edu.utah.further.core.cxf.ResponseWsExceptionMapper.java Source code

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Here is the source code for edu.utah.further.core.cxf.ResponseWsExceptionMapper.java

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/**
 * Copyright (C) [2013] [The FURTHeR Project]
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package edu.utah.further.core.cxf;

import static org.slf4j.LoggerFactory.getLogger;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.ws.rs.core.Response;
import javax.ws.rs.ext.Provider;

import org.apache.commons.lang.StringUtils;
import org.apache.cxf.jaxrs.client.ResponseExceptionMapper;
import org.slf4j.Logger;

import edu.utah.further.core.api.constant.ErrorCode;
import edu.utah.further.core.api.exception.ApplicationError;
import edu.utah.further.core.api.exception.WsException;
import edu.utah.further.core.api.lang.ReflectionUtil;
import edu.utah.further.core.api.xml.XmlService;
import edu.utah.further.core.util.io.IoUtil;

/**
 * A {@link WsException} CXF unmarshaller.
 * <p>
 * -----------------------------------------------------------------------------------<br>
 * (c) 2008-2010 FURTHeR Project, AVP Health Sciences IT Office, University of Utah<br>
 * Contact: {@code <further@utah.edu>}<br>
 * Biomedical Informatics, 26 South 2000 East<br>
 * Room 5775 HSEB, Salt Lake City, UT 84112<br>
 * Day Phone: 1-801-581-4080<br>
 * -----------------------------------------------------------------------------------
 *
 * @author Oren E. Livne {@code <oren.livne@utah.edu>}
 * @version Feb 25, 2009
 */
@Provider
public class ResponseWsExceptionMapper implements ResponseExceptionMapper<WsException> {
    // ========================= FIELDS ====================================

    /**
     * A logger that helps identify this class' printouts.
     */
    private static final Logger log = getLogger(ResponseWsExceptionMapper.class);

    // ========================= DEPENEDNCIES ==============================

    /**
     * Executes JAXB utilities. Injected + lazily initialized via a service locator
     * pattern and a double-locking singleton pattern.
     */
    private volatile XmlService xmlService;

    // ========================= IMPLEMENTATION: ExceptionMapper ===========

    /**
     * @param r
     * @return
     * @see org.apache.cxf.jaxrs.client.ResponseExceptionMapper#fromResponse(javax.ws.rs.core.Response)
     */
    @SuppressWarnings("resource")
    // is is closed in finally block
    @Override
    public WsException fromResponse(final Response r) {
        if (log.isDebugEnabled()) {
            log.debug("Mapping r " + r);
        }

        InputStream is = null;
        try {
            is = getResponseInputStream(r);
            if (is.markSupported()) {
                // FUR-1331: if we can create a string copy of the input stream, check if
                // it's empty and protected against unmarshalled exceptions
                final ByteArrayOutputStream copy = IoUtil.copyInputStream(is);
                final String errorXml = new String(copy.toByteArray());
                copy.close();
                if (log.isDebugEnabled()) {
                    log.debug("Error XML:" + errorXml);
                }
                if (StringUtils.isBlank(errorXml)) {
                    return new WsException(ErrorCode.INTERNAL_ERROR,
                            "An error without an explicit message has occurred");
                }
            }
            final ApplicationError error = getXmlService().unmarshal(is, ApplicationError.class);
            return new WsException(error);
        } catch (final Throwable e) {
            return new WsException(ErrorCode.INTERNAL_ERROR, "Failed to unmarshal exception from XML: ", e);
        } finally {
            try {
                if (is != null) {
                    is.close();
                }
            } catch (final IOException e) {
                e.printStackTrace();
            }
        }
    }

    // ========================= PRIVATE METHODS ===========================

    /**
     * @param r
     * @return
     */
    private InputStream getResponseInputStream(final Response r) {
        final Object entity = r.getEntity();
        return (ReflectionUtil.instanceOf(entity, String.class))
                ? new ByteArrayInputStream(((String) entity).getBytes())
                : (InputStream) entity;
    }

    /**
     * Return the xmlService property.
     *
     * @return the xmlService
     */
    public XmlService getXmlService() {
        // using the double-checked locking with volatile
        // @see http://www.cs.umd.edu/~pugh/java/memoryModel/DoubleCheckedLocking.html
        if (xmlService == null) {
            synchronized (this) {
                if (xmlService == null) {
                    xmlService = CoreCxfResourceLocator.getInstance().getXmlService();
                }
            }
        }
        return xmlService;
    }
}