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 * Copyright 2014 Red Hat, Inc., and individual contributors
 * as indicated by the @author tags.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
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 *  distributed under the License is distributed on an "AS IS" BASIS,
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 *  See the License for the specific language governing permissions and
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package io.undertow.servlet.spec;

import javax.servlet.DispatcherType;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.CoderResult;
import java.nio.charset.CodingErrorAction;
import java.util.Locale;

Real servlet print writer functionality, that is not limited by extending PrintWriter

Author:Stuart Douglas
/** * Real servlet print writer functionality, that is not limited by extending * {@link java.io.PrintWriter} * <p> * * @author Stuart Douglas */
public class ServletPrintWriter { private static final char[] EMPTY_CHAR = {}; private final ServletOutputStreamImpl outputStream; private final String charset; private CharsetEncoder charsetEncoder; private boolean error = false; private boolean closed = false; private char[] underflow; public ServletPrintWriter(final ServletOutputStreamImpl outputStream, final String charset) throws UnsupportedEncodingException { this.charset = charset; this.outputStream = outputStream; //for some known charset we get optimistic and hope that //only ascii will be output //in this case we can avoid creating the encoder altogether if (!charset.equalsIgnoreCase("utf-8") && !charset.equalsIgnoreCase("iso-8859-1")) { createEncoder(); } } private void createEncoder() { this.charsetEncoder = Charset.forName(this.charset).newEncoder(); //replace malformed and unmappable with question marks this.charsetEncoder.onUnmappableCharacter(CodingErrorAction.REPLACE); this.charsetEncoder.onMalformedInput(CodingErrorAction.REPLACE); } public void flush() { try { outputStream.flush(); } catch (IOException e) { error = true; } } public void close() { if (outputStream.getServletRequestContext().getOriginalRequest().getDispatcherType() == DispatcherType.INCLUDE) { return; } if (closed) { return; } closed = true; try { boolean done = false; CharBuffer buffer; if (underflow == null) { buffer = CharBuffer.wrap(EMPTY_CHAR); } else { buffer = CharBuffer.wrap(underflow); underflow = null; } if (charsetEncoder != null) { do { ByteBuffer out = outputStream.underlyingBuffer(); if (out == null) { //servlet output stream has already been closed error = true; return; } CoderResult result = charsetEncoder.encode(buffer, out, true); if (result.isOverflow()) { outputStream.flushInternal(); if (out.remaining() == 0) { outputStream.close(); error = true; return; } } else { done = true; } } while (!done); } outputStream.close(); } catch (IOException e) { error = true; } } public boolean checkError() { flush(); return error; } public void write(final CharBuffer input) { ByteBuffer buffer = outputStream.underlyingBuffer(); if (buffer == null) { //stream has been closed error = true; return; } try { if (!buffer.hasRemaining()) { outputStream.flushInternal(); if (!buffer.hasRemaining()) { error = true; return; } } if (charsetEncoder == null) { createEncoder(); } final CharBuffer cb; if (underflow == null) { cb = input; } else { char[] newArray = new char[underflow.length + input.remaining()]; System.arraycopy(underflow, 0, newArray, 0, underflow.length); input.get(newArray, underflow.length, input.remaining()); cb = CharBuffer.wrap(newArray); underflow = null; } int last = -1; while (cb.hasRemaining()) { int remaining = buffer.remaining(); CoderResult result = charsetEncoder.encode(cb, buffer, false); outputStream.updateWritten(remaining - buffer.remaining()); if (result.isOverflow() || !buffer.hasRemaining()) { outputStream.flushInternal(); if (!buffer.hasRemaining()) { error = true; return; } } if (result.isUnderflow()) { underflow = new char[cb.remaining()]; cb.get(underflow); return; } if (result.isError()) { error = true; return; } if (result.isUnmappable()) { //this should not happen error = true; return; } if (last == cb.remaining()) { underflow = new char[cb.remaining()]; cb.get(underflow); return; } last = cb.remaining(); } } catch (IOException e) { error = true; } } public void write(final int c) { write(Character.toString((char)c)); } public void write(final char[] buf, final int off, final int len) { if(charsetEncoder == null) { try { ByteBuffer buffer = outputStream.underlyingBuffer(); if(buffer == null) { //already closed error = true; return; } //fast path, basically we are hoping this is ascii only int remaining = buffer.remaining(); boolean ok = true; //so we have a pure ascii buffer, just write it out and skip all the encoder cost int end = off + len; int i = off; int flushPos = i + remaining; while (ok && i < end) { int realEnd = Math.min(end, flushPos); for (; i < realEnd; ++i) { char c = buf[i]; if (c > 127) { ok = false; break; } else { buffer.put((byte) c); } } if (i == flushPos) { outputStream.flushInternal(); flushPos = i + buffer.remaining(); } } outputStream.updateWritten(remaining - buffer.remaining()); if (ok) { return; } final CharBuffer cb = CharBuffer.wrap(buf, i, len - (i - off)); write(cb); return; } catch (IOException e) { error = false; return; } } final CharBuffer cb = CharBuffer.wrap(buf, off, len); write(cb); } public void write(final char[] buf) { write(buf,0, buf.length); } public void write(final String s, final int off, final int len) { if(charsetEncoder == null) { try { ByteBuffer buffer = outputStream.underlyingBuffer(); if(buffer == null) { //already closed error = true; return; } //fast path, basically we are hoping this is ascii only int remaining = buffer.remaining(); boolean ok = true; //so we have a pure ascii buffer, just write it out and skip all the encoder cost int end = off + len; int i = off; int fpos = i + remaining; for (; i < end; ++i) { if (i == fpos) { outputStream.flushInternal(); fpos = i + buffer.remaining(); } char c = s.charAt(i); if (c > 127) { ok = false; break; } buffer.put((byte) c); } outputStream.updateWritten(remaining - buffer.remaining()); if (ok) { return; } //wrap(String, off, len) acts wrong in the presence of multi byte characters final CharBuffer cb = CharBuffer.wrap(s.toCharArray(), i, len - (i - off)); write(cb); return; } catch (IOException e) { error = false; return; } } final CharBuffer cb = CharBuffer.wrap(s, off, off + len); write(cb); } public void write(final String s) { write(s, 0, s.length()); } public void print(final boolean b) { write(Boolean.toString(b)); } public void print(final char c) { write(Character.toString(c)); } public void print(final int i) { write(Integer.toString(i)); } public void print(final long l) { write(Long.toString(l)); } public void print(final float f) { write(Float.toString(f)); } public void print(final double d) { write(Double.toString(d)); } public void print(final char[] s) { write(CharBuffer.wrap(s)); } public void print(final String s) { write(s == null ? "null" : s); } public void print(final Object obj) { write(obj == null ? "null" : obj.toString()); } public void println() { print("\r\n"); } public void println(final boolean b) { print(b); println(); } public void println(final char c) { print(c); println(); } public void println(final int i) { print(i); println(); } public void println(final long l) { print(l); println(); } public void println(final float f) { print(f); println(); } public void println(final double d) { print(d); println(); } public void println(final char[] s) { print(s); println(); } public void println(final String s) { print(s); println(); } public void println(final Object obj) { print(obj); println(); } public void printf(final String format, final Object... args) { print(String.format(format, args)); } public void printf(final Locale l, final String format, final Object... args) { print(String.format(l, format, args)); } public void format(final String format, final Object... args) { printf(format, args); } public void format(final Locale l, final String format, final Object... args) { printf(l, format, args); } public void append(final CharSequence csq) { if (csq == null) { write("null"); } else { write(csq.toString()); } } public void append(final CharSequence csq, final int start, final int end) { CharSequence cs = (csq == null ? "null" : csq); write(cs.subSequence(start, end).toString()); } public void append(final char c) { write(c); } }