org.jclouds.vfs.provider.blobstore.BlobStoreRandomAccessContent.java Source code

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Here is the source code for org.jclouds.vfs.provider.blobstore.BlobStoreRandomAccessContent.java

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/**
 *
 * Copyright (C) 2010 Cloud Conscious, LLC. <info@cloudconscious.com>
 *
 * ====================================================================
 * 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.jclouds.vfs.provider.blobstore;

import java.io.DataInputStream;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;

import org.apache.commons.vfs.FileSystemException;
import org.apache.commons.vfs.provider.AbstractRandomAccessStreamContent;
import org.apache.commons.vfs.util.RandomAccessMode;
import org.jclouds.blobstore.options.GetOptions;

/**
 * @author Adrian Cole
 */
public class BlobStoreRandomAccessContent extends AbstractRandomAccessStreamContent {
    private final BlobStoreFileObject fileObject;

    protected long filePointer = 0;
    private DataInputStream dis = null;

    BlobStoreRandomAccessContent(final BlobStoreFileObject fileObject, RandomAccessMode mode) {
        super(mode);
        this.fileObject = fileObject;
    }

    public long getFilePointer() throws IOException {
        return filePointer;
    }

    public void seek(long pos) throws IOException {
        if (pos == filePointer) {
            // no change
            return;
        }

        if (pos < 0) {
            throw new FileSystemException("vfs.provider/random-access-invalid-position.error",
                    new Object[] { new Long(pos) });
        }
        if (dis != null) {
            close();
        }

        filePointer = pos;
    }

    protected DataInputStream getDataInputStream() throws IOException {
        if (dis != null) {
            return dis;
        }

        dis = new DataInputStream(
                new FilterInputStream((InputStream) fileObject.getBlobStore().getBlob(fileObject.getContainer(),
                        fileObject.getNameTrimLeadingSlashes(), new GetOptions().startAt(filePointer)).getPayload()
                        .getInput()) {
                    public int read() throws IOException {
                        int ret = super.read();
                        if (ret > -1) {
                            filePointer++;
                        }
                        return ret;
                    }

                    public int read(byte b[]) throws IOException {
                        int ret = super.read(b);
                        if (ret > -1) {
                            filePointer += ret;
                        }
                        return ret;
                    }

                    public int read(byte b[], int off, int len) throws IOException {
                        int ret = super.read(b, off, len);
                        if (ret > -1) {
                            filePointer += ret;
                        }
                        return ret;
                    }
                });

        return dis;
    }

    public void close() throws IOException {
        if (dis != null) {
            dis.close();
            dis = null;
        }
    }

    public long length() throws IOException {
        return fileObject.getContent().getSize();
    }
}