XMLElement


1   package org.enhydra.shark.xpdl;
2   
3   import java.io.Serializable  ;
4   
5   /**
6    * Base class for representing elements from XML schema.
7    *
8    * @author Sasa Bojanic
9    */
10  public abstract class XMLElement implements Serializable  , Cloneable   {
11  
12     /**
13      * Equivalent for XML element name. Used when writting instance of this class to XML file.
14      */
15     private String   name;
16  
17     /**
18      * Indicates if element is required - corresponds to the same XML element definition.
19      */
20     private boolean isRequired = false;
21  
22     /**
23      * Supposed to contain the value for XML element. This is true for simple elements and
24      * attributes, more complex elements uses it as they need.
25      */
26     protected String   value;
27  
28     /**
29      * Indicates if an element is read only.
30      */
31     protected boolean isReadOnly = false;
32  
33     /**
34      * Reference to parent object in DOM tree.
35      */
36     protected XMLElement parent;
37  
38     /**
39      * Creates a new instance of element: sets <code>name</code> to name of concrete class
40      * implementation of this abstract class, and <code>parent</code> and <code>isRequired</code>
41      * properties to the specified ones.
42      * <p>
43      * It also sets the value of this element to an empty String.
44      */
45     public XMLElement(XMLElement parent, boolean isRequired) {
46        this.parent = parent;
47        this.isRequired = isRequired;
48        this.name = getClass().getName();
49        this.name = XMLUtil.getShortClassName(name);
50        this.value = new String  ();
51     }
52  
53     /**
54      * Creates a new instance of element: sets <code>name</code>,
55      * <code>parent</code> <code>isRequired</code> properties to specified ones.
56      * <p>
57      * It also sets the value of this element to an empty String.
58      */
59     public XMLElement(XMLElement parent, String   name, boolean isRequired) {
60        this.parent = parent;
61        this.name = name;
62        this.isRequired = isRequired;
63        this.value = new String  ();
64     }
65  
66     /**
67      * Sets 'read only' property of element to specified value. This enables/disables editing of the
68      * element value for the simple elements and attributes, or changes to attributes and elements of
69      * complex objects and collections.
70      * <p>
71      * If element is read only, and one wants to change its property, the RuntimeException will be
72      * thrown.
73      */
74     public void setReadOnly(boolean ro) {
75        this.isReadOnly = ro;
76     }
77  
78     /**
79      * Returns the 'read only' status of element.
80      * <p>
81      * If element is read only, and one wants to change its property, the RuntimeException will be
82      * thrown.
83      */
84     public boolean isReadOnly() {
85        return isReadOnly;
86     }
87  
88     /**
89      * Returns if the element is required or not, which is defined by XPDL schema. If element is
90      * required, its value must be defined (In the case of complex elements, all the required
91      * subelements must be defined). Otherwise, the whole Package won't be valid by the XPDL schema.
92      */
93     public boolean isRequired() {
94        return isRequired;
95     }
96  
97     /**
98      * Indicates if element is empty.
99      */
100    public boolean isEmpty() {
101       return !(value != null && value.trim().length() > 0);
102    }
103 
104    /**
105     * Sets the element value. If it is simple element or an non-choice attribute, this sets the
106     * actual value of the element. If it is choice attribute, it sets the choosen value. Only some
107     * complex elements (Condition, SchemaType, and ExtendedAttribute) allows you to use this method,
108     * while others will throw RuntimeException.
109     */
110    public void setValue(String   v) {
111       if (isReadOnly) {
112          throw new RuntimeException  ("Can't set the value of read only element!");
113       }
114       this.value = v;
115    }
116 
117    /**
118     * Returns the element value.
119     */
120    public String   toValue() {
121       return value;
122    }
123 
124    /**
125     * Returns the name of element.
126     */
127    public String   toName() {
128       return name;
129    }
130 
131    /** Gets the parent element in DOM tree. */
132    public XMLElement getParent() {
133       return parent;
134    }
135 
136    /**
137     * Sets the parent element in DOM tree.
138     * <p>
139     * This method is used when collection, complex element or complex choice is cloned, to set new
140     * parent element of the cloned sub-elements.
141     */
142    public void setParent(XMLElement el) {
143       this.parent = el;
144    }
145 
146    /**
147     * Used to create exact copy of the element.
148     */
149    public Object   clone() {
150       XMLElement d = null;
151       try {
152          //System.out.println("Cloning XMLELement "+name);
153          d = (XMLElement) super.clone();
154          d.name = new String  (this.name);
155          d.value = new String  (this.value);
156          d.isRequired = this.isRequired;
157          d.isReadOnly = this.isReadOnly;
158          d.parent = this.parent;
159       } catch (CloneNotSupportedException   ex) {
160          // Won't happen because we implement Cloneable
161          throw new Error  (ex.toString());
162       }
163       return d;
164    }
165 
166    public boolean equals(Object   e) {
167       if (this == e)
168          return true;
169 //System.out.println("Checking eq for el "+e+" with el "+this);
170       if (e != null && e instanceof XMLElement && e.getClass().equals(this.getClass())) {
171 //System.out.println("Els are the same class");
172          XMLElement el = (XMLElement) e;
173          // TODO: do we need to check isReadOnly for equality?
174          return (this.name.equals(el.name) &&
175                   this.value.equals(el.value) &&
176                   this.isRequired == el.isRequired);
177          //&& (this.parent == null ? el.parent == null : this.parent.equals(el.parent)));
178       }/* else {
179          System.out.println("Els are not the same class: el="+e+",  this="+this);
180 
181       }*/
182       return false;
183    }
184 
185 }
186 
187
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