From 4a51a8f96715ffb2a42189b93b9fa91b453b8530 Mon Sep 17 00:00:00 2001
From: sg481n <sg481n@att.com>
Date: Thu, 3 Aug 2017 17:39:12 -0400
Subject:  [AAF-21] Initial code import
MIME-Version: 1.0
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Change-Id: Ia1dd196befd061f6ba0c2be6bf4456a30ea50f97
Signed-off-by: sg481n <sg481n@att.com>
---
 .../com/att/cadi/BufferedServletInputStream.java   | 215 +++++++++++++++++++++
 1 file changed, 215 insertions(+)
 create mode 100644 core/src/main/java/com/att/cadi/BufferedServletInputStream.java

(limited to 'core/src/main/java/com/att/cadi/BufferedServletInputStream.java')

diff --git a/core/src/main/java/com/att/cadi/BufferedServletInputStream.java b/core/src/main/java/com/att/cadi/BufferedServletInputStream.java
new file mode 100644
index 0000000..88114b2
--- /dev/null
+++ b/core/src/main/java/com/att/cadi/BufferedServletInputStream.java
@@ -0,0 +1,215 @@
+/*******************************************************************************
+ * ============LICENSE_START====================================================
+ * * org.onap.aai
+ * * ===========================================================================
+ * * Copyright © 2017 AT&T Intellectual Property. All rights reserved.
+ * * Copyright © 2017 Amdocs
+ * * ===========================================================================
+ * * 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.
+ * * ============LICENSE_END====================================================
+ * *
+ * * ECOMP is a trademark and service mark of AT&T Intellectual Property.
+ * *
+ ******************************************************************************/
+package com.att.cadi;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import javax.servlet.ServletInputStream;
+
+/**
+ * BufferedServletInputStream
+ * 
+ * There are cases in brain-dead middleware (SOAP) where they store routing information in the content.
+ * 
+ * In HTTP, this requires reading the content from the InputStream which, of course, cannot be re-read.
+ * 
+ * BufferedInputStream exists to implement the "Mark" protocols for Streaming, which will enable being 
+ * re-read.  Unfortunately, J2EE chose to require a "ServletInputStream" as an abstract class, rather than
+ * an interface, which requires we create a delegating pattern, rather than the preferred inheriting pattern. 
+ * 
+ * Unfortunately, the standard "BufferedInputStream" cannot be used, because it simply creates a byte array
+ * in the "mark(int)" method of that size.  This is not appropriate for this application, because the Header 
+ * can be potentially huge, and if a buffer was allocated to accommodate all possibilities, the cost of memory 
+ * allocation would be too large for high performance transactions.
+ *
+ * 
+ *
+ */
+public class BufferedServletInputStream extends ServletInputStream {
+	private static final int NONE = 0;
+	private static final int STORE = 1;
+	private static final int READ = 2;
+	
+	private InputStream is;
+	private int state = NONE;
+	private Capacitor capacitor;
+
+	public BufferedServletInputStream(InputStream is) {
+		this.is = is;
+		capacitor = null;
+	}
+
+
+	// @Override
+	public int read() throws IOException {
+		int value=-1;
+		if(capacitor==null) {
+			value=is.read();
+		} else {
+			switch(state) {
+				case STORE:
+					value = is.read();
+					if(value>=0) {
+						capacitor.put((byte)value);
+					}
+					break;
+				case READ:
+					value = capacitor.read();
+					if(value<0) {
+						capacitor.done();
+						capacitor=null; // all done with buffer
+						value = is.read();
+					}
+			}
+		} 
+		return value;
+	}
+
+	// @Override
+	public int read(byte[] b) throws IOException {
+		return read(b,0,b.length);
+	}
+
+
+	// @Override
+	public int read(byte[] b, int off, int len) throws IOException {
+		int count = -1;
+		if(capacitor==null) {
+			count = is.read(b,off,len);
+		} else {
+			switch(state) {
+				case STORE:
+					count = is.read(b, off, len);
+					if(count>0) {
+						capacitor.put(b, off, count);
+					}
+					break;
+				case READ:
+					count = capacitor.read(b, off, len);
+//					System.out.println("Capacitor read " + count);
+					if(count<=0) {
+						capacitor.done();
+						capacitor=null; // all done with buffer
+					}
+					if(count<len) {
+						int temp = is.read(b, count, len-count);
+//						System.out.println("Capacitor done, stream read " + temp);
+						if(temp>0) { // watch for -1
+							count+=temp;
+						} else {
+							if(count<=0)count = temp; // must account for Stream coming back -1  
+						}
+					}
+					break;
+			}
+		}
+//		System.out.println("read reports " + count);
+		return count;
+	}
+
+	// @Override
+	public long skip(long n) throws IOException {
+		long skipped = capacitor.skip(n);
+		if(skipped<n) {
+			skipped += is.skip(n-skipped);
+		}
+		return skipped;
+	}
+
+
+	// @Override
+	public int available() throws IOException {
+		int count = is.available();
+		if(capacitor!=null)count+=capacitor.available();
+		return count;		
+	}
+	
+	/**
+	 * Return just amount buffered (for debugging purposes, mostly)
+	 * @return
+	 */
+	public int buffered() {
+		return capacitor.available();
+	}
+
+
+	// @Override
+	public void close() throws IOException {
+		if(capacitor!=null) {
+			capacitor.done();
+			capacitor=null;
+		}
+		is.close();
+	}
+
+
+	/**
+	 * Note: Readlimit is ignored in this implementation, because the need was for unknown buffer size which wouldn't 
+	 * require allocating and dumping huge chunks of memory every use, or risk overflow.
+	 */
+	// @Override
+	public synchronized void mark(int readlimit) {
+		switch(state) {
+			case NONE:
+				capacitor = new Capacitor();
+				break;
+			case READ:
+				capacitor.done();
+				break;
+			// ignore case STORE:
+		}
+		state = STORE;
+	}
+
+
+	/**
+	 * Reset Stream
+	 * 
+	 * Calling this twice is not supported in typical Stream situations, but it is allowed in this service.  The caveat is that it can only reset
+	 * the data read in since Mark has been called.  The data integrity is only valid if you have not continued to read past what is stored.
+	 *  
+	 */
+	// @Override
+	public synchronized void reset() throws IOException {
+		switch(state) {
+			case STORE:
+				capacitor.setForRead();
+				state = READ;
+				break;
+			case READ:
+				capacitor.reset();
+				break;
+//				throw new IOException("InputStream is already in READ state");
+			case NONE: 
+				throw new IOException("InputStream has not been marked");
+		}
+	}
+
+
+	// @Override
+	public boolean markSupported() {
+		return true;
+	}
+}
-- 
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