java.lang.Object

java.lang.Record

cloud.opencode.base.web.cache.ETag

Record Components:: value - the opaque tag value (without quotes) | 不含引号的标签值; weak - whether this is a weak ETag | 是否为弱 ETag

public record ETag(String value, boolean weak) extends Record

HTTP ETag (Entity Tag) generation and matching HTTP ETag（实体标签）生成与匹配

Provides ETag creation, parsing, and comparison following RFC 7232 semantics, including strong and weak comparison functions.

提供 ETag 创建、解析和比较功能，遵循 RFC 7232 语义，包括强比较和弱比较函数。

Features | 主要功能:

Strong and weak ETag creation - 强/弱 ETag 创建
Content-based ETag generation (SHA-256) - 基于内容的 ETag 生成（SHA-256）
If-None-Match header matching (multi-value, wildcard) - If-None-Match 头部匹配
Strong and weak comparison functions per RFC 7232 - RFC 7232 强/弱比较函数

Usage Examples | 使用示例:

// Create ETags
ETag strong = ETag.strong("abc123");
ETag weak = ETag.weak("abc123");
ETag fromContent = ETag.fromContent("Hello, World!");

// Parse from header
ETag parsed = ETag.parse("W/\"abc123\"");

// Match against If-None-Match
boolean match = etag.matches("\"abc123\", W/\"def456\"");

// Comparison
boolean strongMatch = etag1.strongMatches(etag2);
boolean weakMatch = etag1.weakMatches(etag2);

Security | 安全性:

Thread-safe: Yes (immutable record) - 线程安全: 是（不可变记录）
Null-safe: Yes (factory methods reject null) - 空值安全: 是（工厂方法拒绝 null）

Since:

JDK 25, opencode-base-web V1.0.3

Author:

Leon Soo www.LeonSoo.com

See Also:

Constructor Summary

Constructors

Constructor

Description

ETag(String value, boolean weak)

Compact constructor: validates that value is not null or empty.
Method Summary

Modifier and Type

Method

Description

final boolean

equals(Object o)

Indicates whether some other object is "equal to" this one.

static ETag

fromContent(byte[] content)

Create a strong ETag from content bytes using SHA-256 digest.

static ETag

fromContent(String content)

Create a strong ETag from content string using SHA-256 digest (UTF-8).

final int

hashCode()

Returns a hash code value for this object.

String

headerValue()

Return the ETag header value (e.g., "abc" or W/"abc").

boolean

matches(String ifNoneMatch)

Check if this ETag matches an If-None-Match header value.

static ETag

parse(String headerValue)

Parse an ETag header value (e.g., "abc" or W/"abc").

static ETag

strong(String value)

Create a strong ETag.

boolean

strongMatches(ETag other)

Strong comparison function (RFC 7232 Section 2.3.2).

String

toString()

Returns the header value representation.

String

value()

Returns the value of the value record component.

boolean

weak()

Returns the value of the weak record component.

static ETag

weak(String value)

Create a weak ETag.

boolean

weakMatches(ETag other)

Weak comparison function (RFC 7232 Section 2.3.2).

Methods inherited from class Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Details
- ETag
  
  public ETag(String value, boolean weak)
  
  Compact constructor: validates that value is not null or empty. 紧凑构造器：验证 value 不为 null 且不为空。
Method Details
- strong
  
  public static ETag strong(String value)
  
  Create a strong ETag. 创建强 ETag。
  
  Parameters:
  
  value - the tag value | 标签值
  
  Returns:
  
  the strong ETag | 强 ETag
- weak
  
  public static ETag weak(String value)
  
  Create a weak ETag. 创建弱 ETag。
  
  Parameters:
  
  value - the tag value | 标签值
  
  Returns:
  
  the weak ETag | 弱 ETag
- fromContent
  
  public static ETag fromContent(byte[] content)
  
  Create a strong ETag from content bytes using SHA-256 digest. 使用 SHA-256 摘要从内容字节创建强 ETag。
  
