75 * then it must be the case that {@code r.equals(copy)}.
76 *
77 * @apiNote
78 * A record class that {@code implements} {@link java.io.Serializable} is said
79 * to be a <i>serializable record</i>. Serializable records are serialized and
80 * deserialized differently than ordinary serializable objects. During
81 * deserialization the record's canonical constructor is invoked to construct
82 * the record object. Certain serialization-related methods, such as readObject
83 * and writeObject, are ignored for serializable records. More information about
84 * serializable records can be found in
85 * <a href="{@docRoot}/java.base/java/io/ObjectInputStream.html#record-serialization">record serialization</a>.
86 *
87 * @jls 8.10 Record Types
88 * @since 14
89 */
90 @jdk.internal.PreviewFeature(feature=jdk.internal.PreviewFeature.Feature.RECORDS,
91 essentialAPI=true)
92 public abstract class Record {
93 /**
94 * Indicates whether some other object is "equal to" this one. In addition
95 * to the general contract of {@link Object#equals(Object)},
96 * record classes must further participate in the invariant that when
97 * a record instance is "copied" by passing the result of the record component
98 * accessor methods to the canonical constructor, as follows:
99 * <pre>
100 * R copy = new R(r.c1(), r.c2(), ..., r.cn());
101 * </pre>
102 * then it must be the case that {@code r.equals(copy)}.
103 *
104 * @implSpec
105 * The implicitly provided implementation returns {@code true} if and
106 * only if the argument is an instance of the same record type as this object,
107 * and each component of this record is equal to the corresponding component
108 * of the argument, according to {@link java.util.Objects#equals(Object,Object)}
109 * for components whose types are reference types, and according to the semantics
110 * of the {@code equals} method on the corresponding primitive wrapper type.
111 *
112 * @see java.util.Objects#equals(Object,Object)
113 *
114 * @param obj the reference object with which to compare.
115 * @return {@code true} if this object is the same as the obj
116 * argument; {@code false} otherwise.
117 */
118 @Override
119 public abstract boolean equals(Object obj);
120
121 /**
122 * Obeys the general contract of {@link Object#hashCode Object.hashCode}.
123 *
124 * @implSpec
125 * The implicitly provided implementation returns a hash code value derived
126 * by combining the hash code value for all the components, according to
127 * {@link Object#hashCode()} for components whose types are reference types,
128 * or the primitive wrapper hash code for components whose types are primitive
129 * types.
130 *
131 * @see Object#hashCode()
132 *
133 * @return a hash code value for this object.
134 */
135 @Override
|
75 * then it must be the case that {@code r.equals(copy)}.
76 *
77 * @apiNote
78 * A record class that {@code implements} {@link java.io.Serializable} is said
79 * to be a <i>serializable record</i>. Serializable records are serialized and
80 * deserialized differently than ordinary serializable objects. During
81 * deserialization the record's canonical constructor is invoked to construct
82 * the record object. Certain serialization-related methods, such as readObject
83 * and writeObject, are ignored for serializable records. More information about
84 * serializable records can be found in
85 * <a href="{@docRoot}/java.base/java/io/ObjectInputStream.html#record-serialization">record serialization</a>.
86 *
87 * @jls 8.10 Record Types
88 * @since 14
89 */
90 @jdk.internal.PreviewFeature(feature=jdk.internal.PreviewFeature.Feature.RECORDS,
91 essentialAPI=true)
92 public abstract class Record {
93 /**
94 * Indicates whether some other object is "equal to" this one. In addition
95 * to the general contract of {@link Object#equals(Object) Object.equals},
96 * record classes must further obey the invariant that when
97 * a record instance is "copied" by passing the result of the record component
98 * accessor methods to the canonical constructor, as follows:
99 * <pre>
100 * R copy = new R(r.c1(), r.c2(), ..., r.cn());
101 * </pre>
102 * then it must be the case that {@code r.equals(copy)}.
103 *
104 * @implSpec
105 * The implicitly provided implementation returns {@code true} if
106 * and only if the argument is an instance of the same record type
107 * as this object, and each component of this record is equal to
108 * the corresponding component of the argument; otherwise, {@code
109 * false} is returned. Equality of a component {@code c} is
110 * determined as follows:
111 * <ul>
112 *
113 * <li> If the component is of a reference type, the component is
114 * considered equal if and only if {@link
115 * java.util.Objects#equals(Object,Object)
116 * Objects.equals(this.c(), r.c()} would return {@code true}.
117 *
118 * <li> If the component is of a primitive type, using the
119 * corresponding primitive wrapper class {@code PW} (the wrapper
120 * class {@code java.lang.Integer} for {@code int}, and so on) the
121 * component is considered equal if and only if {@code
122 * PW.valueOf(this.c()).equals(PW.valueOf(r.c()))} would return
123 * {@code true}.
124 *
125 * </ul>
126 *
127 * The implicitly provided implementation conforms to the
128 * semantics described above; the implementation may or may not
129 * accomplish this by using calls to the particular methods
130 * listed.
131 *
132 * @see java.util.Objects#equals(Object,Object)
133 *
134 * @param obj the reference object with which to compare.
135 * @return {@code true} if this object is equal to the
136 * argument; {@code false} otherwise.
137 */
138 @Override
139 public abstract boolean equals(Object obj);
140
141 /**
142 * Obeys the general contract of {@link Object#hashCode Object.hashCode}.
143 *
144 * @implSpec
145 * The implicitly provided implementation returns a hash code value derived
146 * by combining the hash code value for all the components, according to
147 * {@link Object#hashCode()} for components whose types are reference types,
148 * or the primitive wrapper hash code for components whose types are primitive
149 * types.
150 *
151 * @see Object#hashCode()
152 *
153 * @return a hash code value for this object.
154 */
155 @Override
|