122 lines
4.3 KiB
Java
122 lines
4.3 KiB
Java
/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package javax.servlet;
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import java.io.IOException;
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import java.io.InputStream;
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/**
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* Provides an input stream for reading binary data from a client request,
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* including an efficient <code>readLine</code> method for reading data one line
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* at a time. With some protocols, such as HTTP POST and PUT, a
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* <code>ServletInputStream</code> object can be used to read data sent from the
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* client.
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* <p>
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* A <code>ServletInputStream</code> object is normally retrieved via the
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* {@link ServletRequest#getInputStream} method.
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* <p>
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* This is an abstract class that a servlet container implements. Subclasses of
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* this class must implement the <code>java.io.InputStream.read()</code> method.
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*
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* @see ServletRequest
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*/
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public abstract class ServletInputStream extends InputStream {
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/**
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* Does nothing, because this is an abstract class.
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*/
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protected ServletInputStream() {
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// NOOP
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}
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/**
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* Reads the input stream, one line at a time. Starting at an offset, reads
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* bytes into an array, until it reads a certain number of bytes or reaches
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* a newline character, which it reads into the array as well.
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* <p>
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* This method returns -1 if it reaches the end of the input stream before
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* reading the maximum number of bytes.
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*
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* @param b
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* an array of bytes into which data is read
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* @param off
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* an integer specifying the character at which this method
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* begins reading
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* @param len
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* an integer specifying the maximum number of bytes to read
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* @return an integer specifying the actual number of bytes read, or -1 if
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* the end of the stream is reached
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* @exception IOException
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* if an input or output exception has occurred
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*/
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public int readLine(byte[] b, int off, int len) throws IOException {
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if (len <= 0) {
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return 0;
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}
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int count = 0, c;
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while ((c = read()) != -1) {
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b[off++] = (byte) c;
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count++;
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if (c == '\n' || count == len) {
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break;
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}
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}
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return count > 0 ? count : -1;
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}
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/**
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* Has the end of this InputStream been reached?
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*
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* @return <code>true</code> if all the data has been read from the stream,
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* else <code>false</code>
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*
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* @since Servlet 3.1
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*/
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public abstract boolean isFinished();
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/**
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* Can data be read from this InputStream without blocking?
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* Returns If this method is called and returns false, the container will
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* invoke {@link ReadListener#onDataAvailable()} when data is available.
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*
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* @return <code>true</code> if data can be read without blocking, else
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* <code>false</code>
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*
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* @since Servlet 3.1
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*/
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public abstract boolean isReady();
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/**
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* Sets the {@link ReadListener} for this {@link ServletInputStream} and
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* thereby switches to non-blocking IO. It is only valid to switch to
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* non-blocking IO within async processing or HTTP upgrade processing.
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*
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* @param listener The non-blocking IO read listener
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*
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* @throws IllegalStateException If this method is called if neither
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* async nor HTTP upgrade is in progress or
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* if the {@link ReadListener} has already
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* been set
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* @throws NullPointerException If listener is null
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*
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* @since Servlet 3.1
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*/
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public abstract void setReadListener(ReadListener listener);
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}
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