OpenJDK 14のソースコードの中から”@since 14″を検索して，追加されたところを見てみる。deprecatedとされた部分も検索されてしまうが，こちらは一旦無視して，追加された部分に注目する。
java.lang.Classクラス
java.lang.Classクラスにはrecordの追加に伴うメソッドが追加されている。
@jdk.internal.PreviewFeature(feature=jdk.internal.PreviewFeature.Feature.RECORDS,
essentialAPI=false)
@SuppressWarnings("preview")
@CallerSensitive
public RecordComponent[] getRecordComponents() {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), true);
}
if (!isRecord()) {
return null;
}
RecordComponent[] recordComponents = getRecordComponents0();
if (recordComponents == null) {
return new RecordComponent[0];
}
return recordComponents;
}
@jdk.internal.PreviewFeature(feature=jdk.internal.PreviewFeature.Feature.RECORDS,
essentialAPI=false)
public boolean isRecord() {
return getSuperclass() == JAVA_LANG_RECORD_CLASS && isRecord0();
}
java.lang.Recordクラス
新たに追加された主要概念の１つであるRecordを表すクラスである。抽象クラスとなっている。
/*
* Copyright (c) 2019, 2020, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.lang;
/**
* {@preview Associated with records, a preview feature of the Java language.
*
* This class is associated with <i>records</i>, a preview
* feature of the Java language. Programs can only use this
* class when preview features are enabled. Preview features
* may be removed in a future release, or upgraded to permanent
* features of the Java language.}
*
* This is the common base class of all Java language record classes.
*
* <p>More information about records, including descriptions of the
* implicitly declared methods synthesized by the compiler, can be
* found in section 8.10 of
* <cite>The Java™ Language Specification</cite>.
*
* <p>A <em>record class</em> is a shallowly immutable, transparent carrier for
* a fixed set of values, called the <em>record components</em>. The Java™
* language provides concise syntax for declaring record classes, whereby the
* record components are declared in the record header. The list of record
* components declared in the record header form the <em>record descriptor</em>.
*
* <p>A record class has the following mandated members: a public <em>canonical
* constructor</em>, whose descriptor is the same as the record descriptor;
* a private final field corresponding to each component, whose name and
* type are the same as that of the component; a public accessor method
* corresponding to each component, whose name and return type are the same as
* that of the component. If not explicitly declared in the body of the record,
* implicit implementations for these members are provided.
*
* <p>The implicit declaration of the canonical constructor initializes the
* component fields from the corresponding constructor arguments. The implicit
* declaration of the accessor methods returns the value of the corresponding
* component field. The implicit declaration of the {@link Object#equals(Object)},
* {@link Object#hashCode()}, and {@link Object#toString()} methods are derived
* from all of the component fields.
*
* <p>The primary reasons to provide an explicit declaration for the
* canonical constructor or accessor methods are to validate constructor
* arguments, perform defensive copies on mutable components, or normalize groups
* of components (such as reducing a rational number to lowest terms.)
*
* <p>For all record classes, the following invariant must hold: if a record R's
* components are {@code c1, c2, ... cn}, then if a record instance is copied
* as follows:
* <pre>
* R copy = new R(r.c1(), r.c2(), ..., r.cn());
* </pre>
* then it must be the case that {@code r.equals(copy)}.
*
* @apiNote
* A record class that {@code implements} {@link java.io.Serializable} is said
* to be a <i>serializable record</i>. Serializable records are serialized and
* deserialized differently than ordinary serializable objects. During
* deserialization the record's canonical constructor is invoked to construct
* the record object. Certain serialization-related methods, such as readObject
* and writeObject, are ignored for serializable records. More information about
* serializable records can be found in
* <a href="{@docRoot}/java.base/java/io/ObjectInputStream.html#record-serialization">record serialization</a>.
*
* @jls 8.10 Record Types
* @since 14
*/
@jdk.internal.PreviewFeature(feature=jdk.internal.PreviewFeature.Feature.RECORDS,
essentialAPI=true)
public abstract class Record {
/**
* Constructor for record classes to call.
*/
protected Record() {}
/**
* Indicates whether some other object is "equal to" this one. In addition
* to the general contract of {@link Object#equals(Object) Object.equals},
* record classes must further obey the invariant that when
* a record instance is "copied" by passing the result of the record component
* accessor methods to the canonical constructor, as follows:
* <pre>
* R copy = new R(r.c1(), r.c2(), ..., r.cn());
* </pre>
* then it must be the case that {@code r.equals(copy)}.
