mirror of https://github.com/postgres/postgres
Tue Jan 30 22:24:00 GMT 2001 peter@retep.org.uk
- Fixed bug where Statement.setMaxRows() was a global setting. Now
limited to just itself.
- Changed LargeObject.read(byte[],int,int) to return the actual number
of bytes read (used to be void).
- LargeObject now supports InputStream's!
- PreparedStatement.setBinaryStream() now works!
- ResultSet.getBinaryStream() now returns an InputStream that doesn't
copy the blob into memory first!
- Connection.isClosed() now tests to see if the connection is still alive
rather than if it thinks it's alive.
REL7_1_STABLE
Peter Mount
25 years ago
parent
dca0762efc
commit
8439a83d84
@ -0,0 +1,156 @@ |
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package org.postgresql.largeobject; |
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|
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import java.io.InputStream; |
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import java.io.IOException; |
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import java.sql.SQLException; |
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|
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/** |
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* This is an initial implementation of an InputStream from a large object. |
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* For now, the bare minimum is implemented. Later (after 7.1) we will overide |
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* the other read methods to optimise them. |
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*/ |
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public class BlobInputStream extends InputStream { |
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/** |
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* The parent LargeObject |
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*/ |
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private LargeObject lo; |
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|
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/** |
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* Buffer used to improve performance |
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*/ |
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private byte[] buffer; |
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/** |
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* Position within buffer |
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*/ |
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private int bpos; |
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|
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/** |
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* The buffer size |
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*/ |
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private int bsize; |
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|
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/** |
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* The mark position |
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*/ |
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private int mpos=0; |
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|
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/** |
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* @param lo LargeObject to read from |
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*/ |
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public BlobInputStream(LargeObject lo) { |
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this(lo,1024); |
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} |
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|
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/** |
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* @param lo LargeObject to read from |
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* @param bsize buffer size |
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*/ |
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public BlobInputStream(LargeObject lo,int bsize) { |
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this.lo=lo; |
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buffer=null; |
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bpos=0; |
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this.bsize=bsize; |
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} |
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|
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/** |
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* The minimum required to implement input stream |
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*/ |
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public int read() throws java.io.IOException { |
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try { |
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if(buffer==null || bpos>=buffer.length) { |
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buffer=lo.read(bsize); |
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bpos=0; |
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} |
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|
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// Handle EOF
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if(bpos>=buffer.length) |
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return -1; |
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return (int) buffer[bpos++]; |
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} catch(SQLException se) { |
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throw new IOException(se.toString()); |
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} |
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} |
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|
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/** |
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* Closes this input stream and releases any system resources associated |
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* with the stream. |
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* |
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* <p> The <code>close</code> method of <code>InputStream</code> does |
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* nothing. |
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* |
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* @exception IOException if an I/O error occurs. |
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*/ |
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public void close() throws IOException { |
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try { |
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lo.close(); |
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lo=null; |
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} catch(SQLException se) { |
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throw new IOException(se.toString()); |
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} |
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} |
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|
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/** |
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* Marks the current position in this input stream. A subsequent call to |
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* the <code>reset</code> method repositions this stream at the last marked |
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* position so that subsequent reads re-read the same bytes. |
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* |
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* <p> The <code>readlimit</code> arguments tells this input stream to |
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* allow that many bytes to be read before the mark position gets |
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* invalidated. |
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* |
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* <p> The general contract of <code>mark</code> is that, if the method |
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* <code>markSupported</code> returns <code>true</code>, the stream somehow |
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* remembers all the bytes read after the call to <code>mark</code> and |
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* stands ready to supply those same bytes again if and whenever the method |
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* <code>reset</code> is called. However, the stream is not required to |
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* remember any data at all if more than <code>readlimit</code> bytes are |
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* read from the stream before <code>reset</code> is called. |
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* |
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* <p> The <code>mark</code> method of <code>InputStream</code> does |
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* nothing. |
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* |
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* @param readlimit the maximum limit of bytes that can be read before |
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* the mark position becomes invalid. |
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* @see java.io.InputStream#reset() |
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*/ |
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public synchronized void mark(int readlimit) { |
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try { |
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mpos=lo.tell(); |
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} catch(SQLException se) { |