  Parameters:
  
  content - the content bytes | 内容字节
  
  Returns:
  
  the strong ETag with hex digest value | 使用十六进制摘要值的强 ETag
  
  Throws:
  
  NullPointerException - if content is null | 如果内容为 null
- fromContent
  
  public static ETag fromContent(String content)
  
  Create a strong ETag from content string using SHA-256 digest (UTF-8). 使用 SHA-256 摘要从内容字符串创建强 ETag（UTF-8）。
  
  Parameters:
  
  content - the content string | 内容字符串
  
  Returns:
  
  the strong ETag with hex digest value | 使用十六进制摘要值的强 ETag
  
  Throws:
  
  NullPointerException - if content is null | 如果内容为 null
- parse
  
  public static ETag parse(String headerValue)
  
  Parse an ETag header value (e.g., "abc" or W/"abc"). 解析 ETag 头部值。
  
  Parameters:
  
  headerValue - the header value | 头部值
  
  Returns:
  
  the parsed ETag | 解析后的 ETag
  
  Throws:
  
  IllegalArgumentException - if the header value is malformed | 如果头部值格式错误
- headerValue
  
  public String headerValue()
  
  Return the ETag header value (e.g., "abc" or W/"abc"). 返回 ETag 头部值。
  
  Returns:
  
  the header value | 头部值
- matches
  
  public boolean matches(String ifNoneMatch)
  
  Check if this ETag matches an If-None-Match header value. 检查此 ETag 是否匹配 If-None-Match 头部值。
  Supports wildcard ("*") and comma-separated multi-value headers. Uses weak comparison as defined in RFC 7232 Section 3.2.
  
  Parameters:
  
  ifNoneMatch - the If-None-Match header value | If-None-Match 头部值
  
  Returns:
  
  true if this ETag matches | 如果匹配返回 true
- strongMatches
  
  public boolean strongMatches(ETag other)
  
  Strong comparison function (RFC 7232 Section 2.3.2). 强比较函数（RFC 7232 第 2.3.2 节）。
  Both ETags must be strong (not weak) and have the same opaque-tag value.
  
  Parameters:
  
  other - the other ETag | 另一个 ETag
  
  Returns:
  
  true if both are strong and equal | 如果两者都是强且相等返回 true
- weakMatches
  
  public boolean weakMatches(ETag other)
  
  Weak comparison function (RFC 7232 Section 2.3.2). 弱比较函数（RFC 7232 第 2.3.2 节）。
  Only the opaque-tag values need to match; weakness is ignored.
  
  Parameters:
  
  other - the other ETag | 另一个 ETag
  
  Returns:
  
  true if values are equal (ignoring weakness) | 如果值相等（忽略弱标记）返回 true
- toString
  
  public String toString()
  
  Returns the header value representation. 返回头部值表示。
  
  Specified by:
  
  toString in class Record
  
  Returns:
  
  the header value | 头部值
- hashCode
  
  public final int hashCode()
  
  Returns a hash code value for this object. The value is derived from the hash code of each of the record components.
  
  Specified by:
  
  hashCode in class Record
  
  Returns:
  
  a hash code value for this object
- equals
  
  public final boolean equals(Object o)
  
  Indicates whether some other object is "equal to" this one. The objects are equal if the other object is of the same class and if all the record components are equal. Reference components are compared with Objects::equals(Object,Object); primitive components are compared with the compare method from their corresponding wrapper classes.
  
  Specified by:
  
  equals in class Record
  
  Parameters:
  
  o - the object with which to compare
  
  Returns:
  
  true if this object is the same as the o argument; false otherwise.
- value
  
  public String value()
  
  Returns the value of the value record component.
  
  Returns:
  
  the value of the value record component
- weak
  
  public boolean weak()
  
  Returns the value of the weak record component.
  
  Returns:
  
  the value of the weak record component

Record Class ETag

Constructor Summary

Method Summary

Methods inherited from class Object

Constructor Details

ETag

Method Details

strong

weak

fromContent

fromContent

parse

headerValue

matches

strongMatches

weakMatches

toString

hashCode

equals

value

weak