List<LocatedBlock> blocks = dfs.getNamenode().getBlockLocations(filename, 0,
Long.MAX_VALUE).getLocatedBlocks();
for (int i = 0; i < blocks.size(); i++) {
if (blocks.get(i).getBlock().getBlockId() == blockId) {
if (i != blocks.size() - 1) {
LocatedBlock nextBlock = blocks.get(i + 1);
nextBlockIdStr = Long.toString(nextBlock.getBlock().getBlockId());
nextGenStamp = Long.toString(nextBlock.getBlock()
.getGenerationStamp());
nextStartOffset = 0;
nextBlockSize = nextBlock.getBlock().getNumBytes();
DatanodeInfo d = JspHelper.bestNode(nextBlock, conf);
nextDatanodePort = d.getXferPort();
nextHost = d.getIpAddr();
nextPort = d.getInfoPort();
}
}
}
} else {
// we are in the same block
nextBlockIdStr = blockId.toString();
nextStartOffset = startOffset + chunkSizeToView;
nextBlockSize = blockSize;
nextGenStamp = genStamp.toString();
}
String nextUrl = null;
if (nextBlockIdStr != null) {
nextUrl = HttpConfig.getSchemePrefix() + canonicalize(nextHost) + ":" + nextPort
+ "/browseBlock.jsp?blockId=" + nextBlockIdStr
+ "&blockSize=" + nextBlockSize
+ "&startOffset=" + nextStartOffset
+ "&genstamp=" + nextGenStamp
+ "&filename=" + URLEncoder.encode(filename, "UTF-8")
+ "&chunkSizeToView=" + chunkSizeToView
+ "&datanodePort=" + nextDatanodePort
+ "&namenodeInfoPort=" + namenodeInfoPort
+ JspHelper.getDelegationTokenUrlParam(tokenString)
+ JspHelper.getUrlParam(JspHelper.NAMENODE_ADDRESS, nnAddr);
out.print("<a href=\"" + nextUrl + "\">View Next chunk</a> ");
}
// determine data for the prev link
String prevBlockIdStr = null;
String prevGenStamp = null;
long prevStartOffset = 0;
long prevBlockSize = 0;
String prevHost = req.getServerName();
int prevPort = req.getServerPort();
int prevDatanodePort = datanodePort;
if (startOffset == 0) {
List<LocatedBlock> blocks = dfs.getNamenode().getBlockLocations(filename, 0,
Long.MAX_VALUE).getLocatedBlocks();
for (int i = 0; i < blocks.size(); i++) {
if (blocks.get(i).getBlock().getBlockId() == blockId) {
if (i != 0) {
LocatedBlock prevBlock = blocks.get(i - 1);
prevBlockIdStr = Long.toString(prevBlock.getBlock().getBlockId());
prevGenStamp = Long.toString(prevBlock.getBlock()
.getGenerationStamp());
prevStartOffset = prevBlock.getBlock().getNumBytes()
- chunkSizeToView;
if (prevStartOffset < 0)
prevStartOffset = 0;
prevBlockSize = prevBlock.getBlock().getNumBytes();
DatanodeInfo d = JspHelper.bestNode(prevBlock, conf);
prevDatanodePort = d.getXferPort();
prevHost = d.getIpAddr();
prevPort = d.getInfoPort();
}