// 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 streamer;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import streamer.debug.FakeSink;
import streamer.debug.FakeSource;
public class BaseElement implements Element {
protected String id;
/**
* Constant for @see cap() method to indicate that length is not restricted.
*/
public static final int UNLIMITED = -1;
/**
* Set to true to enable debugging messages.
*/
protected boolean verbose = false;
/**
* Limit on number of packets sent to sink from this element. Can be handy for
* fake elements and handshake-related elements.
*/
protected int numBuffers = 0;
/**
* Number of packets sent to sink.
*/
protected int packetNumber = 0;
/**
* Recommended size for incoming buffer in pull mode.
*/
protected int incommingBufLength = -1;
protected Map<String, DataSource> inputPads = new HashMap<String, DataSource>();
protected Map<String, DataSink> outputPads = new HashMap<String, DataSink>();
public BaseElement(String id) {
this.id = id;
verbose = System.getProperty("streamer.Element.debug", "false").equals("true") || System.getProperty("streamer.Element.debug", "").contains(id);
}
@Override
public String toString() {
return "Element(" + id + ")";
}
@Override
public Link getLink(String padName) {
if (inputPads.containsKey(padName))
return (Link)inputPads.get(padName);
else if (outputPads.containsKey(padName))
return (Link)outputPads.get(padName);
else
return null;
}
@Override
public Set<String> getPads(Direction direction) {
switch (direction) {
case IN:
return inputPads.keySet();
case OUT:
return outputPads.keySet();
}
return null;
}
@Override
public void validate() {
for (String padName : inputPads.keySet()) {
if (inputPads.get(padName) == null)
throw new RuntimeException("[ " + this + "] Required input pad is not connected. Pad name: " + padName + ".");
}
for (String padName : outputPads.keySet()) {
if (outputPads.get(padName) == null)
throw new RuntimeException("[ " + this + "] Required output pad is not connected. Pad name: " + padName + ".");
}
}
@Override
public void setLink(String padName, Link link, Direction direction) {
switch (direction) {
case IN:
if (inputPads.get(padName) != null)
throw new RuntimeException("Cannot link more than one wire to same pad. Element: " + this + ", pad: " + padName + ":" + direction + ", new link: "
+ link + ", existing link: " + inputPads.get(padName) + ".");
inputPads.put(padName, link);
link.setSink(this);
break;
case OUT:
if (outputPads.get(padName) != null)
throw new RuntimeException("Cannot link more than one wire to same pad. Element: " + this + ", pad: " + padName + ":" + direction + ", new link: "
+ link + ", existing link: " + outputPads.get(padName) + ".");
outputPads.put(padName, link);
link.setSource(this);
break;
}
}
@Override
public void dropLink(String padName) {
if (inputPads.containsKey(padName)) {
Link link = (Link)inputPads.remove(padName);
if (link != null)
link.setSink(null);
}
if (outputPads.containsKey(padName)) {
Link link = (Link)outputPads.remove(padName);
if (link != null)
link.setSource(null);
}
}
/**
* By default, try to pull data from input links.
*
* Override this method in data source elements.
*/
@Override
public void poll(boolean block) {
// inputPads can be changed in handleData (see switchOff in OneTimeSwitch)
// as this results in an undefined response from the iterator on inputPads
// use a copy of the map to iterate over.
Map<String, DataSource> pads = new HashMap<String, DataSource>();
pads.putAll(inputPads);
for (DataSource source : pads.values()) {
Link link = (Link)source;
ByteBuffer buf = link.pull(block);
if (buf != null) {
handleData(buf, link);
}
}
}
/**
* By default, do nothing with incoming data and retransmit data to all output
* pads.
*/
@Override
public void handleData(ByteBuffer buf, Link link) {
if (verbose)
System.out.println("[" + this + "] INFO: Data received: " + buf + ".");
pushDataToAllOuts(buf);
}
/**
* Send data to all output pads.
*/
protected final void pushDataToAllOuts(ByteBuffer buf) {
if (buf == null)
throw new NullPointerException();
//return;
if (outputPads.size() == 0)
throw new RuntimeException("Number of outgoing connection is zero. Cannot send data to output. Data: " + buf + ".");
// Send data to all pads with OUT direction
for (DataSink out : outputPads.values()) {
if (verbose)
System.out.println("[" + this + "] INFO: Sending buf " + buf + " to " + out + ".");
buf.rewindCursor();
buf.ref();
out.sendData(buf);
}
buf.unref();
packetNumber++;
}
/**
* Send data to given pad only.
*/
protected void pushDataToPad(String padName, ByteBuffer buf) {
if (buf == null)
return;
if (verbose)
System.out.println("[" + this + "] INFO: Sending buf " + buf + " to " + padName + ".");
DataSink link = outputPads.get(padName);
if (link == null)
throw new RuntimeException("Output pad of " + this + " element is not connected to a link. Pad name: " + padName + ".");
buf.rewindCursor();
link.sendData(buf);
}
/**
* By default, do nothing with incoming event and retransmit event to all
* pads.