*
* @implSpec
* The implicitly provided implementation returns {@code true} if
* and only if the argument is an instance of the same record type
* as this object, and each component of this record is equal to
* the corresponding component of the argument; otherwise, {@code
* false} is returned. Equality of a component {@code c} is
* determined as follows:
* <ul>
*
* <li> If the component is of a reference type, the component is
* considered equal if and only if {@link
* java.util.Objects#equals(Object,Object)
* Objects.equals(this.c(), r.c()} would return {@code true}.
*
* <li> If the component is of a primitive type, using the
* corresponding primitive wrapper class {@code PW} (the
* corresponding wrapper class for {@code int} is {@code
* java.lang.Integer}, and so on), the component is considered
* equal if and only if {@code
* PW.valueOf(this.c()).equals(PW.valueOf(r.c()))} would return
* {@code true}.
*
* </ul>
*
* The implicitly provided implementation conforms to the
* semantics described above; the implementation may or may not
* accomplish this by using calls to the particular methods
* listed.
*
* @see java.util.Objects#equals(Object,Object)
*
* @param obj the reference object with which to compare.
* @return {@code true} if this object is equal to the
* argument; {@code false} otherwise.
*/
@Override
public abstract boolean equals(Object obj);
/**
* Obeys the general contract of {@link Object#hashCode Object.hashCode}.
*
* @implSpec
* The implicitly provided implementation returns a hash code value derived
* by combining the hash code value for all the components, according to
* {@link Object#hashCode()} for components whose types are reference types,
* or the primitive wrapper hash code for components whose types are primitive
* types.
*
* @see Object#hashCode()
*
* @return a hash code value for this object.
*/
@Override
public abstract int hashCode();
/**
* Obeys the general contract of {@link Object#toString Object.toString}.
*
* @implSpec
* The implicitly provided implementation returns a string that is derived
* from the name of the record class and the names and string representations
* of all the components, according to {@link Object#toString()} for components
* whose types are reference types, and the primitive wrapper {@code toString}
* method for components whose types are primitive types.
*
* @see Object#toString()
*
* @return a string representation of the object.
*/
@Override
public abstract String toString();
}
java.lang.ElementType列挙子
ElementTypeのenumに新しくRECORD_COMPONENTが追加された。レコードに対応したものと思われる。
* Record component
*
* @jls 8.10.3 Record Members
* @jls 9.7.4 Where Annotations May Appear
*
* @since 14
*/
@jdk.internal.PreviewFeature(feature=jdk.internal.PreviewFeature.Feature.RECORDS,
essentialAPI=true)
RECORD_COMPONENT;
java.lang.RecordComponentクラス
レコードを表すキモとなるクラスである。
/*
* Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.lang.reflect;
import jdk.internal.access.SharedSecrets;
import sun.reflect.annotation.AnnotationParser;
import sun.reflect.annotation.TypeAnnotation;
import sun.reflect.annotation.TypeAnnotationParser;
import sun.reflect.generics.factory.CoreReflectionFactory;
import sun.reflect.generics.factory.GenericsFactory;
import sun.reflect.generics.repository.FieldRepository;
import sun.reflect.generics.scope.ClassScope;
import java.lang.annotation.Annotation;
import java.util.Map;
import java.util.Objects;
/**
* {@preview Associated with records, a preview feature of the Java language.
*
* This class is associated with <i>records</i>, a preview
* feature of the Java language. Preview features
* may be removed in a future release, or upgraded to permanent
* features of the Java language.}
*
* A {@code RecordComponent} provides information about, and dynamic access to, a
* component of a record class.
*
* @see Class#getRecordComponents()
* @see java.lang.Record
* @jls 8.10 Record Types
* @since 14
*/
@jdk.internal.PreviewFeature(feature=jdk.internal.PreviewFeature.Feature.RECORDS,
essentialAPI=false)
public final class RecordComponent implements AnnotatedElement {
// declaring class
private Class<?> clazz;
private String name;
private Class<?> type;
private Method accessor;
private String signature;
// generic info repository; lazily initialized
private transient FieldRepository genericInfo;
private byte[] annotations;
private byte[] typeAnnotations;
@SuppressWarnings("preview")
private RecordComponent root;
// only the JVM can create record components
private RecordComponent() {}
/**
* Returns the name of this record component.
