129 lines
4.1 KiB
Java
129 lines
4.1 KiB
Java
package com.moparisthebest.phonehash;
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import java.io.FilterOutputStream;
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import java.io.IOException;
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import java.io.OutputStream;
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import java.util.Objects;
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/**
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* Created by mopar on 2/11/17.
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*/
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public class LockingBufferedOutputStream extends FilterOutputStream {
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/**
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* The internal buffer where data is stored.
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*/
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protected byte buf[];
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/**
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* The number of valid bytes in the buffer. This value is always
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* in the range <tt>0</tt> through <tt>buf.length</tt>; elements
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* <tt>buf[0]</tt> through <tt>buf[count-1]</tt> contain valid
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* byte data.
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*/
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protected int count;
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protected final Object lock;
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/**
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* Creates a new buffered output stream to write data to the
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* specified underlying output stream.
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*
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* @param out the underlying output stream.
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*/
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public LockingBufferedOutputStream(OutputStream out, final Object lock) {
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this(out, lock, 8192);
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}
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/**
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* Creates a new buffered output stream to write data to the
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* specified underlying output stream with the specified buffer
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* size.
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*
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* @param out the underlying output stream.
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* @param size the buffer size.
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* @exception IllegalArgumentException if size <= 0.
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*/
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public LockingBufferedOutputStream(OutputStream out, final Object lock, int size) {
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super(out);
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Objects.requireNonNull(lock);
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if (size <= 0) {
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throw new IllegalArgumentException("Buffer size <= 0");
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}
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buf = new byte[size];
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this.lock = lock;
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}
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/** Flush the internal buffer */
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private void flushBuffer() throws IOException {
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if (count > 0) {
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out.write(buf, 0, count);
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count = 0;
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}
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}
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/**
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* Writes the specified byte to this buffered output stream.
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*
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* @param b the byte to be written.
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* @exception IOException if an I/O error occurs.
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*/
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public synchronized void write(int b) throws IOException {
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if (count >= buf.length) {
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synchronized (lock) {
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flushBuffer();
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}
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}
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buf[count++] = (byte)b;
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}
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/**
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* Writes <code>len</code> bytes from the specified byte array
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* starting at offset <code>off</code> to this buffered output stream.
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*
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* <p> Ordinarily this method stores bytes from the given array into this
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* stream's buffer, flushing the buffer to the underlying output stream as
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* needed. If the requested length is at least as large as this stream's
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* buffer, however, then this method will flush the buffer and write the
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* bytes directly to the underlying output stream. Thus redundant
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* <code>BufferedOutputStream</code>s will not copy data unnecessarily.
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*
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* @param b the data.
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* @param off the start offset in the data.
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* @param len the number of bytes to write.
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* @exception IOException if an I/O error occurs.
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*/
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public synchronized void write(byte b[], int off, int len) throws IOException {
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if (len >= buf.length) {
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/* If the request length exceeds the size of the output buffer,
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flush the output buffer and then write the data directly.
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In this way buffered streams will cascade harmlessly. */
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synchronized (lock) {
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flushBuffer();
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out.write(b, off, len);
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}
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return;
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}
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if (len > buf.length - count) {
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synchronized (lock) {
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flushBuffer();
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}
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}
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System.arraycopy(b, off, buf, count, len);
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count += len;
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}
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/**
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* Flushes this buffered output stream. This forces any buffered
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* output bytes to be written out to the underlying output stream.
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*
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* @exception IOException if an I/O error occurs.
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* @see java.io.FilterOutputStream#out
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*/
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public synchronized void flush() throws IOException {
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synchronized (lock) {
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flushBuffer();
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out.flush();
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}
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}
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}
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