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//throw new IOException(se.toString());
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} |
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} |
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|
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/** |
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* Repositions this stream to the position at the time the |
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* <code>mark</code> method was last called on this input stream. |
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* NB: If mark is not called we move to the begining. |
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* @see java.io.InputStream#mark(int) |
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* @see java.io.IOException |
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*/ |
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public synchronized void reset() throws IOException { |
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try { |
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lo.seek(mpos); |
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} catch(SQLException se) { |
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throw new IOException(se.toString()); |
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} |
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} |
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|
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/** |
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* Tests if this input stream supports the <code>mark</code> and |
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* <code>reset</code> methods. The <code>markSupported</code> method of |
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* <code>InputStream</code> returns <code>false</code>. |
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* |
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* @return <code>true</code> if this true type supports the mark and reset |
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* method; <code>false</code> otherwise. |
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* @see java.io.InputStream#mark(int) |
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* @see java.io.InputStream#reset() |
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*/ |
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public boolean markSupported() { |
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return true; |
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} |
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} |
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@ -0,0 +1,102 @@ |
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package org.postgresql.largeobject; |
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import java.io.IOException; |
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import java.io.OutputStream; |
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import java.sql.SQLException; |
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/** |
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* This implements a basic output stream that writes to a LargeObject |
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*/ |
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public class BlobOutputStream extends OutputStream { |
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/** |
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* The parent LargeObject |
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*/ |
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private LargeObject lo; |
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/** |
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* Buffer |
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*/ |
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private byte buf[]; |
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/** |
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* Size of the buffer (default 1K) |
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*/ |
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private int bsize; |
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/** |
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* Position within the buffer |
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*/ |
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private int bpos; |
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/** |
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* Create an OutputStream to a large object |
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* @param lo LargeObject |
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*/ |
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public BlobOutputStream(LargeObject lo) { |
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this(lo,1024); |
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} |
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|
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/** |
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* Create an OutputStream to a large object |
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* @param lo LargeObject |
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* @param bsize The size of the buffer used to improve performance |
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*/ |
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public BlobOutputStream(LargeObject lo,int bsize) { |
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this.lo=lo; |
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this.bsize=bsize; |
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buf=new byte[bsize]; |
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bpos=0; |
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} |
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public void write(int b) throws java.io.IOException { |
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try { |
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if(bpos>=bsize) { |
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lo.write(buf); |
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bpos=0; |
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} |
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buf[bpos++]=(byte)b; |
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} catch(SQLException se) { |
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throw new IOException(se.toString()); |
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} |
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} |
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/** |
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* Flushes this output stream and forces any buffered output bytes |
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* to be written out. The general contract of <code>flush</code> is |
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* that calling it is an indication that, if any bytes previously |
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* written have been buffered by the implementation of the output |
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* stream, such bytes should immediately be written to their |
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* intended destination. |
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* |
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* @exception IOException if an I/O error occurs. |
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*/ |
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public void flush() throws IOException { |
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try { |
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if(bpos>0) |
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lo.write(buf,0,bpos); |
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bpos=0; |
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} catch(SQLException se) { |
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throw new IOException(se.toString()); |
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} |
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} |
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/** |
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* Closes this output stream and releases any system resources |
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* associated with this stream. The general contract of <code>close</code> |
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* is that it closes the output stream. A closed stream cannot perform |
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* output operations and cannot be reopened. |
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* <p> |
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* The <code>close</code> method of <code>OutputStream</code> does nothing. |
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* |
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* @exception IOException if an I/O error occurs. |
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*/ |
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public void close() throws IOException { |
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try { |
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lo.close(); |
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lo=null; |
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} catch(SQLException se) { |
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throw new IOException(se.toString()); |
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} |
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} |
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|
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} |
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