Here is some simple code that demonstrates using typica for SQS and EC2.

Introduction

This code can be found in Subverion, but it is sometimes helpful to document code sample in something approximating a users manual.

SQS

Usage of SQS is simple. First, you create or get an existing queue. For that, you have the QueueService object. When using a specific queue, the MessageQueue object provides methods for queue interaction.

Enqueue Sample

http://typica.googlecode.com/svn/trunk/test/java/EnqueueSample.java

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.xerox.amazonws.sqs2.MessageQueue;
import com.xerox.amazonws.sqs2.Message;
import com.xerox.amazonws.sqs2.SQSUtils;

/**
 * This sample application creates a queue with the specified name (if the queue doesn't
 * already exist), and then sends (enqueues) a message to the queue.
 */
public class EnqueueSample {
	private static Log log = LogFactory.getLog(EnqueueSample.class);

	public static void main( String[] args ) {
		final String AWSAccessKeyId = "[AWS Access Id]";
		final String SecretAccessKey = "[AWS Secret Key]";

		try {
			if (args.length < 2) {
				log.error("usage: EnqueueSample <queueId> <message>");
			}
			String queueName = args[0];
			String message = args[1];

			// Create the message queue object
			MessageQueue msgQueue = SQSUtils.connectToQueue(queueName, AWSAccessKeyId, SecretAccessKey);
			log.info(" url returned = "+msgQueue.getUrl());

			String msgId = msgQueue.sendMessage(message);
			log.info( "Sent message with id " + msgId );
		} catch ( Exception ex ) {
			log.error( "EXCEPTION", ex );
		}
	}
}

Dequeue Sample

http://typica.googlecode.com/svn/trunk/test/java/DequeueSample.java

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.xerox.amazonws.sqs2.MessageQueue;
import com.xerox.amazonws.sqs2.Message;
import com.xerox.amazonws.sqs2.SQSUtils;

/**
 * This sample application retrieves (dequeues) a message from the queue specified by
 * the value of the queuename parameter. If successful, it deletes the message from the queue.
 * On error, it retries a number of times.
 */
public class DequeueSample {
	private static Log log = LogFactory.getLog(DequeueSample.class);

	public static void main( String[] args ) {
		final String AWSAccessKeyId = "[AWS Access Id]";
		final String SecretAccessKey = "[AWS Secret Key]";

		int count = 0;
		try {
			if (args.length < 1) {
				log.error("usage: DequeueSample <queueId>");
			}
			String queueName = args[0];

			// Retrieve the message queue object (by name).
			MessageQueue msgQueue = SQSUtils.connectToQueue(queueName, AWSAccessKeyId, SecretAccessKey);

			// Try to retrieve (dequeue) the message, and then delete it.
			Message msg = null;
			while (true) {
				msg = msgQueue.receiveMessage();
				if (msg == null) {
					logger.debug("nothing... retrying");
					try { Thread.sleep(1000); } catch (Exception ex) {}
					continue;
				}
				String text = msg.getMessageBody();
				logger.info("msg : "+text);
				msgQueue.deleteMessage(msg);
				logger.info( "Deleted message id " + msg.getMessageId());
				count++;
			}
		} catch ( Exception ex ) {
			log.error( "EXCEPTION", ex );
		}
		log.debug("Deleted "+count+" messages");
	}
}

EC2

The Jec2 class provides methods to perform all of the functions you can perform using the EC2 QUERY API.

http://typica.googlecode.com/svn/trunk/test/java/Ec2Sample.java

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.xerox.amazonws.ec2.ConsoleOutput;
import com.xerox.amazonws.ec2.GroupDescription;
import com.xerox.amazonws.ec2.Jec2;
import com.xerox.amazonws.ec2.ImageDescription;
import com.xerox.amazonws.ec2.ImageListAttributeItem;
import com.xerox.amazonws.ec2.ImageListAttribute.ImageListAttributeItemType;
import com.xerox.amazonws.ec2.KeyPairInfo;
import com.xerox.amazonws.ec2.ReservationDescription;
import com.xerox.amazonws.ec2.ReservationDescription.Instance;

public class Ec2Sample {
        private static Log log = LogFactory.getLog(EC2Sample.class);

	public static void main(String [] args) throws Exception {
		final String AWSAccessKeyId = "[AWS Access Id]";
		final String SecretAccessKey = "[AWS Secret Key]";

