org.pentaho.platform.repository.solution.dbbased.DbRepositoryClassLoader.java Source code

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Here is the source code for org.pentaho.platform.repository.solution.dbbased.DbRepositoryClassLoader.java

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/*
 * This program is free software; you can redistribute it and/or modify it under the 
 * terms of the GNU General Public License, version 2 as published by the Free Software 
 * Foundation.
 *
 * You should have received a copy of the GNU General Public License along with this 
 * program; if not, you can obtain a copy at http://www.gnu.org/licenses/gpl-2.0.html 
 * or from the Free Software Foundation, Inc., 
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * This program 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.
 *
 * 
 * Copyright 2006-2008 Pentaho Corporation.  All rights reserved. 
 * 
 * Created Mar 29, 2006 
 * @author wseyler
 */
package org.pentaho.platform.repository.solution.dbbased;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.pentaho.platform.api.repository.ISolutionRepository;
import org.pentaho.platform.repository.messages.Messages;
import org.pentaho.platform.repository.solution.SolutionRepositoryBase;

public class DbRepositoryClassLoader extends ClassLoader {
    protected static final Log logger = LogFactory.getLog(SolutionRepositoryBase.class);

    private static final HashMap resourceMap = new HashMap();

    String path;

    DbBasedSolutionRepository repository;

    public DbRepositoryClassLoader(final String inPath, final DbBasedSolutionRepository inRepository) {
        path = inPath;
        repository = inRepository;
    }

    /**
     * Returns the requested resource as an InputStream.
     * @param name The resource name
     * @retruns An input stream for reading the resource, or <code>null</code> if the resource could not be found 
     */
    @Override
    public InputStream getResourceAsStream(final String name) {
        String key = path + ISolutionRepository.SEPARATOR + name;
        byte[] bytes = (byte[]) DbRepositoryClassLoader.resourceMap.get(key);
        if (bytes == null) {
            try {
                bytes = repository.getResourceAsBytes(key, false, ISolutionRepository.ACTION_EXECUTE);
                DbRepositoryClassLoader.resourceMap.put(key, bytes);
            } catch (IOException ignored) {
                // This situation indicates the resource could not be found. This is a common and correct situation 
                // and this exception should be ignored.
                if (DbRepositoryClassLoader.logger.isTraceEnabled()) {
                    DbRepositoryClassLoader.logger
                            .trace(Messages.getString("DbRepositoryClassLoader.RESOURCE_NOT_FOUND", name)); //$NON-NLS-1$
                }

                // Return null to indicate that the resource could not be found (and this is ok) 
                return null;
            }
        }
        return new ByteArrayInputStream(bytes);
    }

    public static void clearResourceCache() {
        DbRepositoryClassLoader.resourceMap.clear();
    }

}