org.xwiki.job.internal.xstream.SafeArrayConverter.java Source code

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Here is the source code for org.xwiki.job.internal.xstream.SafeArrayConverter.java

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/*
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.xwiki.job.internal.xstream;

import java.util.List;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.apache.commons.lang3.ClassUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Document;
import org.xwiki.component.annotation.Role;

import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.converters.MarshallingContext;
import com.thoughtworks.xstream.converters.UnmarshallingContext;
import com.thoughtworks.xstream.converters.collections.ArrayConverter;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
import com.thoughtworks.xstream.io.copy.HierarchicalStreamCopier;
import com.thoughtworks.xstream.io.xml.DomReader;
import com.thoughtworks.xstream.io.xml.DomWriter;
import com.thoughtworks.xstream.mapper.Mapper;

/**
 * Make sure to unzerialize as much as possible from the job status without failing.
 * 
 * @version $Id: e5332ad30223a6c5641e77de341c9925ff759662 $
 * @since 4.3M1
 */
public class SafeArrayConverter extends ArrayConverter {
    /**
     * The logger.
     */
    private static final Logger LOGGER = LoggerFactory.getLogger(SafeArrayConverter.class);

    private final DocumentBuilderFactory docFactory;

    private final DocumentBuilder docBuilder;

    private HierarchicalStreamCopier copier;

    private XStream xstream;

    /**
     * @param mapper the XStream mapper
     * @param xstream the {@link XStream} instance to use to isolate array element marshaling
     * @throws ParserConfigurationException when failing to create a {@link DocumentBuilder}
     */
    public SafeArrayConverter(Mapper mapper, XStream xstream) throws ParserConfigurationException {
        super(mapper);

        this.docFactory = DocumentBuilderFactory.newInstance();
        this.docBuilder = this.docFactory.newDocumentBuilder();
        this.copier = new HierarchicalStreamCopier();
        this.xstream = xstream;
    }

    @Override
    public boolean canConvert(Class type) {
        return type == Object[].class;
    }

    @Override
    protected Object readItem(HierarchicalStreamReader reader, UnmarshallingContext context, Object current) {
        Object value;
        try {
            value = super.readItem(reader, context, current);
        } catch (Throwable e) {
            LOGGER.debug("Failed to read field", e);

            value = null;
        }

        return value;
    }

    @Override
    protected void writeItem(Object item, MarshallingContext context, HierarchicalStreamWriter writer) {
        if (item == null || item instanceof String || item instanceof Number) {
            super.writeItem(item, context, writer);
        } else if (isComponent(item)) {
            super.writeItem(item.toString(), context, writer);
        } else {
            try {
                Document doc = this.docBuilder.newDocument();

                DomWriter domWriter = new DomWriter(doc);

                this.xstream.marshal(item, domWriter);

                DomReader domReader = new DomReader(doc);

                this.copier.copy(domReader, writer);
            } catch (Throwable e) {
                LOGGER.debug("Failed to write field", e);

                super.writeItem(item.toString(), context, writer);
            }
        }
    }

    /**
     * @param item the item to serialize
     * @return true of the item looks like a component
     */
    private boolean isComponent(Object item) {
        if (item != null) {
            List<Class<?>> interfaces = ClassUtils.getAllInterfaces(item.getClass());

            for (Class<?> iface : interfaces) {
                if (iface.isAnnotationPresent(Role.class)) {
                    return true;
                }
            }
        }

        return false;
    }
}