相关源码注释
Spring 5 SimpleAliasRegistry 源码注释 Spring 5 DefaultSingletonBeanRegistry 源码注释 Spring 5 FactoryBeanRegistrySupport 源码注释 Spring 5 AbstractBeanFactory 源码注释 Spring 5 AbstractAutowireCapableBeanFactory 源码注释 Spring 5 DefaultLisbaleBeanFactory 源码注释
UML类图
源码
public class SimpleAliasRegistry implements AliasRegistry {
protected final Log logger
= LogFactory
.getLog(getClass());
private final Map
<String, String> aliasMap
= new ConcurrentHashMap<>(16);
@Override
public void registerAlias(String name
, String alias
) {
Assert
.hasText(name
, "'name' must not be empty");
Assert
.hasText(alias
, "'alias' must not be empty");
synchronized (this.aliasMap
) {
if (alias
.equals(name
)) {
this.aliasMap
.remove(alias
);
if (logger
.isDebugEnabled()) {
logger
.debug("Alias definition '" + alias
+ "' ignored since it points to same name");
}
}
else {
String registeredName
= this.aliasMap
.get(alias
);
if (registeredName
!= null
) {
if (registeredName
.equals(name
)) {
return;
}
if (!allowAliasOverriding()) {
throw new IllegalStateException("Cannot define alias '" + alias
+ "' for name '" +
name
+ "': It is already registered for name '" + registeredName
+ "'.");
}
if (logger
.isDebugEnabled()) {
logger
.debug("Overriding alias '" + alias
+ "' definition for registered name '" +
registeredName
+ "' with new target name '" + name
+ "'");
}
}
checkForAliasCircle(name
, alias
);
this.aliasMap
.put(alias
, name
);
if (logger
.isTraceEnabled()) {
logger
.trace("Alias definition '" + alias
+ "' registered for name '" + name
+ "'");
}
}
}
}
protected boolean allowAliasOverriding() {
return true;
}
public boolean hasAlias(String name
, String alias
) {
for (Map
.Entry
<String, String> entry
: this.aliasMap
.entrySet()) {
String registeredName
= entry
.getValue();
if (registeredName
.equals(name
)) {
String registeredAlias
= entry
.getKey();
if (registeredAlias
.equals(alias
) || hasAlias(registeredAlias
, alias
)) {
return true;
}
}
}
return false;
}
@Override
public void removeAlias(String alias
) {
synchronized (this.aliasMap
) {
String name
= this.aliasMap
.remove(alias
);
if (name
== null
) {
throw new IllegalStateException("No alias '" + alias
+ "' registered");
}
}
}
@Override
public boolean isAlias(String name
) {
return this.aliasMap
.containsKey(name
);
}
@Override
public String
[] getAliases(String name
) {
List
<String> result
= new ArrayList<>();
synchronized (this.aliasMap
) {
retrieveAliases(name
, result
);
}
return StringUtils
.toStringArray(result
);
}
private void retrieveAliases(String name
, List
<String> result
) {
this.aliasMap
.forEach((alias
, registeredName
) -> {
if (registeredName
.equals(name
)) {
result
.add(alias
);
retrieveAliases(alias
, result
);
}
});
}
public void resolveAliases(StringValueResolver valueResolver
) {
Assert
.notNull(valueResolver
, "StringValueResolver must not be null");
synchronized (this.aliasMap
) {
Map
<String, String> aliasCopy
= new HashMap<>(this.aliasMap
);
aliasCopy
.forEach((alias
, registeredName
) -> {
String resolvedAlias
= valueResolver
.resolveStringValue(alias
);
String resolvedName
= valueResolver
.resolveStringValue(registeredName
);
if (resolvedAlias
== null
|| resolvedName
== null
|| resolvedAlias
.equals(resolvedName
)) {
this.aliasMap
.remove(alias
);
}
else if (!resolvedAlias
.equals(alias
)) {
String existingName
= this.aliasMap
.get(resolvedAlias
);
if (existingName
!= null
) {
if (existingName
.equals(resolvedName
)) {
this.aliasMap
.remove(alias
);
return;
}
throw new IllegalStateException(
"Cannot register resolved alias '" + resolvedAlias
+ "' (original: '" + alias
+
"') for name '" + resolvedName
+ "': It is already registered for name '" +
registeredName
+ "'.");
}
checkForAliasCircle(resolvedName
, resolvedAlias
);
this.aliasMap
.remove(alias
);
this.aliasMap
.put(resolvedAlias
, resolvedName
);
}
else if (!registeredName
.equals(resolvedName
)) {
this.aliasMap
.put(alias
, resolvedName
);
}
});
}
}
protected void checkForAliasCircle(String name
, String alias
) {
if (hasAlias(alias
, name
)) {
throw new IllegalStateException("Cannot register alias '" + alias
+
"' for name '" + name
+ "': Circular reference - '" +
name
+ "' is a direct or indirect alias for '" + alias
+ "' already");
}
}
public String
canonicalName(String name
) {
String canonicalName
= name
;
String resolvedName
;
do {
resolvedName
= this.aliasMap
.get(canonicalName
);
if (resolvedName
!= null
) {
canonicalName
= resolvedName
;
}
}
while (resolvedName
!= null
);
return canonicalName
;
}
}