		Jec2 ec2 = new Jec2(AWSAccessKeyId, SecretAccessKey);
	
		// describe images
		List<String> params = new ArrayList<String>();
		List<ImageDescription> images = ec2.describeImages(params);
		log.info("Available Images");
		for (ImageDescription img : images) {
			if (img.getImageState().equals("available")) {
				log.info(img.getImageId()+"\t"+img.getImageLocation()+"\t"+img.getImageOwnerId());
			}
		}

		// describe instances
		params = new ArrayList<String>();
		List<ReservationDescription> instances = ec2.describeInstances(params);
		log.info("Instances");
		String instanceId = "";
		for (ReservationDescription res : instances) {
			log.info(res.getOwner()+"\t"+res.getReservationId());
			if (res.getInstances() != null) {
				for (Instance inst : res.getInstances()) {
					log.info("\t"+inst.getImageId()+"\t"+inst.getDnsName()+"\t"+inst.getState()+"\t"+inst.getKeyName());
					instanceId = inst.getInstanceId();
				}
			}
		}

		// test console output
		ConsoleOutput consOutput = ec2.getConsoleOutput(instanceId);
		log.info("Console Output:");
		log.info(consOutput.getOutput());

		// show keypairs
		List<KeyPairInfo> info = ec2.describeKeyPairs(new String [] {});
		log.info("keypair list");
		for (KeyPairInfo i : info) {
			log.info("keypair : "+i.getKeyName()+", "+i.getKeyFingerprint());
		}
	}
}

SimpleDB

This is the source code (as of August '09) for the sdbShell. The purpose of posting it here is that it access all of the functionality of SimpleDB and can provide a reference to those trying to do various things in SimpleDB with typica.

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;

import com.xerox.amazonws.sdb.Domain;
import com.xerox.amazonws.sdb.DomainMetadataResult;
import com.xerox.amazonws.sdb.Item;
import com.xerox.amazonws.sdb.ItemAttribute;
import com.xerox.amazonws.sdb.ItemListener;
import com.xerox.amazonws.sdb.ListDomainsResult;
import com.xerox.amazonws.sdb.QueryResult;
import com.xerox.amazonws.sdb.QueryWithAttributesResult;
import com.xerox.amazonws.sdb.SDBException;
import com.xerox.amazonws.sdb.SimpleDB;

/**
 * Sample application demonstrating various operations against SDS.  
 *
 */
public class sdbShell {
	static int itemCount;

	/**
	 * Executes specified query against given domain while demonstrating pagination.
	 *
	 * @param domain	    query domain 
	 * @param queryString	query string
	 * @param maxResults	maximum number of values to return per page of results
	 */
	private static void executeQuery(Domain domain, String queryString, int maxResults) {

        String nextToken = "";
        do {
            try {
                QueryResult result = domain.listItems(queryString, nextToken, maxResults);
				List<Item> items = result.getItemList();
                for (Item i : items) {
                    System.out.println(i.getIdentifier());
                }
                nextToken = result.getNextToken();
            }
            catch (SDBException ex) {
                System.out.println("Query '" + queryString + "' Failure: ");
                ex.printStackTrace();
            }
        } while (nextToken != null && nextToken.trim().length() > 0);
        System.out.println("Done.");
	}

	/**
	 * Executes specified query against given domain.
	 *
	 * @param domain	    query domain 
	 * @param queryString	query string
	 */
	private static void executeQuery(Domain domain, String queryString) {
        executeQuery(domain, queryString, 0);
    }

	/**
	 * Main execution body.
	 *
	 * @param args	    command line arguments (none required or processed)
	 */
    public static void main(String [] args) {
		if (args.length < 2) {
			System.err.println("usage: sdbShell <access key> <secret key> [command file]");
			System.exit(1);
		}
		try {
			String awsAccessId = args[0];
			String awsSecretKey = args[1];

			if (awsAccessId == null || awsAccessId.trim().length() == 0)
			{
				System.out.println("Access key not set");
				return;
			}

			if (awsSecretKey == null || awsSecretKey.trim().length() == 0)
			{
				System.out.println("Secret key not set");
				return;
			}
			SimpleDB sds = new SimpleDB(awsAccessId, awsSecretKey, true);
			sds.setSignatureVersion(1);

