package org.oxerr.commons.ws.rs.provider;
   
   import java.lang.annotation.Annotation;
   import java.lang.reflect.Type;
   
   import javax.inject.Singleton;
   import javax.ws.rs.ext.ParamConverter;
   import javax.ws.rs.ext.ParamConverterProvider;
   import javax.ws.rs.ext.Provider;
  
  /**
   * {@code ParamConverterProvider} for converting between a {@code String} and
   * {@link Character}.
   */
  @Provider
  @Singleton
  public class CharacterProvider implements ParamConverterProvider {
  
  	/**
  	 * {@inheritDoc}
  	 */
  	@Override
  	public <T> ParamConverter<T> getConverter(Class<T> rawType,
  			Type genericType, Annotation[] annotations) {
  		return (rawType != Character.class) ? null : new ParamConverter<T>() {
  
  			@Override
  			public T fromString(final String value) {
  				if (value == null) {
  					throw new IllegalArgumentException("value cannot be null");
  				}
  
  				final T ret;
  				if (value.isEmpty()) {
  					ret = null;
  				} else {
  					ret = rawType.cast(Character.valueOf(value.charAt(0)));
  				}
  
  				return ret;
  			}
  
  			@Override
  			public String toString(final T value)
  					throws IllegalArgumentException {
  				if (value == null) {
  					throw new IllegalArgumentException("value cannot be null.");
  				}
  				return value.toString();
  			}
  		};
  	}
  
  }