package org.oxerr.okcoin.rest.dto.valuereader;
   
   import java.io.IOException;
   import java.io.InputStream;
   import java.nio.charset.Charset;
   import java.nio.charset.StandardCharsets;
   import java.util.logging.Level;
   import java.util.logging.Logger;
   
  import javax.annotation.Nullable;
  
  import org.apache.commons.io.IOUtils;
  
  import com.fasterxml.jackson.core.type.TypeReference;
  import com.fasterxml.jackson.databind.JsonMappingException;
  import com.fasterxml.jackson.databind.ObjectMapper;
  
  public class JsonValueTypeRefReader<T> implements ValueReader<T> {
  
  	private final Logger log = Logger.getLogger(getClass().getName());
  
  	private final ObjectMapper objectMapper;
  
  	private final TypeReference<T> valueTypeRef;
  
  	public JsonValueTypeRefReader(ObjectMapper objectMapper,
  			TypeReference<T> valueTypeRef) {
  		this.objectMapper = objectMapper;
  		this.valueTypeRef = valueTypeRef;
  	}
  
  	/**
  	 * {@inheritDoc}
  	 */
  	@Override
  	public T read(InputStream inputStream,
  		@Nullable String mimeType, @Nullable Charset charset) throws IOException {
  		if (log.isLoggable(Level.FINEST)) {
  			inputStream = IOUtils.buffer(inputStream);
  			inputStream.mark(Integer.MAX_VALUE);
  			String s = IOUtils.toString(inputStream, charset != null ? charset : StandardCharsets.UTF_8);
  			log.log(Level.FINEST, "JSON: {0}", s);
  			inputStream.reset();
  		}
  		try {
  			return objectMapper.readValue(inputStream, valueTypeRef);
  		} catch (JsonMappingException jme) {
  			if (jme.getCause() instanceof RuntimeException) {
  				throw (RuntimeException) jme.getCause();
  			} else {
  				throw jme;
  			}
  		}
  	}
  
  }