Java tutorial
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See the License for the * specific language governing permissions and limitations * under the License. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * */ package org.apache.http.impl.nio.reactor; import java.io.IOException; import java.nio.ByteBuffer; import java.nio.CharBuffer; import java.nio.channels.ReadableByteChannel; import java.nio.channels.WritableByteChannel; import java.nio.charset.CharacterCodingException; import java.nio.charset.Charset; import java.nio.charset.CharsetDecoder; import java.nio.charset.CoderResult; import org.apache.http.nio.reactor.SessionInputBuffer; import org.apache.http.nio.util.ByteBufferAllocator; import org.apache.http.nio.util.ExpandableBuffer; import org.apache.http.nio.util.HeapByteBufferAllocator; import org.apache.http.params.HttpParams; import org.apache.http.params.HttpProtocolParams; import org.apache.http.protocol.HTTP; import org.apache.http.util.CharArrayBuffer; /** * Default implementation of {@link SessionInputBuffer} based on * the {@link ExpandableBuffer} class. * <p> * The following parameters can be used to customize the behavior of this * class: * <ul> * <li>{@link org.apache.http.params.CoreProtocolPNames#HTTP_ELEMENT_CHARSET}</li> * </ul> * * @since 4.0 */ public class SessionInputBufferImpl extends ExpandableBuffer implements SessionInputBuffer { private CharBuffer charbuffer = null; private Charset charset = null; private CharsetDecoder chardecoder = null; public SessionInputBufferImpl(int buffersize, int linebuffersize, final ByteBufferAllocator allocator, final HttpParams params) { super(buffersize, allocator); this.charbuffer = CharBuffer.allocate(linebuffersize); this.charset = Charset.forName(HttpProtocolParams.getHttpElementCharset(params)); this.chardecoder = this.charset.newDecoder(); } public SessionInputBufferImpl(int buffersize, int linebuffersize, final HttpParams params) { this(buffersize, linebuffersize, new HeapByteBufferAllocator(), params); } public int fill(final ReadableByteChannel channel) throws IOException { if (channel == null) { throw new IllegalArgumentException("Channel may not be null"); } setInputMode(); if (!this.buffer.hasRemaining()) { expand(); } int readNo = channel.read(this.buffer); return readNo; } public int read() { setOutputMode(); return this.buffer.get() & 0xff; } public int read(final ByteBuffer dst, int maxLen) { if (dst == null) { return 0; } setOutputMode(); int len = Math.min(dst.remaining(), maxLen); int chunk = Math.min(this.buffer.remaining(), len); for (int i = 0; i < chunk; i++) { dst.put(this.buffer.get()); } return chunk; } public int read(final ByteBuffer dst) { if (dst == null) { return 0; } return read(dst, dst.remaining()); } public int read(final WritableByteChannel dst, int maxLen) throws IOException { if (dst == null) { return 0; } setOutputMode(); int bytesRead; if (this.buffer.remaining() > maxLen) { int oldLimit = this.buffer.limit(); int newLimit = oldLimit - (this.buffer.remaining() - maxLen); this.buffer.limit(newLimit); bytesRead = dst.write(this.buffer); this.buffer.limit(oldLimit); } else { bytesRead = dst.write(this.buffer); } return bytesRead; } public int read(final WritableByteChannel dst) throws IOException { if (dst == null) { return 0; } setOutputMode(); return dst.write(this.buffer); } public boolean readLine(final CharArrayBuffer linebuffer, boolean endOfStream) throws CharacterCodingException { setOutputMode(); // See if there is LF char present in the buffer int pos = -1; boolean hasLine = false; for (int i = this.buffer.position(); i < this.buffer.limit(); i++) { int b = this.buffer.get(i); if (b == HTTP.LF) { hasLine = true; pos = i + 1; break; } } if (!hasLine) { if (endOfStream && this.buffer.hasRemaining()) { // No more data. Get the rest pos = this.buffer.limit(); } else { // Either no complete line present in the buffer // or no more data is expected return false; } } int origLimit = this.buffer.limit(); this.buffer.limit(pos); int len = this.buffer.limit() - this.buffer.position(); // Ensure capacity of len assuming ASCII as the most likely charset linebuffer.ensureCapacity(len); this.chardecoder.reset(); for (;;) { CoderResult result = this.chardecoder.decode(this.buffer, this.charbuffer, true); if (result.isError()) { result.throwException(); } if (result.isOverflow()) { this.charbuffer.flip(); linebuffer.append(this.charbuffer.array(), this.charbuffer.position(), this.charbuffer.remaining()); this.charbuffer.clear(); } if (result.isUnderflow()) { break; } } this.buffer.limit(origLimit); // flush the decoder this.chardecoder.flush(this.charbuffer); this.charbuffer.flip(); // append the decoded content to the line buffer if (this.charbuffer.hasRemaining()) { linebuffer.append(this.charbuffer.array(), this.charbuffer.position(), this.charbuffer.remaining()); } // discard LF if found int l = linebuffer.length(); if (l > 0) { if (linebuffer.charAt(l - 1) == HTTP.LF) { l--; linebuffer.setLength(l); } // discard CR if found if (l > 0) { if (linebuffer.charAt(l - 1) == HTTP.CR) { l--; linebuffer.setLength(l); } } } return true; } public String readLine(boolean endOfStream) throws CharacterCodingException { CharArrayBuffer charbuffer = new CharArrayBuffer(64); boolean found = readLine(charbuffer, endOfStream); if (found) { return charbuffer.toString(); } else { return null; } } }