be reset to their default if an earlier parameter changes its
       * value, or whether instead a parameter value, once changed by the end-user, should never be
       * overwritten even if the end-user changes an earlier parameter value.
       */
      PrecedingParamsPolicy precedingParamsPolicy()
              default PrecedingParamsPolicy.AS_CONFIGURED;
  
  }
  