org.akubraproject.impl.AbstractBlobStoreConnection.java Source code

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Here is the source code for org.akubraproject.impl.AbstractBlobStoreConnection.java

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/* $HeadURL::                                                                            $
 * $Id$
 *
 * Copyright (c) 2009-2010 DuraSpace
 * http://duraspace.org
 *
 * In collaboration with Topaz Inc.
 * http://www.topazproject.org
 *
 * 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 org.akubraproject.impl;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Map;

import org.akubraproject.Blob;
import org.akubraproject.BlobStore;
import org.akubraproject.BlobStoreConnection;
import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * An abstract base class for blob store connections.
 *
 * @author Pradeep Krishnan
 */
public abstract class AbstractBlobStoreConnection implements BlobStoreConnection {
    private static final Logger log = LoggerFactory.getLogger(AbstractBlobStoreConnection.class);

    protected final BlobStore owner;
    protected final StreamManager streamManager;
    protected boolean closed = false;

    protected AbstractBlobStoreConnection(BlobStore owner) {
        this(owner, null);
    }

    protected AbstractBlobStoreConnection(BlobStore owner, StreamManager streamManager) {
        this.owner = owner;
        this.streamManager = streamManager;
    }

    @Override
    public BlobStore getBlobStore() {
        return owner;
    }

    @Override
    public Blob getBlob(InputStream content, long estimatedSize, Map<String, String> hints)
            throws IOException, UnsupportedOperationException {
        Blob blob = getBlob(null, hints);

        boolean success = false;
        try {
            OutputStream out = blob.openOutputStream(estimatedSize, true);
            try {
                IOUtils.copyLarge(content, out);
                out.close();
                out = null;
            } finally {
                if (out != null)
                    IOUtils.closeQuietly(out);
            }

            success = true;
        } finally {
            if (!success) {
                try {
                    blob.delete();
                } catch (Throwable t) {
                    log.error("Error deleting blob after blob-creation failure", t);
                }
            }
        }

        return blob;
    }

    @Override
    public void close() {
        if (!closed) {
            closed = true;
            if (streamManager != null)
                streamManager.connectionClosed(this);
        }
    }

    @Override
    public boolean isClosed() {
        return closed;
    }

    /**
     * Helper that checks whether the connection is open and throws an exception if not.
     *
     * @throws IllegalStateException if the connection has been closed
     */
    protected void ensureOpen() throws IllegalStateException {
        if (isClosed())
            throw new IllegalStateException("Connection closed.");
    }
}