Glassfish example source code file (LimitedInputStream.java)

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Java - Glassfish tags/keywords

filterinputstream, filterinputstream, io, ioexception, ioexception, limitedinputstream, limitedinputstream, sizeexception, sizeexception

The Glassfish LimitedInputStream.java source code

/*
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 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
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package org.apache.catalina.fileupload;

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


/**
 * An input stream, which limits its data size. This stream is
 * used, if the content length is unknown.
 */
abstract class LimitedInputStream
        extends FilterInputStream {
    /**
     * The maximum size of an item, in bytes.
     */
    private long sizeMax;
    /**
     * The current number of bytes.
     */
    private long count;
    /**
     * Whether this stream is already closed.
     */
    private boolean closed;

    /**
     * Creates a new instance.
     * @param pIn The input stream, which shall be limited.
     * @param pSizeMax The limit; no more than this number of bytes
     *   shall be returned by the source stream.
     */
    public LimitedInputStream(InputStream pIn, long pSizeMax) {
        super(pIn);
        sizeMax = pSizeMax;
    }

    /**
     * Called to indicate, that the input streams limit has
     * been exceeded.
     * @param pSizeMax The input streams limit, in bytes.
     * @param pCount The actual number of bytes.
     * @throws SizeException The called method is expected
     *   to raise an SizeException.
     */
    protected abstract void raiseError(long pSizeMax, long pCount)
            throws SizeException;

    /** Called to check, whether the input streams
     * limit is reached.
     * @throws SizeException The given limit is exceeded.
     */
    private void checkLimit() throws SizeException {
        if (count > sizeMax) {
            raiseError(sizeMax, count);
        }
    }

    /**
     * Reads the next byte of data from this input stream. The value
     * byte is returned as an <code>int in the range
     * <code>0 to 255. If no byte is available
     * because the end of the stream has been reached, the value
     * <code>-1 is returned. This method blocks until input data
     * is available, the end of the stream is detected, or an exception
     * is thrown.
     * <p>
     * This method
     * simply performs <code>in.read() and returns the result.
     *
     * @return     the next byte of data, or <code>-1 if the end of the
     *             stream is reached.
     * @exception  IOException  if an I/O error occurs.
     * @see        java.io.FilterInputStream#in
     */
    public int read() throws IOException {
        int res = super.read();
        if (res != -1) {
            count++;
            checkLimit();
        }
        return res;
    }

    /**
     * Reads up to <code>len bytes of data from this input stream
     * into an array of bytes. If <code>len is not zero, the method
     * blocks until some input is available; otherwise, no
     * bytes are read and <code>0 is returned.
     * <p>
     * This method simply performs <code>in.read(b, off, len)
     * and returns the result.
     *
     * @param      b     the buffer into which the data is read.
     * @param      off   The start offset in the destination array
     *                   <code>b.
     * @param      len   the maximum number of bytes read.
     * @return     the total number of bytes read into the buffer, or
     *             <code>-1 if there is no more data because the end of
     *             the stream has been reached.
     * @exception  NullPointerException If <code>b is null.
     * @exception  IndexOutOfBoundsException If <code>off is negative,
     * <code>len is negative, or len is greater than
     * <code>b.length - off
     * @exception  IOException  if an I/O error occurs.
     * @see        java.io.FilterInputStream#in
     */
    public int read(byte[] b, int off, int len) throws IOException {
        int res = super.read(b, off, len);
        if (res > 0) {
            count += res;
            checkLimit();
        }
        return res;
    }

    /**
     * Returns, whether this stream is already closed.
     * @return True, if the stream is closed, otherwise false.
     * @throws IOException An I/O error occurred.
     */
    public boolean isClosed() throws IOException {
        return closed;
    }

    /**
     * Closes this input stream and releases any system resources
     * associated with the stream.
     * This
     * method simply performs <code>in.close().
     *
     * @exception  IOException  if an I/O error occurs.
     * @see        java.io.FilterInputStream#in
     */
    public void close() throws IOException {
        closed = true;
        super.close();
    }
}