*
* @return the name of this record component
*/
public String getName() {
return name;
}
/**
* Returns a {@code Class} that identifies the declared type for this
* record component.
*
* @return a {@code Class} identifying the declared type of the component
* represented by this record component
*/
public Class<?> getType() {
return type;
}
/**
* Returns a {@code String} that describes the generic type signature for
* this record component.
*
* @return a {@code String} that describes the generic type signature for
* this record component
*
* @jvms 4.7.9.1 Signatures
*/
public String getGenericSignature() {
return signature;
}
/**
* Returns a {@code Type} object that represents the declared type for
* this record component.
*
* <p>If the declared type of the record component is a parameterized type,
* the {@code Type} object returned reflects the actual type arguments used
* in the source code.
*
* <p>If the type of the underlying record component is a type variable or a
* parameterized type, it is created. Otherwise, it is resolved.
*
* @return a {@code Type} object that represents the declared type for
* this record component
* @throws GenericSignatureFormatError if the generic record component
* signature does not conform to the format specified in
* <cite>The Java™ Virtual Machine Specification</cite>
* @throws TypeNotPresentException if the generic type
* signature of the underlying record component refers to a non-existent
* type declaration
* @throws MalformedParameterizedTypeException if the generic
* signature of the underlying record component refers to a parameterized
* type that cannot be instantiated for any reason
*/
public Type getGenericType() {
if (getGenericSignature() != null)
return getGenericInfo().getGenericType();
else
return getType();
}
// Accessor for generic info repository
private FieldRepository getGenericInfo() {
// lazily initialize repository if necessary
if (genericInfo == null) {
// create and cache generic info repository
genericInfo = FieldRepository.make(getGenericSignature(), getFactory());
}
return genericInfo; //return cached repository
}
// Accessor for factory
private GenericsFactory getFactory() {
Class<?> c = getDeclaringRecord();
// create scope and factory
return CoreReflectionFactory.make(c, ClassScope.make(c));
}
/**
* Returns an {@code AnnotatedType} object that represents the use of a type to specify
* the declared type of this record component.
*
* @return an object representing the declared type of this record component
*/
public AnnotatedType getAnnotatedType() {
return TypeAnnotationParser.buildAnnotatedType(typeAnnotations,
SharedSecrets.getJavaLangAccess().
getConstantPool(getDeclaringRecord()),
this,
getDeclaringRecord(),
getGenericType(),
TypeAnnotation.TypeAnnotationTarget.FIELD);
}
/**
* Returns a {@code Method} that represents the accessor for this record
* component.
*
* @return a {@code Method} that represents the accessor for this record
* component
*/
public Method getAccessor() {
return accessor;
}
/**
* @throws NullPointerException {@inheritDoc}
*/
@Override
public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
Objects.requireNonNull(annotationClass);
return annotationClass.cast(declaredAnnotations().get(annotationClass));
}
private transient volatile Map<Class<? extends Annotation>, Annotation> declaredAnnotations;
private Map<Class<? extends Annotation>, Annotation> declaredAnnotations() {
Map<Class<? extends Annotation>, Annotation> declAnnos;
if ((declAnnos = declaredAnnotations) == null) {
synchronized (this) {
if ((declAnnos = declaredAnnotations) == null) {
@SuppressWarnings("preview")
RecordComponent root = this.root;
if (root != null) {
declAnnos = root.declaredAnnotations();
} else {
declAnnos = AnnotationParser.parseAnnotations(
annotations,
SharedSecrets.getJavaLangAccess()
.getConstantPool(getDeclaringRecord()),
getDeclaringRecord());
}
declaredAnnotations = declAnnos;
}
}
}
return declAnnos;
}
/**
* {@inheritDoc}
*/
@Override
public Annotation[] getAnnotations() {
return getDeclaredAnnotations();
}
/**
* {@inheritDoc}
*/
@Override
public Annotation[] getDeclaredAnnotations() { return AnnotationParser.toArray(declaredAnnotations()); }
/**
* Returns a string describing this record component. The format is
* the record component type, followed by a space, followed by the name
* of the record component.
* For example:
* <pre>
* String name
* int age
* </pre>
*
* @return a string describing this record component
*/
public String toString() {
return (getType().getTypeName() + " " + getName());
}
/**
* Returns the record class which declares this record component.
*
* @return The record class declaring this record component.
*/
public Class<?> getDeclaringRecord() {
return clazz;
}
}
