src/java/org/apache/commons/vfs/RandomAccessContent.java

/*
 * Copyright 2002-2005 The Apache Software Foundation.
 *
 * 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.apache.commons.vfs;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.InputStream;

/**
 * Description
 *
 * @author <a href="mailto:imario@apache.org">Mario Ivankovits</a>
 * @version $Revision$ $Date$
 */
public interface RandomAccessContent extends DataOutput, DataInput
{
    /**
     * Returns the current offset in this file.
     *
     * @return the offset from the beginning of the file, in bytes,
     *         at which the next read or write occurs.
     * @throws IOException if an I/O error occurs.
     */
    public long getFilePointer() throws IOException;

    /**
     * Sets the file-pointer offset, measured from the beginning of this
     * file, at which the next read or write occurs.  The offset may be
     * set beyond the end of the file. Setting the offset beyond the end
     * of the file does not change the file length.  The file length will
     * change only by writing after the offset has been set beyond the end
     * of the file.
     * <br/>
     * <b>Notice: If you use {@link #getInputStream()} you have to reget the InputStream after calling {@link #seek(long)}</b>
     *
     * @param pos the offset position, measured in bytes from the
     *            beginning of the file, at which to set the file
     *            pointer.
     * @throws IOException if <code>pos</code> is less than
     *                     <code>0</code> or if an I/O error occurs.
     */
    public void seek(long pos) throws IOException;

    /**
     * Returns the length of this file.
     *
     * @return the length of this file, measured in bytes.
     * @throws IOException if an I/O error occurs.
     */
    public long length() throws IOException;

    /**
     * Closes this random access file stream and releases any system
     * resources associated with the stream. A closed random access
     * file cannot perform input or output operations and cannot be
     * reopened.
     * <p/>
     * <p> If this file has an associated channel then the channel is closed
     * as well.
     *
     * @throws IOException if an I/O error occurs.
     */
    public void close() throws IOException;

    /**
     * get the inputstream interface
     * <br/>
     * <b>Notice: If you use {@link #seek(long)} you have to reget the InputStream</b>
     * @return
     */
    public InputStream getInputStream() throws IOException;
}