			InputStream iStr = System.in;
			if (args.length > 2) {
				iStr = new FileInputStream(args[2]);
			}
			BufferedReader rdr = new BufferedReader(new InputStreamReader(iStr));
			boolean done = false;
			Domain dom = null;
			while (!done) {
				System.out.print("sdbShell> ");
				String line = rdr.readLine();
				if (line == null) { // exit, if end of input
					System.exit(0);
				}
				StringTokenizer st = new StringTokenizer(line);
				if (st.countTokens() == 0) {
					continue;
				}
				String cmd = st.nextToken().toLowerCase();
				if (cmd.equals("q") || cmd.equals("quit")) {
					done = true;
				}
				else if (cmd.equals("h") || cmd.equals("?") || cmd.equals("help")) {
					showHelp();
				}
				else if (cmd.equals("d") || cmd.equals("domains")) {
					ListDomainsResult result = sds.listDomains();
					List<Domain> domains = result.getDomainList();
					for (Domain d : domains) {
						System.out.println(d.getName());
					}
				}
				else if (cmd.equals("ad") || cmd.equals("adddomain")) {
					if (st.countTokens() != 1) {
						System.out.println("Error: need domain name.");
						continue;
					}
					Domain d = sds.createDomain(st.nextToken());
				}
				else if (cmd.equals("dd") || cmd.equals("deletedomain")) {
					if (st.countTokens() != 1) {
						System.out.println("Error: need domain name.");
						continue;
					}
					sds.deleteDomain(st.nextToken());
				}
				else if (cmd.equals("sd") || cmd.equals("setdomain")) {
					if (st.countTokens() != 1) {
						System.out.println("Error: need domain name.");
						continue;
					}
					dom = sds.getDomain(st.nextToken());
				}
				else if (cmd.equals("dm") || cmd.equals("domainmetadata")) {
					if (checkDomain(dom)) {
						DomainMetadataResult metadata = dom.getMetadata();
						System.out.println("Domain Metadata for : "+dom.getName());
						System.out.println(" ItemCount: "+metadata.getItemCount());
						System.out.println(" AttributeNameCount: "+metadata.getAttributeNameCount());
						System.out.println(" AttributeValueCount: "+metadata.getAttributeValueCount());
						System.out.println(" ItemNamesSizeBytes: "+metadata.getItemNamesSizeBytes());
						System.out.println(" AttributeNamesSizeBytes: "+metadata.getAttributeNamesSizeBytes());
						System.out.println(" AttributeValuesSizeBytes: "+metadata.getAttributeValuesSizeBytes());
						System.out.println(" Timestamp: "+metadata.getTimestamp());
					}
				}
				else if (cmd.equals("aa") || cmd.equals("addattr")) {
					if (checkDomain(dom)) {
						if (st.countTokens() < 3) {
							System.out.println("Error: need item id, attribute name and value.");
							continue;
						}
						Item item = dom.getItem(st.nextToken());
						List<ItemAttribute> list = new ArrayList<ItemAttribute>();
						String key = st.nextToken();
						String value = st.nextToken();
						if (line.indexOf('"') > -1) {
							value = line.substring(line.indexOf('"')+1, line.lastIndexOf('"'));
						}
						list.add(new ItemAttribute(key, value, false));
						item.putAttributes(list);
					}
				}
				else if (cmd.equals("ra") || cmd.equals("replaceattr")) {
					if (checkDomain(dom)) {
						if (st.countTokens() < 3) {
							System.out.println("Error: need item id, attribute name and value.");
							continue;
						}
						Item item = dom.getItem(st.nextToken());
						List<ItemAttribute> list = new ArrayList<ItemAttribute>();
						String key = st.nextToken();
						String value = st.nextToken();
						if (line.indexOf('"') > -1) {
							value = line.substring(line.indexOf('"')+1, line.lastIndexOf('"'));
						}
						list.add(new ItemAttribute(key, value, true));
						item.putAttributes(list);
					}
				}
				else if (cmd.equals("da") || cmd.equals("deleteattr")) {
					if (checkDomain(dom)) {
						if (st.countTokens() != 2) {
							System.out.println("Error: need item id and attribute name.");
