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1   /*
2    * Copyright (C) 2007-2012 Argeo GmbH
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    *         http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.argeo.slc.execution;
17  
18  /**
19   * Possible attribute of an execution flow.
20   * 
21   * There are mainly two implementations :<br>
22   * + Primitive attributes (no predefined choice, the end user must compute a
23   * String, a Float, an Integer...)<br>
24   * + RefSpecAttribute which enable two things<br>
25   * ++ a reference to another object of the application context<br>
26   * ++ the display of some choices among which the end user can choose.<br>
27   * 
28   * @see org.argeo.slc.core.execution.PrimitiveSpecAttribute
29   * @see org.argeo.slc.core.execution.RefSpecAttribute
30   * @see org.argeo.slc.core.execution.PrimitiveUtils : this class offers some
31   *      helper, among others to cast the various type of primitive attribute.
32   */
33  public interface ExecutionSpecAttribute {
34  	/**
35  	 * Whether this attribute has to be set at instantiation of the flow and
36  	 * cannot be modified afterwards. If the attribute is not immutable (that
37  	 * is, this method returns false), it can be set at execution time.
38  	 */
39  	public Boolean getIsImmutable();
40  
41  	/**
42  	 * Whether this attribute must be explicitly set and cannot be modified.
43  	 * This attribute is then basically a constant within a given application
44  	 * context. {@link #getValue()} cannot return null if the attribute is a
45  	 * constant.
46  	 */
47  	public Boolean getIsConstant();
48  
49  	/** Whether this attribute will be hidden to end users. */
50  	public Boolean getIsHidden();
51  
52  	/**
53  	 * The default value for this attribute. Can be null, except if
54  	 * {@link #getIsFrozen()} is <code>true</code>, in which case it represents
55  	 * the constant value of this attribute.
56  	 */
57  	public Object getValue();
58  
59  	/** Description of this attribute, can be null */
60  	public String getDescription();
61  
62  	/** @deprecated use {@link #getIsImmutable()} instead */
63  	public Boolean getIsParameter();
64  
65  	/** @deprecated use {@link #getIsConstant()} instead */
66  	public Boolean getIsFrozen();
67  
68  }