Spring Source Analysis (i)

First, the analysis of the Aliasregistry interface.

1, alias aliases, Registry registry, Aliasregistry alias registry interface.

2, a total of four methods, register aliases, the name of the alias, get an array of aliases, remove aliases.

3, I myself tried to write an implementation class for this interface:

 Packagecom.lzh.spring.test;Importjava.util.ArrayList;Importjava.util.Hashtable;ImportJava.util.Iterator;Importjava.util.List;ImportJava.util.Map;ImportJava.util.Map.Entry;ImportOrg.springframework.core.AliasRegistry;/*** Implementation of the Alias registry interface *@authorLiaozhenghan * @date August 29, 2018*/ Public classMyaliasregistryImplementsaliasregistry{Privatemap<string, string> aliasmap =NewHashtable<>(); @Override Public voidRegisteralias (string name, string alias) {if(Isalias (alias)) {Throw Newillegalstateexception ();    } aliasmap.put (alias, name); } @Override Public voidRemovealias (String alias) {aliasmap.remove (alias); } @Override Public BooleanIsalias (String name) {returnAliasmap.containskey (name); } @Override Publicstring[] getaliases (String name) {List<String> aliases =NewArraylist<>(); Iterator<entry<string, string>> it =Aliasmap.entryset (). iterator (); Entry<string, string> entry =NULL;  while(It.hasnext ()) {entry=It.next (); if(Entry.getvalue (). Equals (name)) {Aliases.add (Entry.getkey ()); }} string[] array=Newstring[aliases.size ()]; returnAliases.toarray (array); }}

/** Copyright 2002-2012 the original author or authors. * Licensed under the Apache License, Version 2.0 (the "Licens E "); * You are not a use this file except in compliance with the License. * Obtain a copy of the License at * *http://www.apache.org/licenses/LICENSE-2.0* * Unless required by applicable or agreed to writing, software * Distributed under the License is distribute D on ' As is ' BASIS, * without warranties or CONDITIONS of any KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ PackageOrg.springframework.core;Importjava.util.ArrayList;ImportJava.util.HashMap;Importjava.util.List;ImportJava.util.Map;ImportJava.util.concurrent.ConcurrentHashMap;ImportOrg.springframework.util.Assert;Importorg.springframework.util.StringUtils;ImportOrg.springframework.util.StringValueResolver;/*** Simple Implementation of the {@linkAliasregistry} interface. * Serves as base class for * {@linkOrg.springframework.beans.factory.support.BeanDefinitionRegistry} * implementations. * * @authorJuergen Hoeller *@since2.5.2*/ Public classSimplealiasregistryImplementsAliasregistry {/**Map from alias to canonical name*/    Private Finalmap<string, string> aliasmap =NewConcurrenthashmap<string, String> (16); @Override Public voidRegisteralias (string name, string alias) {Assert.hastext (name,"' name ' must not be empty"); Assert.hastext (alias,"' Alias ' must not being empty"); if(alias.equals (name)) { This. Aliasmap.remove (alias); }        Else {            if(!allowaliasoverriding ()) {String Registeredname= This. Aliasmap.get (alias); if(Registeredname! =NULL&&!registeredname.equals (name)) {                    Throw NewIllegalStateException ("Cannot register alias" + alias + "' for Name '" +name+ "': It is already registered for name '" + Registeredname + "'.");            }} checkforaliascircle (name, alias);  This. Aliasmap.put (alias, name); }    }    /*** Return Whether alias overriding is allowed. * Default is {@codetrue}. */    protected Booleanallowaliasoverriding () {return true; } @Override Public voidRemovealias (String alias) {string name= This. Aliasmap.remove (alias); if(Name = =NULL) {            Throw NewIllegalStateException ("No alias" + alias + "' Registered"); }} @Override Public BooleanIsalias (String name) {return  This. Aliasmap.containskey (name); } @Override Publicstring[] getaliases (String name) {List<String> result =NewArraylist<string>(); synchronized( This. Aliasmap)        {retrievealiases (name, result); }        returnStringutils.tostringarray (Result); }    /*** transitively Retrieve all aliases for the given name. * @paramName the target name to find aliases for *@paramresult the resulting aliases list*/    Private voidRetrievealiases (String name, list<string>result) {         for(Map.entry<string, string> Entry: This. Aliasmap.entryset ()) {String Registeredname=Entry.getvalue (); if(registeredname.equals (name)) {String alias=Entry.getkey ();                Result.add (alias);            Retrievealiases (alias, result); }        }    }    /*** Resolve all alias target names and aliases registered in this * factory, applying the given Stringvaluereso     Lver to them.     * <p>the Value Resolver is example resolve placeholders * in target beans names and even in alias names. * @paramValueresolver the stringvalueresolver to apply*/     Public voidresolvealiases (Stringvalueresolver valueresolver) {assert.notnull (Valueresolver,"Stringvalueresolver must not being null"); synchronized( This. Aliasmap) {Map<string, string> aliascopy =NewHashmap<string, String> ( This. Aliasmap);  for(String Alias:aliasCopy.keySet ()) {string Registeredname=Aliascopy.get (alias); String Resolvedalias=Valueresolver.resolvestringvalue (alias); String Resolvedname=Valueresolver.resolvestringvalue (registeredname); if(Resolvedalias.equals (resolvedname)) { This. Aliasmap.remove (alias); }                Else if(!Resolvedalias.equals (alias)) {String ExistingName= This. Aliasmap.get (Resolvedalias); if(ExistingName! =NULL&&!existingname.equals (Resolvedname)) {                        Throw NewIllegalStateException ("Cannot register resolved alias '" + Resolvedalias + "' (Original: ' + alias + ') for Nam E ' "+ 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); }            }        }    }    /*** Determine the raw name, resolving aliases to canonical names. * @paramName the user-specified name *@returnThe transformed name*/     Publicstring CanonicalName (string name) {string CanonicalName=name; //Handle aliasing ...String Resolvedname;  Do{resolvedname= This. Aliasmap.get (CanonicalName); if(Resolvedname! =NULL) {canonicalname=Resolvedname; }        }         while(Resolvedname! =NULL); returncanonicalname; }    /*** Check Whether the given name points back to given alias as an alias * in the other direction, catching a CI     Rcular reference upfront and * throwing a corresponding illegalstateexception. * @paramName the candidate name *@paramAlias the candidate alias *@see#registerAlias*/    protected voidcheckforaliascircle (string name, string alias) {if(Alias.equals (canonicalname (name))) {Throw NewIllegalStateException ("Cannot register alias" + alias + "' for Name '" + Name + "': Circular referenc E-' "+name+ "is a direct or indirect alias for '" + Alias + "' Already"); }    }}

Spring Source Analysis (i)