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From mamaco <mam...@163.com>
Subject Option meta schema in cache level?
Date Sun, 21 Jan 2018 20:27:05 GMT
I'm trying to use Binary Marshaller to replace old OptimizedMarshaller which
is really a pain for deployment.
But according to document of Type Metadata, it could be changed at runtime,
that means if I access to a 3rd party cache which was created by someone
else without explicit type settings, I'll have to get a sample row to
retrieve its type manually prior to further operations. is this correct? why
not just set a default optional meta type in cache level? as an option, it
won't be negative for dynamic row schema.



#access to a cache 'SQL_PUBLIC_CITY' (created by JDBC 'Create Table'
statement) and do some normal operations.
#GetSchema() is weird

public class App 
{
	private static SchemaType schema=null;
    public static void main( String[] args )
    {
    	Ignite ignite =
Ignition.start("C://apache//ignite//apache-ignite-fabric-2.2.0-bin//config//client.xml");
  	
    	CacheConfiguration<BinaryObject, BinaryObject> cfg = new
CacheConfiguration<BinaryObject, BinaryObject>("SQL_PUBLIC_CITY");
    	IgniteCache<BinaryObject, BinaryObject> cache =
ignite.getOrCreateCache(cfg).withKeepBinary();
    	
    	if(schema==null) schema=GetSchema(cache);
    	Put(ignite,cache,4L,"Los Angeles");
    	GetAll(cache);
    	Get(ignite,cache,4L);
    	Query(cache,4L);
    	ignite.close();
    }
    
    public static void GetAll(IgniteCache<BinaryObject, BinaryObject> cache)
{
    	Iterator<Cache.Entry&lt;BinaryObject, BinaryObject>>  itr =
cache.iterator();
    	while(itr.hasNext()){
    		Cache.Entry<BinaryObject, BinaryObject> item = itr.next();
    		System.out.println("id="+item.getKey().field("id")+" 
KeyType="+item.getKey().type().typeName().toString()+" 
V="+item.getKey().type().field("id"));
    		System.out.println("CITY="+item.getValue().field("name")+ "  of
id="+item.getValue().field("id"));
    	}
    }
    
    public static SchemaType GetSchema(IgniteCache<BinaryObject,
BinaryObject> cache) {
    	SchemaType sch=new SchemaType();
		Cache.Entry<BinaryObject, BinaryObject> item = cache.iterator().next();
		sch.KeyType=item.getKey().type().typeName();
		sch.KeyFields=item.getKey().type().fieldNames();
		sch.ValueType=item.getValue().type().typeName();
		sch.ValueFields=item.getValue().type().fieldNames();
    	return sch;
    }
    
    
    
    public static void Get(Ignite ignite, IgniteCache<BinaryObject,
BinaryObject> cache, Long CityId) {
        BinaryObjectBuilder keyBuilder =
ignite.binary().builder(schema.KeyType)
                .setField("id", CityId);
        
        BinaryObject value = cache.get(keyBuilder.build());
    	if(value!=null) System.out.println("CITY="+value.field("name"));
    }
    
    public static void Put(Ignite ignite, IgniteCache<BinaryObject,
BinaryObject> cache,Long CityId,String CityName) {
        BinaryObjectBuilder keyBuilder =
ignite.binary().builder(schema.KeyType)
                .setField("id", CityId);
        BinaryObjectBuilder valueBuilder =
ignite.binary().builder(schema.ValueType)
                .setField("name", CityName);
        
        cache.put(keyBuilder.build(),valueBuilder.build());
    }
    
    public static void Query(IgniteCache<BinaryObject, BinaryObject> cache,
Long CityId) {
        QueryCursor<List&lt;?>> query = cache.query(new
SqlFieldsQuery("select * from City where id="+CityId));
        System.out.println(query.getAll());
    }
}






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