...
The created task will read a text file at a specified location and places orders for stocks that are given in the text file is created. The text file has entries such as this one:
| Code Block |
|---|
IBM,100,120.50
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Each line in the text file contains details for a stock order:
...
The complete code listing of the Task class is provided below:
| Code Block |
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public class PlaceStockOrderTask implements Task, ManagedLifecycle {
private Log log = LogFactory.getLog(PlaceStockOrderTask.class);
private String to;
private String stockFile;
private SynapseEnvironment synapseEnvironment;
public void execute() {
log.debug("PlaceStockOrderTask begin");
if (synapseEnvironment == null) {
log.error("Synapse Environment not set");
return; }
if (to == null) {
log.error("to not set");
return; }
File existFile = new File(stockFile);
if(!existFile.exists()) {
log.debug("waiting for stock file");
return; }
try {
// file format IBM,100,120.50
BufferedReader reader = new BufferedReader(new FileReader(stockFile));
String line = null;
while( (line = reader.readLine()) != null){
line = line.trim();
if(line == "") {
continue;
}
String[] split = line.split(",");
String symbol = split[0];
String quantity = split[1];
String price = split[2];
MessageContext mc = synapseEnvironment.createMessageContext();
mc.setTo(new EndpointReference(to));
mc.setSoapAction("urn:placeOrder");
mc.setProperty("OUT_ONLY", "true");
OMElement placeOrderRequest = createPlaceOrderRequest(symbol, quantity, price);
PayloadHelper.setXMLPayload(mc, placeOrderRequest);
synapseEnvironment.injectMessage(mc);
log.info("placed order symbol:" + symbol + " quantity:" + quantity + " price:" + price);
}
reader.close();
}
catch (IOException e) {
throw new SynapseException("error reading file", e);
}
File renamefile = new File(stockFile);
renamefile.renameTo(new File(stockFile + "." + System.currentTimeMillis()));
log.debug("PlaceStockOrderTask end"); }
public static OMElement createPlaceOrderRequest(String symbol, String qty, String purchPrice) {
OMFactory factory = OMAbstractFactory.getOMFactory();
OMNamespace ns = factory.createOMNamespace("http://services.samples/xsd", "m0");
OMElement placeOrder= factory.createOMElement("placeOrder", ns);
OMElement order = factory.createOMElement("order", ns);
OMElement price = factory.createOMElement("price", ns);
OMElement quantity = factory.createOMElement("quantity", ns);
OMElement symb = factory.createOMElement("symbol", ns);
price.setText(purchPrice);
quantity.setText(qty);
symb.setText(symbol);
order.addChild(price);
order.addChild(quantity);
order.addChild(symb);
placeOrder.addChild(order);
return placeOrder;
}
public void destroy() {
}
public void init(SynapseEnvironment synapseEnvironment) {
this.synapseEnvironment = synapseEnvironment;
}
public SynapseEnvironment getSynapseEnvironment() {
return synapseEnvironment;
}
public void setSynapseEnvironment(SynapseEnvironment synapseEnvironment) {
this.synapseEnvironment = synapseEnvironment;
}
public String getTo() {
return to;
}
public void setTo(String to) {
this.to = to;
}
public String getStockFile() {
return stockFile;
}
public void setStockFile(String stockFile) {
this.stockFile = stockFile;
}
}
|
...
Since a task implements ManagedLifecyle interface, ESB will call the init() method at the initialization of a Task object and destroy() method when a Task object is destroyed:
| Code Block |
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public interface ManagedLifecycle {
public void init(SynapseEnvironment se);
public void destroy();
}
|
...
For example, the following properties in the Task class
| Code Block |
|---|
public String getStockFile() {
return stockFile;
}
public void setStockFile(String stockFile) {
this.stockFile = stockFile;
}
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are initialized with the given values within the property element of the task in the configuration.
| Code Block |
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<syn:property xmlns="http://ws.apache.org/ns/synapse" name="stockFile"value="/home/upul/test/stock.txt"/>
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For those properties given as XML elements, properties need to be defined within the Task class using the following format:
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|---|
public void setMessage(OMElement elem) {
message = elem;}
|
...
(OMElement comes from Apache AXIOM which is used by WSO2 ESB. AXIOM is an object model similar to DOM. To learn more about AXIOM, see the tutorial in the AXIOM tutorialuser guide.)
| Code Block |
|---|
<property name="message">
<m0:getQuote xmlns:m0="http://services.samples/xsd">
<m0:request>
<m0:symbol>IBM</m0:symbol>
</m0:request>
</m0:getQuote>
</property>
|
...
1. Log in to the ESB console.
2. Click the "Main" button to access the "Manage" menu.
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10. Copy the stockfile.txt to a new directory. The stockfile.txt will contain the following entries:
| Code Block |
|---|
IBM,100,120.50
MSFT,200,70.25
SUN,400,60.758.
|
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12. Enter 15000 to "Interval."
13. Click "Schedule."
| Excerpt | ||
|---|---|---|
| ||
Instructions on how to create a custom task for WSO2 ESB. |