--- /dev/null
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package javax.servlet;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * Provides an input stream for reading binary data from a client request,
+ * including an efficient <code>readLine</code> method for reading data one line
+ * at a time. With some protocols, such as HTTP POST and PUT, a
+ * <code>ServletInputStream</code> object can be used to read data sent from the
+ * client.
+ * <p>
+ * A <code>ServletInputStream</code> object is normally retrieved via the
+ * {@link ServletRequest#getInputStream} method.
+ * <p>
+ * This is an abstract class that a servlet container implements. Subclasses of
+ * this class must implement the <code>java.io.InputStream.read()</code> method.
+ *
+ * @see ServletRequest
+ */
+public abstract class ServletInputStream extends InputStream {
+
+ /**
+ * Does nothing, because this is an abstract class.
+ */
+ protected ServletInputStream() {
+ // NOOP
+ }
+
+ /**
+ * Reads the input stream, one line at a time. Starting at an offset, reads
+ * bytes into an array, until it reads a certain number of bytes or reaches
+ * a newline character, which it reads into the array as well.
+ * <p>
+ * This method returns -1 if it reaches the end of the input stream before
+ * reading the maximum number of bytes.
+ *
+ * @param b
+ * an array of bytes into which data is read
+ * @param off
+ * an integer specifying the character at which this method
+ * begins reading
+ * @param len
+ * an integer specifying the maximum number of bytes to read
+ * @return an integer specifying the actual number of bytes read, or -1 if
+ * the end of the stream is reached
+ * @exception IOException
+ * if an input or output exception has occurred
+ */
+ public int readLine(byte[] b, int off, int len) throws IOException {
+
+ if (len <= 0) {
+ return 0;
+ }
+ int count = 0, c;
+
+ while ((c = read()) != -1) {
+ b[off++] = (byte) c;
+ count++;
+ if (c == '\n' || count == len) {
+ break;
+ }
+ }
+ return count > 0 ? count : -1;
+ }
+
+ /**
+ * Returns <code>true</code> if all the data has been read from the stream,
+ * else <code>false</code>.
+ *
+ * @since Servlet 3.1
+ */
+ public abstract boolean isFinished();
+
+ /**
+ * Returns <code>true</code> if data can be read without blocking, else
+ * <code>false</code>. If this method is called and returns false, the
+ * container will invoke {@link ReadListener#onDataAvailable()} when data is
+ * available.
+ *
+ * @since Servlet 3.1
+ */
+ public abstract boolean isReady();
+
+ /**
+ * Sets the {@link ReadListener} for this {@link ServletInputStream} and
+ * thereby switches to non-blocking IO. It is only valid to switch to
+ * non-blocking IO within async processing or HTTP upgrade processing.
+ *
+ * @param listener The non-blocking IO read listener
+ *
+ * @throws IllegalStateException If this method is called if neither
+ * async nor HTTP upgrade is in progress or
+ * if the {@link ReadListener} has already
+ * been set
+ * @throws NullPointerException If listener is null
+ *
+ * @since Servlet 3.1
+ */
+ public abstract void setReadListener(ReadListener listener);
+}