001: /*
002: * Copyright (c) 1998-2008 Caucho Technology -- all rights reserved
003: *
004: * This file is part of Resin(R) Open Source
005: *
006: * Each copy or derived work must preserve the copyright notice and this
007: * notice unmodified.
008: *
009: * Resin Open Source is free software; you can redistribute it and/or modify
010: * it under the terms of the GNU General Public License as published by
011: * the Free Software Foundation; either version 2 of the License, or
012: * (at your option) any later version.
013: *
014: * Resin Open Source is distributed in the hope that it will be useful,
015: * but WITHOUT ANY WARRANTY; without even the implied warranty of
016: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
017: * of NON-INFRINGEMENT. See the GNU General Public License for more
018: * details.
019: *
020: * You should have received a copy of the GNU General Public License
021: * along with Resin Open Source; if not, write to the
022: *
023: * Free Software Foundation, Inc.
024: * 59 Temple Place, Suite 330
025: * Boston, MA 02111-1307 USA
026: *
027: * @author Scott Ferguson
028: */
029:
030: package com.caucho.vfs;
031:
032: import java.io.IOException;
033: import java.io.InputStream;
034: import java.io.OutputStream;
035:
036: /**
037: * Reads from a file in a random-access fashion.
038: */
039: abstract public class RandomAccessStream implements LockableStream {
040: /**
041: * Returns the length.
042: */
043: abstract public long getLength() throws IOException;
044:
045: /**
046: * Reads a block starting from the current file pointer.
047: */
048: abstract public int read(byte[] buffer, int offset, int length)
049: throws IOException;
050:
051: /**
052: * Reads a block starting from the current file pointer.
053: */
054: abstract public int read(char[] buffer, int offset, int length)
055: throws IOException;
056:
057: /**
058: * Reads a block from a given location.
059: */
060: abstract public int read(long fileOffset, byte[] buffer,
061: int offset, int length) throws IOException;
062:
063: /**
064: * Writes a block starting from the current file pointer.
065: */
066: abstract public void write(byte[] buffer, int offset, int length)
067: throws IOException;
068:
069: /**
070: * Writes a block to a given location.
071: */
072: abstract public void write(long fileOffset, byte[] buffer,
073: int offset, int length) throws IOException;
074:
075: /**
076: * Seeks to the given position in the file.
077: */
078: abstract public boolean seek(long position);
079:
080: /**
081: * Returns an OutputStream for this stream.
082: */
083: abstract public OutputStream getOutputStream() throws IOException;
084:
085: /**
086: * Returns an InputStream for this stream.
087: */
088: abstract public InputStream getInputStream() throws IOException;
089:
090: /**
091: * Read a byte from the file, advancing the pointer.
092: */
093: abstract public int read() throws IOException;
094:
095: /**
096: * Write a byte to the file, advancing the pointer.
097: */
098: abstract public void write(int b) throws IOException;
099:
100: /**
101: * Returns the current position of the file pointer.
102: */
103: abstract public long getFilePointer() throws IOException;
104:
105: /**
106: * Closes the stream.
107: */
108: public void close() throws IOException {
109: }
110:
111: // Placeholder for LockableStream implementation
112:
113: public boolean lock(boolean shared, boolean block) {
114: return true;
115: }
116:
117: public boolean unlock() {
118: return true;
119: }
120: }
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