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src/java.base/share/classes/java/io/ObjectStreamField.java

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 37  * @since 1.2
 38  */
 39 public class ObjectStreamField
 40     implements Comparable<Object>
 41 {
 42 
 43     /** field name */
 44     private final String name;
 45     /** canonical JVM signature of field type, if given */
 46     private final String signature;
 47     /** field type (Object.class if unknown non-primitive type) */
 48     private final Class<?> type;
 49     /** lazily constructed signature for the type, if no explicit signature */
 50     private String typeSignature;
 51     /** whether or not to (de)serialize field values as unshared */
 52     private final boolean unshared;
 53     /** corresponding reflective field object, if any */
 54     private final Field field;
 55     /** offset of field value in enclosing field group */
 56     private int offset;


 57 
 58     /**
 59      * Create a Serializable field with the specified type.  This field should
 60      * be documented with a {@code serialField} tag.
 61      *
 62      * @param   name the name of the serializable field
 63      * @param   type the {@code Class} object of the serializable field
 64      */
 65     public ObjectStreamField(String name, Class<?> type) {
 66         this(name, type, false);
 67     }
 68 
 69     /**
 70      * Creates an ObjectStreamField representing a serializable field with the
 71      * given name and type.  If unshared is false, values of the represented
 72      * field are serialized and deserialized in the default manner--if the
 73      * field is non-primitive, object values are serialized and deserialized as
 74      * if they had been written and read by calls to writeObject and
 75      * readObject.  If unshared is true, values of the represented field are
 76      * serialized and deserialized as if they had been written and read by
 77      * calls to writeUnshared and readUnshared.
 78      *
 79      * @param   name field name
 80      * @param   type field type
 81      * @param   unshared if false, write/read field values in the same manner
 82      *          as writeObject/readObject; if true, write/read in the same
 83      *          manner as writeUnshared/readUnshared
 84      * @since   1.4
 85      */
 86     public ObjectStreamField(String name, Class<?> type, boolean unshared) {





 87         if (name == null) {
 88             throw new NullPointerException();
 89         }
 90         this.name = name;
 91         this.type = type;
 92         this.unshared = unshared;
 93         this.field = null;
 94         this.signature = null;

 95     }
 96 
 97     /**
 98      * Creates an ObjectStreamField representing a field with the given name,
 99      * signature and unshared setting.
100      */
101     ObjectStreamField(String name, String signature, boolean unshared) {
102         if (name == null) {
103             throw new NullPointerException();
104         }
105         this.name = name;
106         this.signature = signature.intern();
107         this.unshared = unshared;
108         this.field = null;

109 
110         type = switch (signature.charAt(0)) {
111             case 'Z'      -> Boolean.TYPE;
112             case 'B'      -> Byte.TYPE;
113             case 'C'      -> Character.TYPE;
114             case 'S'      -> Short.TYPE;
115             case 'I'      -> Integer.TYPE;
116             case 'J'      -> Long.TYPE;
117             case 'F'      -> Float.TYPE;
118             case 'D'      -> Double.TYPE;
119             case 'L', '[' -> Object.class;
120             default       -> throw new IllegalArgumentException("illegal signature");
121         };
122     }
123 
124     /**
125      * Creates an ObjectStreamField representing the given field with the
126      * specified unshared setting.  For compatibility with the behavior of
127      * earlier serialization implementations, a "showType" parameter is
128      * necessary to govern whether or not a getType() call on this
129      * ObjectStreamField (if non-primitive) will return Object.class (as
130      * opposed to a more specific reference type).
131      */
132     ObjectStreamField(Field field, boolean unshared, boolean showType) {
133         this.field = field;
134         this.unshared = unshared;
135         name = field.getName();
136         Class<?> ftype = field.getType();
137         type = (showType || ftype.isPrimitive()) ? ftype : Object.class;
138         signature = ftype.descriptorString().intern();

139     }
140 
141     /**
142      * Get the name of this field.
143      *
144      * @return  a {@code String} representing the name of the serializable
145      *          field
146      */
147     public String getName() {
148         return name;
149     }
150 
151     /**
152      * Get the type of the field.  If the type is non-primitive and this
153      * {@code ObjectStreamField} was obtained from a deserialized {@link
154      * ObjectStreamClass} instance, then {@code Object.class} is returned.
155      * Otherwise, the {@code Class} object for the type of the field is
156      * returned.
157      *
158      * @return  a {@code Class} object representing the type of the

199      *
200      * @return  the offset of this field
201      * @see #setOffset
202      */
203     // REMIND: deprecate?
204     public int getOffset() {
205         return offset;
206     }
207 
208     /**
209      * Offset within instance data.
210      *
211      * @param   offset the offset of the field
212      * @see #getOffset
213      */
214     // REMIND: deprecate?
215     protected void setOffset(int offset) {
216         this.offset = offset;
217     }
218 







219     /**
220      * Return true if this field has a primitive type.
221      *
222      * @return  true if and only if this field corresponds to a primitive type
223      */
224     // REMIND: deprecate?
225     public boolean isPrimitive() {
226         char tcode = getTypeCode();
227         return ((tcode != 'L') && (tcode != '['));
228     }
229 
230     /**
231      * Returns boolean value indicating whether or not the serializable field
232      * represented by this ObjectStreamField instance is unshared.
233      *
234      * @return {@code true} if this field is unshared
235      *
236      * @since 1.4
237      */
238     public boolean isUnshared() {

