Apex, check object by Id.

Some times we need to know if Id matches the object we need. This method returns true, if matches:

public static Boolean isIdsObjectTypeEqualToStringObjectType( String objectIdString,
                                                              String objectTypeNameString ){
    Map<String, Schema.SObjectType> globalDescrideMap = Schema.getGlobalDescribe();    
    Boolean isEqual = false;
            
    Map<String,String> keyPrefixMap = new Map<String,String>{};

    for( String objectItem : globalDescrideMap.keySet() ){
       Schema.DescribeSObjectResult objectDescribe =  globalDescrideMap.get(objectItem).getDescribe();
       keyPrefixMap.put( objectDescribe.getKeyPrefix(), objectDescribe.getName() );
    }
    
    if( keyPrefixMap.get( objectIdString.subString( 0, 3 ) ) == objectTypeNameString ) isEqual = true;
    
    return isEqual;
}

Recommend to to move initialization of globalDescrideMap to top of class. And of course test:

@isTest( seeAllData = false ) private static void testIsIdsObjectTypeEqualToStringObjectType(){
    Integer NUMBER_TO_INSERT = 5;
    List<Account> testAccountList = new List<Account>();
    List<Boolean> testEqualsList = new List<Boolean>();
    List<Boolean> testNotEqualsList = new List<Boolean>();
    String accountObjectType = Account.getsObjectType().getDescribe().getName();
    
    for( Integer i = 0; NUMBER_TO_INSERT > i; i++ )
        testAccountList.add( TestingUtils.createTestAccount( null ) );
        
    insert testAccountList;
    
    Test.startTest();
        for( Account accountItem : testAccountList )
            testEqualsList.add( BluewolfDevUtils.isIdsObjectTypeEqualToStringObjectType( ( String )accountItem.Id, accountObjectType ) );
        
        for( Account accountItem : testAccountList )
            testNotEqualsList.add( BluewolfDevUtils.isIdsObjectTypeEqualToStringObjectType( ( String )accountItem.Id, 'Account__c' ) );
    Test.stopTest();
    
    for( Boolean testEqualsItem : testEqualsList )
        System.assertEquals( true, testEqualsItem );
    
    for( Boolean testNotEqualsItem : testNotEqualsList )
        System.assertEquals( false, testNotEqualsItem );
}

Enjoy.

UTD: New method.