Sample HTTP client participant

HttpQuery.java

package org.jpos.rest.client;

import java.io.IOException;
import java.io.Serializable;
import java.io.ByteArrayInputStream;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.HttpMethod;
import org.apache.commons.httpclient.DefaultHttpMethodRetryHandler;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PutMethod;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.methods.DeleteMethod;
import org.apache.commons.httpclient.params.HttpMethodParams;

import org.jdom2.Element;
import org.jdom2.Document;
import org.jdom2.JDOMException;
import org.jdom2.input.SAXBuilder;

import org.jpos.util.Log;
import org.jpos.core.Configurable;
import org.jpos.core.Configuration;
import org.jpos.transaction.Context;
import org.jpos.transaction.TransactionParticipant;

@SuppressWarnings("unused")
public class HttpQuery extends Log implements TransactionParticipant, Configurable {
    Configuration cfg;
    public static final String REST_URL      = "REST_URL";
    public static final String REST_PARAMS   = "REST_PARAMS";
    public static final String REST_METHOD   = "REST_METHOD";
    public static final String REST_REQUEST  = "REST_REQUEST";
    public static final String REST_RESPONSE = "REST_RESPONSE";

    public HttpQuery () {
        super();
    }
    public int prepare (long id, Serializable o) {
        Context ctx = (Context) o;
        HttpClient client = new HttpClient();
        client.setConnectionTimeout (cfg.getInt ("timeout", 60000));
        HttpMethod method;
        String methodName = ctx.getString (REST_METHOD, cfg.get ("method", "GET"));
        String url = getURL (ctx);
        byte[] payLoad = (byte[]) ctx.get (REST_REQUEST);

        // payLoad = "<isomsg><field id='0' value='0800' /></isomsg>".getBytes();

        if ("PUT".equalsIgnoreCase (methodName)) {
            method = new PutMethod(url);
            if (payLoad != null)
              ((PutMethod)method).setRequestBody(new ByteArrayInputStream(payLoad));
        } else if ("POST".equalsIgnoreCase (methodName)) {
            method = new PostMethod(url);
            if (payLoad != null)
              ((PostMethod)method).setRequestBody(new ByteArrayInputStream(payLoad));
        } else if ("DELETE".equalsIgnoreCase (methodName)) {
            method = new DeleteMethod(url);
        } else {
            method = new GetMethod(url);
        }
        method.getParams().setParameter(
            HttpMethodParams.RETRY_HANDLER, 
            new DefaultHttpMethodRetryHandler(cfg.getInt ("retry", 3), false));
        try {
            int statusCode = client.executeMethod(method);
            if (statusCode != HttpStatus.SC_OK) {
                ctx.log ("HttpQuery error -- status code=" + statusCode);
                return ABORTED;
            }
            byte[] responseBody = method.getResponseBody();
            ctx.put (cfg.get ("response", REST_RESPONSE), parseMsg (responseBody));
            return PREPARED;
        } catch (Exception e) {
            ctx.log (e);
        } finally {
            method.releaseConnection();
        }
        return ABORTED;
    }
    public int prepareForAbort (long id, Serializable o) {
        if (cfg.getBoolean ("on-abort", false))
            return prepare (id, o);
        return PREPARED;
    }
    public void commit (long id, Serializable o) { }
    public void abort (long id, Serializable o) { }
    public void setConfiguration (Configuration cfg) {
        this.cfg = cfg;
    }
    private String getURL (Context ctx) {
        StringBuilder sb = new StringBuilder (
            ctx.getString (REST_URL, cfg.get ("url", ""))
        );
        String params = ctx.getString (REST_PARAMS, "");
        if (params.length() > 0) {
            sb.append ('?');
            sb.append (params);
        }
        return sb.toString();
    }
    private Element parseMsg (byte[] b) throws JDOMException, IOException {
        if (b == null)
            return null;
        SAXBuilder builder = new SAXBuilder ();
        builder.setValidation (false);
        Document doc = builder.build (
            new ByteArrayInputStream (b)
        );
        return doc.getRootElement ();
    }
}