Java tutorial
/* * Copyright 2002-2012 the original author or authors. * * 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 * * 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.springframework.session.web; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import javax.servlet.ServletOutputStream; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpServletResponseWrapper; import java.io.IOException; import java.io.PrintWriter; import java.util.Locale; /** * Base class for response wrappers which encapsulate the logic for handling an event when the * {@link javax.servlet.http.HttpServletResponse} is committed. * * @author Rob Winch */ abstract class OnCommittedResponseWrapper extends HttpServletResponseWrapper { private final Log logger = LogFactory.getLog(getClass()); private boolean disableOnCommitted; /** * @param response the response to be wrapped */ public OnCommittedResponseWrapper(HttpServletResponse response) { super(response); } /** * Invoke this method to disable invoking {@link OnCommittedResponseWrapper#onResponseCommitted()} when the {@link javax.servlet.http.HttpServletResponse} is * committed. This can be useful in the event that Async Web Requests are * made. */ public void disableOnResponseCommitted() { this.disableOnCommitted = true; } /** * Implement the logic for handling the {@link javax.servlet.http.HttpServletResponse} being committed */ protected abstract void onResponseCommitted(); /** * Makes sure {@link OnCommittedResponseWrapper#onResponseCommitted()} is invoked before calling the * superclass <code>sendError()</code> */ @Override public final void sendError(int sc) throws IOException { doOnResponseCommitted(); super.sendError(sc); } /** * Makes sure {@link OnCommittedResponseWrapper#onResponseCommitted()} is invoked before calling the * superclass <code>sendError()</code> */ @Override public final void sendError(int sc, String msg) throws IOException { doOnResponseCommitted(); super.sendError(sc, msg); } /** * Makes sure {@link OnCommittedResponseWrapper#onResponseCommitted()} is invoked before calling the * superclass <code>sendRedirect()</code> */ @Override public final void sendRedirect(String location) throws IOException { doOnResponseCommitted(); super.sendRedirect(location); } /** * Makes sure {@link OnCommittedResponseWrapper#onResponseCommitted()} is invoked before calling the calling * <code>getOutputStream().close()</code> or <code>getOutputStream().flush()</code> */ @Override public ServletOutputStream getOutputStream() throws IOException { return new SaveContextServletOutputStream(super.getOutputStream()); } /** * Makes sure {@link OnCommittedResponseWrapper#onResponseCommitted()} is invoked before calling the * <code>getWriter().close()</code> or <code>getWriter().flush()</code> */ @Override public PrintWriter getWriter() throws IOException { return new SaveContextPrintWriter(super.getWriter()); } /** * Makes sure {@link OnCommittedResponseWrapper#onResponseCommitted()} is invoked before calling the * superclass <code>flushBuffer()</code> */ @Override public void flushBuffer() throws IOException { doOnResponseCommitted(); super.flushBuffer(); } /** * Calls <code>onResponseCommmitted()</code> with the current contents as long as * {@link #disableOnResponseCommitted()()} was not invoked. */ private void doOnResponseCommitted() { if (!disableOnCommitted) { onResponseCommitted(); } else if (logger.isDebugEnabled()) { logger.debug("Skip invoking on"); } } /** * Ensures {@link OnCommittedResponseWrapper#onResponseCommitted()} is invoked before calling the prior to methods that commit the response. We delegate all methods * to the original {@link java.io.PrintWriter} to ensure that the behavior is as close to the original {@link java.io.PrintWriter} * as possible. See SEC-2039 * @author Rob Winch */ private class SaveContextPrintWriter extends PrintWriter { private final PrintWriter delegate; public SaveContextPrintWriter(PrintWriter delegate) { super(delegate); this.delegate = delegate; } public void flush() { doOnResponseCommitted(); delegate.flush(); } public void close() { doOnResponseCommitted(); delegate.close(); } public int hashCode() { return delegate.hashCode(); } public boolean equals(Object obj) { return delegate.equals(obj); } public String toString() { return getClass().getName() + "[delegate=" + delegate.toString() + "]"; } public boolean checkError() { return delegate.checkError(); } public void write(int c) { delegate.write(c); } public void write(char[] buf, int off, int len) { delegate.write(buf, off, len); } public void write(char[] buf) { delegate.write(buf); } public void write(String s, int off, int len) { delegate.write(s, off, len); } public void write(String s) { delegate.write(s); } public void print(boolean b) { delegate.print(b); } public void print(char c) { delegate.print(c); } public void print(int i) { delegate.print(i); } public void print(long l) { delegate.print(l); } public void print(float f) { delegate.print(f); } public void print(double d) { delegate.print(d); } public void print(char[] s) { delegate.print(s); } public void print(String s) { delegate.print(s); } public void print(Object obj) { delegate.print(obj); } public void println() { delegate.println(); } public void println(boolean x) { delegate.println(x); } public void println(char x) { delegate.println(x); } public void println(int x) { delegate.println(x); } public void println(long x) { delegate.println(x); } public void println(float x) { delegate.println(x); } public void println(double x) { delegate.println(x); } public void println(char[] x) { delegate.println(x); } public void println(String x) { delegate.println(x); } public void println(Object x) { delegate.println(x); } public PrintWriter printf(String format, Object... args) { return delegate.printf(format, args); } public PrintWriter printf(Locale l, String format, Object... args) { return delegate.printf(l, format, args); } public PrintWriter format(String format, Object... args) { return delegate.format(format, args); } public PrintWriter format(Locale l, String format, Object... args) { return delegate.format(l, format, args); } public PrintWriter append(CharSequence csq) { return delegate.append(csq); } public PrintWriter append(CharSequence csq, int start, int end) { return delegate.append(csq, start, end); } public PrintWriter append(char c) { return delegate.append(c); } } /** * Ensures{@link OnCommittedResponseWrapper#onResponseCommitted()} is invoked before calling methods that commit the response. We delegate all methods * to the original {@link javax.servlet.ServletOutputStream} to ensure that the behavior is as close to the original {@link javax.servlet.ServletOutputStream} * as possible. See SEC-2039 * * @author Rob Winch */ private class SaveContextServletOutputStream extends ServletOutputStream { private final ServletOutputStream delegate; public SaveContextServletOutputStream(ServletOutputStream delegate) { this.delegate = delegate; } public void write(int b) throws IOException { this.delegate.write(b); } public void flush() throws IOException { doOnResponseCommitted(); delegate.flush(); } public void close() throws IOException { doOnResponseCommitted(); delegate.close(); } public int hashCode() { return delegate.hashCode(); } public boolean equals(Object obj) { return delegate.equals(obj); } public void print(boolean b) throws IOException { delegate.print(b); } public void print(char c) throws IOException { delegate.print(c); } public void print(double d) throws IOException { delegate.print(d); } public void print(float f) throws IOException { delegate.print(f); } public void print(int i) throws IOException { delegate.print(i); } public void print(long l) throws IOException { delegate.print(l); } public void print(String arg0) throws IOException { delegate.print(arg0); } public void println() throws IOException { delegate.println(); } public void println(boolean b) throws IOException { delegate.println(b); } public void println(char c) throws IOException { delegate.println(c); } public void println(double d) throws IOException { delegate.println(d); } public void println(float f) throws IOException { delegate.println(f); } public void println(int i) throws IOException { delegate.println(i); } public void println(long l) throws IOException { delegate.println(l); } public void println(String s) throws IOException { delegate.println(s); } public void write(byte[] b) throws IOException { delegate.write(b); } public void write(byte[] b, int off, int len) throws IOException { delegate.write(b, off, len); } public String toString() { return getClass().getName() + "[delegate=" + delegate.toString() + "]"; } } }