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package com.sun.xml.internal.ws.util;

import com.sun.istack.internal.NotNull;
import com.sun.istack.internal.Nullable;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.logging.Level;
import java.util.logging.Logger;

Reads a input stream completely and creates a new stream by keeping some data in memory and the rest on the file system.
Author:Jitendra Kotamraju
/** * Reads a input stream completely and creates a new stream * by keeping some data in memory and the rest on the file system. * * @author Jitendra Kotamraju */
public class ReadAllStream extends InputStream { private final @NotNull MemoryStream memStream; private final @NotNull FileStream fileStream; private boolean readAll; private boolean closed; private static final Logger LOGGER = Logger.getLogger(ReadAllStream.class.getName()); public ReadAllStream() { memStream = new MemoryStream(); fileStream = new FileStream(); }
Reads the data from input stream completely. It keeps inMemory size in the memory, and the rest on the file system. Caller's responsibility to close the InputStream. This method can be called only once.
Params:
  • in – from which to be read
  • inMemory – this much data is kept in the memory
Throws:
/** * Reads the data from input stream completely. It keeps * inMemory size in the memory, and the rest on the file * system. * * Caller's responsibility to close the InputStream. This * method can be called only once. * * @param in from which to be read * @param inMemory this much data is kept in the memory * @throws IOException in case of exception */
public void readAll(InputStream in, long inMemory) throws IOException { assert !readAll; readAll = true; boolean eof = memStream.readAll(in, inMemory); if (!eof) { fileStream.readAll(in); } } @Override public int read() throws IOException { int ch = memStream.read(); if (ch == -1) { ch = fileStream.read(); } return ch; } @Override public int read(byte b[], int off, int sz) throws IOException { int len = memStream.read(b, off, sz); if (len == -1) { len = fileStream.read(b, off, sz); } return len; } @Override public void close() throws IOException { if (!closed) { memStream.close(); fileStream.close(); closed = true; } } // Keeps the rest of the data on the file system private static class FileStream extends InputStream { private @Nullable File tempFile; private @Nullable FileInputStream fin; void readAll(InputStream in) throws IOException { tempFile = File.createTempFile("jaxws",".bin"); FileOutputStream fileOut = new FileOutputStream(tempFile); try { byte[] buf = new byte[8192]; int len; while((len=in.read(buf)) != -1) { fileOut.write(buf, 0, len); } } finally { fileOut.close(); } fin = new FileInputStream(tempFile); } @Override public int read() throws IOException { return (fin != null) ? fin.read() : -1; } @Override public int read(byte b[], int off, int sz) throws IOException { return (fin != null) ? fin.read(b, off, sz) : -1; } @Override public void close() throws IOException { if (fin != null) { fin.close(); } if (tempFile != null) { boolean success = tempFile.delete(); if (!success) { LOGGER.log(Level.INFO, "File {0} could not be deleted", tempFile); } } } } // Keeps data in memory until certain size private static class MemoryStream extends InputStream { private Chunk head, tail; private int curOff; private void add(byte[] buf, int len) { if (tail != null) { tail = tail.createNext(buf, 0, len); } else { head = tail = new Chunk(buf, 0, len); } }
Reads until the size specified
Params:
  • in – stream from which to be read
  • inMemory – reads until this size
Throws:
Returns:true if eof false otherwise
/** * Reads until the size specified * * @param in stream from which to be read * @param inMemory reads until this size * @return true if eof * false otherwise * @throws IOException in case of exception */
boolean readAll(InputStream in, long inMemory) throws IOException { long total = 0; while(true) { byte[] buf = new byte[8192]; int read = fill(in, buf); total += read; if (read != 0) { add(buf, read); } if (read != buf.length) { return true; } // EOF if (total > inMemory) { return false; // Reached in-memory size } } } private int fill(InputStream in, byte[] buf) throws IOException { int read; int total = 0; while(total < buf.length && (read=in.read(buf, total, buf.length-total)) != -1) { total += read; } return total; } @Override public int read() throws IOException { if (!fetch()) { return -1; } return (head.buf[curOff++] & 0xff); } @Override public int read(byte b[], int off, int sz) throws IOException { if (!fetch()) { return -1; } sz = Math.min(sz, head.len-(curOff-head.off)); System.arraycopy(head.buf,curOff,b,off,sz); curOff += sz; return sz; } // if eof, return false else true private boolean fetch() { if (head == null) { return false; } if (curOff == head.off+head.len) { head = head.next; if (head == null) { return false; } curOff = head.off; } return true; } private static final class Chunk { Chunk next; final byte[] buf; final int off; final int len; public Chunk(byte[] buf, int off, int len) { this.buf = buf; this.off = off; this.len = len; } public Chunk createNext(byte[] buf, int off, int len) { return next = new Chunk(buf, off, len); } } } }