 37  * @since 1.2
 38  */
 39 public class ObjectStreamField
 40     implements Comparable<Object>
 41 {
 42 
 43     /** field name */
 44     private final String name;
 45     /** canonical JVM signature of field type, if given */
 46     private final String signature;
 47     /** field type (Object.class if unknown non-primitive type) */
 48     private final Class<?> type;
 49     /** lazily constructed signature for the type, if no explicit signature */
 50     private String typeSignature;
 51     /** whether or not to (de)serialize field values as unshared */
 52     private final boolean unshared;
 53     /** corresponding reflective field object, if any */
 54     private final Field field;
 55     /** offset of field value in enclosing field group */
 56     private int offset;
 57     /** index of the field in the class, retain the declaration order of serializable fields */
 58     private final int argIndex;
 59 
 60     /**
 61      * Create a Serializable field with the specified type.  This field should
 62      * be documented with a {@code serialField} tag.
 63      *
 64      * @param   name the name of the serializable field
 65      * @param   type the {@code Class} object of the serializable field
 66      */
 67     public ObjectStreamField(String name, Class<?> type) {
 68         this(name, type, false);
 69     }
 70 
 71     /**
 72      * Creates an ObjectStreamField representing a serializable field with the
 73      * given name and type.  If unshared is false, values of the represented
 74      * field are serialized and deserialized in the default manner--if the
 75      * field is non-primitive, object values are serialized and deserialized as
 76      * if they had been written and read by calls to writeObject and
 77      * readObject.  If unshared is true, values of the represented field are
 78      * serialized and deserialized as if they had been written and read by
 79      * calls to writeUnshared and readUnshared.
 80      *
 81      * @param   name field name
 82      * @param   type field type
 83      * @param   unshared if false, write/read field values in the same manner
 84      *          as writeObject/readObject; if true, write/read in the same
 85      *          manner as writeUnshared/readUnshared
 86      * @since   1.4
 87      */
 88     public ObjectStreamField(String name, Class<?> type, boolean unshared) {
 89         this(name, type, unshared, -1);
 90     }
 91 
 92     /* package-private */
 93     ObjectStreamField(String name, Class<?> type, boolean unshared, int argIndex) {
 94         if (name == null) {
 95             throw new NullPointerException();
 96         }
 97         this.name = name;
 98         this.type = type;
 99         this.unshared = unshared;
100         this.field = null;
101         this.signature = null;
102         this.argIndex = argIndex;
103     }
104 
105     /**
106      * Creates an ObjectStreamField representing a field with the given name,
107      * signature and unshared setting.
108      */
109     ObjectStreamField(String name, String signature, boolean unshared, int argIndex) {
110         if (name == null) {
111             throw new NullPointerException();
112         }
113         this.name = name;
114         this.signature = signature.intern();
115         this.unshared = unshared;
116         this.field = null;
117         this.argIndex = argIndex;
118 
119         type = switch (signature.charAt(0)) {
120             case 'Z'      -> Boolean.TYPE;
121             case 'B'      -> Byte.TYPE;
122             case 'C'      -> Character.TYPE;
123             case 'S'      -> Short.TYPE;
124             case 'I'      -> Integer.TYPE;
125             case 'J'      -> Long.TYPE;
126             case 'F'      -> Float.TYPE;
127             case 'D'      -> Double.TYPE;
128             case 'L', '[' -> Object.class;
129             default       -> throw new IllegalArgumentException("illegal signature");
130         };
131     }
132 
133     /**
134      * Creates an ObjectStreamField representing the given field with the
135      * specified unshared setting.  For compatibility with the behavior of
136      * earlier serialization implementations, a "showType" parameter is
137      * necessary to govern whether or not a getType() call on this
138      * ObjectStreamField (if non-primitive) will return Object.class (as
139      * opposed to a more specific reference type).
140      */
141     ObjectStreamField(Field field, boolean unshared, boolean showType, int argIndex) {
142         this.field = field;
143         this.unshared = unshared;
144         name = field.getName();
145         Class<?> ftype = field.getType();
146         type = (showType || ftype.isPrimitive()) ? ftype : Object.class;
147         signature = ftype.descriptorString().intern();
148         this.argIndex = argIndex;
149     }
150 
151     /**
152      * Get the name of this field.
153      *
154      * @return  a {@code String} representing the name of the serializable
155      *          field
156      */
157     public String getName() {
158         return name;
159     }
160 
161     /**
162      * Get the type of the field.  If the type is non-primitive and this
163      * {@code ObjectStreamField} was obtained from a deserialized {@link
164      * ObjectStreamClass} instance, then {@code Object.class} is returned.
165      * Otherwise, the {@code Class} object for the type of the field is
166      * returned.
167      *
168      * @return  a {@code Class} object representing the type of the

209      *
210      * @return  the offset of this field
211      * @see #setOffset
212      */
213     // REMIND: deprecate?
214     public int getOffset() {
215         return offset;
216     }
217 
218     /**
219      * Offset within instance data.
220      *
221      * @param   offset the offset of the field
222      * @see #getOffset
223      */
224     // REMIND: deprecate?
225     protected void setOffset(int offset) {
226         this.offset = offset;
227     }
228 
229     /**
230      * {@return Index of the field in the sequence of Serializable fields}
231      */
232     int getArgIndex() {
233         return argIndex;
234     }
235 
236     /**
237      * Return true if this field has a primitive type.
238      *
239      * @return  true if and only if this field corresponds to a primitive type
240      */
241     // REMIND: deprecate?
242     public boolean isPrimitive() {
243         char tcode = getTypeCode();
244         return ((tcode != 'L') && (tcode != '['));
245     }
246 
247     /**
248      * Returns boolean value indicating whether or not the serializable field
249      * represented by this ObjectStreamField instance is unshared.
250      *
251      * @return {@code true} if this field is unshared
252      *
253      * @since 1.4
254      */
255     public boolean isUnshared() {
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