*/
@SuppressWarnings("incomplete-switch")
@Override
public void handleEvent(Event event, Direction direction) {
if (verbose)
System.out.println("[" + this + "] INFO: Event " + event + ":" + direction + " is received.");
switch (event) {
case STREAM_CLOSE:
onClose();
break;
case STREAM_START:
onStart();
break;
}
sendEventToAllPads(event, direction);
}
/**
* Override this method to do something when STREAM_CLOSE event arrives.
*/
protected void onClose() {
}
/**
* Override this method to do something when STREAM_START event arrives.
*/
protected void onStart() {
}
/**
* Send event to all outputs.
*
* @param event
* a event
* @param direction
* IN to send event to input pads, OUT to send event to all output
* pads
*/
protected final void sendEventToAllPads(Event event, Direction direction) {
if (verbose)
System.out.println("[" + this + "] INFO: Sending event " + event + ":" + direction + ".");
switch (direction) {
case IN:
// Send event to all pads with IN direction
for (DataSource in : inputPads.values()) {
in.sendEvent(event, direction);
}
break;
case OUT:
// Send event to all pads with OUT direction
for (DataSink out : outputPads.values()) {
out.sendEvent(event, direction);
}
break;
}
}
/**
* Ensure that packet has required minimum and maximum length, cuts tail when
* necessary.
*
* @param buf
* a buffer
* @param minLength
* minimum length of packet or -1
* @param maxLength
* maximum length of packet or -1
* @param link
* source link, to push unnecessary data back
* @param fromCursor
* if true, then position will be included into calculation
* @return true, if buffer is long enough, false otherwise
*/
public boolean cap(ByteBuffer buf, int minLength, int maxLength, Link link, boolean fromCursor) {
if (buf == null)
return false;
int length = buf.length;
int cursor;
if (fromCursor)
cursor = buf.cursor;
else
cursor = 0;
length -= cursor;
if ((minLength < 0 || length >= minLength) && (maxLength < 0 || length <= maxLength))
// Buffer is already in bounds
return true;
// Buffer is too small, wait for the rest of buffer
if (minLength >= 0 && length < minLength) {
if (verbose)
System.out.println("[" + this + "] INFO: Buffer is too small. Min length: " + minLength + ", data length (after cursor): " + length + ".");
link.pushBack(buf.slice(0, length + cursor, true), minLength + cursor);
return false;
} else if (maxLength >= 0 && length > maxLength) {
if (verbose)
System.out.println("[" + this + "] INFO: Buffer is too big. Max length: " + maxLength + ", data length (after cursor): " + length + ".");
// Buffer is too big, cut unnecessary tail
link.pushBack(buf.slice(maxLength + cursor, length - maxLength, true));
buf.length = maxLength + cursor;
}
return true;
}
@Override
public void dropLink(Link link) {
if (inputPads.containsValue(link)) {
for (Entry<String, DataSource> entry : inputPads.entrySet())
if (link.equals(entry.getValue())) {
inputPads.remove(entry.getKey());
break;
}
}
if (outputPads.containsValue(link)) {
for (Entry<String, DataSink> entry : outputPads.entrySet())
if (link.equals(entry.getValue())) {
outputPads.remove(entry.getKey());
break;
}
}
}
@Override
public void replaceLink(Link existingLink, Link newLink) {
if (inputPads.containsValue(existingLink)) {
for (Entry<String, DataSource> entry : inputPads.entrySet())
if (existingLink.equals(entry.getValue())) {
inputPads.put(entry.getKey(), newLink);
newLink.setSink(this);
break;
}
}
if (outputPads.containsValue(existingLink)) {
for (Entry<String, DataSink> entry : outputPads.entrySet())
if (existingLink.equals(entry.getValue())) {
outputPads.put(entry.getKey(), newLink);
newLink.setSource(this);
break;
}
}
}
@Override
public String getId() {
return id;
}
/**
* Example.
*/
public static void main(String args[]) {
Element source = new FakeSource("source") {
{
verbose = true;
numBuffers = 10;
incommingBufLength = 3;
delay = 100;
}
};
Element sink = new FakeSink("sink") {
{
verbose = true;
}
};
Pipeline pipeline = new PipelineImpl("test");
pipeline.add(source);
pipeline.add(new BaseElement("t1"));
pipeline.add(new BaseElement("t2"));
pipeline.add(new BaseElement("t3"));
pipeline.add(new BaseElement("t4"));
pipeline.add(sink);
pipeline.link("source", "t1", "t2", "t3", "t4", "sink");
// Links between source-t1-t2 will operate in pull mode.
// Links between t3-t4-sink will operate in push mode.
// Link between t2-t3 will run main loop (pull from source and push to
// sink).
Link link = pipeline.getLink("t3", STDOUT);
link.sendEvent(Event.STREAM_START, Direction.IN);
link.run();
}
}