io.rtr.alchemy.service.exceptions.RuntimeExceptionMapper Maven / Gradle / Ivy

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package io.rtr.alchemy.service.exceptions;

import com.google.common.collect.Maps;

import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import javax.ws.rs.ext.ExceptionMapper;
import java.util.Map;

/**
 * Maps common runtime exceptions to their respective HTTP status codes
 */
public class RuntimeExceptionMapper implements ExceptionMapper {
    private static final Map, Response.Status> EXCEPTION_MAPPINGS;

    static {
        EXCEPTION_MAPPINGS = Maps.newLinkedHashMap();

        // 400 - Bad Request
        register(Response.Status.BAD_REQUEST,
            IllegalArgumentException.class,
            IllegalStateException.class,
            NullPointerException.class
        );
    }

    private static void register(Response.Status status, Class ... types) {
        for (Class type : types) {
            EXCEPTION_MAPPINGS.put(type, status);
        }
    }

    @Override
    public Response toResponse(RuntimeException e) {
        if (e instanceof WebApplicationException) {
            return ((WebApplicationException) e).getResponse();
        }

        final Response.Status status = EXCEPTION_MAPPINGS.get(e.getClass());

        if (status == null) {
            throw new WebApplicationException(e);
        }

        return Response
                .status(status)
                .type(MediaType.APPLICATION_JSON)
                .entity(e.getMessage())
                .build();
    }
}