| /* |
| * 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 org.apache.sling.servlets.get.impl.helpers; |
| |
| import java.io.PrintWriter; |
| import java.io.Writer; |
| |
| import javax.servlet.ServletOutputStream; |
| import javax.servlet.WriteListener; |
| |
| import org.apache.sling.api.SlingHttpServletResponse; |
| import org.apache.sling.api.wrappers.SlingHttpServletResponseWrapper; |
| |
| /** |
| * The <code>HeadServletResponse</code> is a Sling response wrapper which |
| * ensures that nothing will ever be written by return null writers or output |
| * streams. |
| */ |
| |
| public class HeadServletResponse extends SlingHttpServletResponseWrapper { |
| |
| private ServletOutputStream stream; |
| |
| private PrintWriter writer; |
| |
| public HeadServletResponse(SlingHttpServletResponse wrappedResponse) { |
| super(wrappedResponse); |
| } |
| |
| @Override |
| public ServletOutputStream getOutputStream() { |
| if (writer != null) { |
| throw new IllegalStateException("Writer already obtained"); |
| } |
| |
| if (stream == null) { |
| stream = new NullServletOutputStream(); |
| } |
| |
| return stream; |
| } |
| |
| @Override |
| public PrintWriter getWriter() { |
| if (stream != null) { |
| throw new IllegalStateException("OutputStream already obtained"); |
| } |
| |
| if (writer == null) { |
| writer = new PrintWriter(new NullWriter()); |
| } |
| |
| return writer; |
| } |
| |
| /** |
| * The <code>NullServletOutputStream</code> is a |
| * <code>ServletOutputStream</code> which simply does not write out anything. |
| * |
| * @see HeadServletResponse#getOutputStream() |
| */ |
| private static class NullServletOutputStream extends ServletOutputStream { |
| @Override |
| public void write(int b) { |
| } |
| |
| @Override |
| public void write(byte[] b) { |
| } |
| |
| @Override |
| public void write(byte[] b, int off, int len) { |
| } |
| |
| @Override |
| public boolean isReady() { |
| return true; |
| } |
| |
| @Override |
| public void setWriteListener(WriteListener writeListener) { |
| } |
| } |
| |
| /** |
| * The <code>NullWriter</code> is a <code>Writer</code> which simply does not |
| * write out anything. |
| * |
| * @see HeadServletResponse#getWriter() |
| */ |
| private static class NullWriter extends Writer { |
| @Override |
| public void write(char[] cbuf, int off, int len) { |
| } |
| |
| @Override |
| public void write(char[] cbuf) { |
| } |
| |
| @Override |
| public void write(int c) { |
| } |
| |
| @Override |
| public void write(String str) { |
| } |
| |
| @Override |
| public void write(String str, int off, int len) { |
| } |
| |
| @Override |
| public void flush() { |
| } |
| |
| @Override |
| public void close() { |
| } |
| } |
| } |