com.moss.appsnap.keeper.data.jaxbstore.JaxbStore.java Source code

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Here is the source code for com.moss.appsnap.keeper.data.jaxbstore.JaxbStore.java

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/**
 * Copyright (C) 2013, Moss Computing Inc.
 *
 * This file is part of appsnap.
 *
 * appsnap is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * appsnap 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
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with appsnap; see the file COPYING.  If not, write to the
 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301 USA.
 *
 * Linking this library statically or dynamically with other modules is
 * making a combined work based on this library.  Thus, the terms and
 * conditions of the GNU General Public License cover the whole
 * combination.
 *
 * As a special exception, the copyright holders of this library give you
 * permission to link this library with independent modules to produce an
 * executable, regardless of the license terms of these independent
 * modules, and to copy and distribute the resulting executable under
 * terms of your choice, provided that you also meet, for each linked
 * independent module, the terms and conditions of the license of that
 * module.  An independent module is a module which is not derived from
 * or based on this library.  If you modify this library, you may extend
 * this exception to your version of the library, but you are not
 * obligated to do so.  If you do not wish to do so, delete this
 * exception statement from your version.
 */
package com.moss.appsnap.keeper.data.jaxbstore;

import java.io.File;
import java.io.FileFilter;
import java.io.IOException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.moss.jaxbhelper.JAXBHelper;

public abstract class JaxbStore<Id, T> {
    private final Log log = LogFactory.getLog(getClass());
    protected final File dataPath;
    private final JAXBHelper helper;

    public JaxbStore(File dataPath, JAXBHelper helper) throws IOException {
        super();
        this.dataPath = dataPath;
        this.helper = helper;

        preparePath();
    }

    protected void preparePath() throws IOException {
        if (!dataPath.exists() && !dataPath.mkdirs()) {
            throw new IOException("Could not create directory: " + dataPath.getAbsolutePath());
        }
    }

    protected abstract String fileName(Id id);

    protected File pathForId(Id id) {
        return new File(dataPath, fileName(id) + ".xml");
    }

    public T get(Id id) {
        final File path = pathForId(id);
        if (log.isDebugEnabled()) {
            log.debug("Getting from " + path.getAbsolutePath());
        }
        if (!path.exists()) {
            return null;
        } else {
            try {
                return (T) helper.readFromFile(path);
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        }
    }

    public void delete(Id id) {
        final File path = pathForId(id);
        if (log.isDebugEnabled()) {
            log.debug("Getting from " + path.getAbsolutePath());
        }
        if (!path.exists()) {
            throw new RuntimeException("No such item: " + id);
        } else {
            if (!path.delete()) {
                throw new RuntimeException("Could not delete file " + path.getAbsolutePath());
            }
        }
    }

    public void scan(ValueScanner<T> scanner) {
        File[] files = dataPath.listFiles(new FileFilter() {
            public boolean accept(File pathname) {
                return pathname.exists() && pathname.getName().endsWith(".xml");
            }
        });

        for (File next : files) {
            try {
                final boolean keepScanning = scanner.scan((T) helper.readFromFile(next));
                if (!keepScanning) {
                    return;
                }
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        }
    }

    public void put(Id id, T spec) {
        final File path = pathForId(id);
        try {
            helper.writeToFile(helper.writeToXmlString(spec), path);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}