							continue;
						}
						Item item = dom.getItem(st.nextToken());
						List<ItemAttribute> list = new ArrayList<ItemAttribute>();
						list.add(new ItemAttribute(st.nextToken(), null, true));
						item.deleteAttributes(list);
					}
				}
				else if (cmd.equals("di") || cmd.equals("deleteitem")) {
					if (checkDomain(dom)) {
						if (st.countTokens() != 1) {
							System.out.println("Error: need item id.");
							continue;
						}
						dom.deleteItem(st.nextToken());
					}
				}
				else if (cmd.equals("i") || cmd.equals("item")) {
					if (checkDomain(dom)) {
						if (st.countTokens() != 1) {
							System.out.println("Error: need item id.");
							continue;
						}
						Item item = dom.getItem(st.nextToken());
						List<ItemAttribute> attrs = item.getAttributes(new ArrayList<String>());
						System.out.println("Item : "+item.getIdentifier());
						for (ItemAttribute attr : attrs) {
							System.out.println(" "+attr.getName()+" = "+attr.getValue());
						}
					}
				}
				else if (cmd.equals("gi") || cmd.equals("getitems")) {
					if (checkDomain(dom)) {
						itemCount = 0;
						dom.setMaxThreads(20);
//						long start = System.currentTimeMillis();
						//dom.listItemsAttributes("", new ItemListener() {
						dom.listItemsWithAttributes("", null, new ItemListener() {
								public synchronized void itemAvailable(String id, List<ItemAttribute> attrs) {
									System.out.println("Item : "+id);
									for (ItemAttribute attr : attrs) {
										System.out.println("  "+attr.getName()+" = "+filter(attr.getValue()));
									}
									itemCount++;
								}
							});
//						long end = System.currentTimeMillis();
//						System.out.println("Time : "+((int)(end-start)/1000.0));
//						System.out.println("Number of items returned : "+itemCount);
					}
				}
				else if (cmd.equals("ga") || cmd.equals("getattributes")) {
					if (checkDomain(dom)) {
						itemCount = 0;
//						long start = System.currentTimeMillis();
						String nextToken = null;
						do {
							QueryWithAttributesResult qwar = dom.listItemsWithAttributes("", null, nextToken, 250);
							Map<String, List<ItemAttribute>> items = qwar.getItems();
							for (String id : items.keySet()) {
								System.out.println("Item : "+id);
								for (ItemAttribute attr : items.get(id)) {
									System.out.println("  "+attr.getName()+" = "+filter(attr.getValue()));
								}
								itemCount++;
							}
							nextToken = qwar.getNextToken();
						} while (nextToken != null && !nextToken.trim().equals(""));
//						long end = System.currentTimeMillis();
//						System.out.println("Time : "+((int)(end-start)/1000.0));
//						System.out.println("Number of items returned : "+itemCount);
					}
				}
				else if (cmd.equals("select")) {
					if (checkDomain(dom)) {
						itemCount = 0;
//						long start = System.currentTimeMillis();
						String nextToken = null;
						do {
							QueryWithAttributesResult qwar = dom.selectItems(line, nextToken);
							Map<String, List<ItemAttribute>> items = qwar.getItems();
							for (String id : items.keySet()) {
								System.out.println("Item : "+id);
								for (ItemAttribute attr : items.get(id)) {
									System.out.println("  "+attr.getName()+" = "+filter(attr.getValue()));
								}
								itemCount++;
							}
							nextToken = qwar.getNextToken();
							System.out.println("Box Usage :"+qwar.getBoxUsage());
						} while (nextToken != null && !nextToken.trim().equals(""));
//						long end = System.currentTimeMillis();
//						System.out.println("Time : "+((int)(end-start)/1000.0));
//						System.out.println("Number of items returned : "+itemCount);
					}
				}
				else if (cmd.equals("l") || cmd.equals("list")) {
					if (checkDomain(dom)) executeQuery(dom, null);
				}
				else {
					if (checkDomain(dom)) executeQuery(dom, line);
				}
			}
		} catch (Exception ex) {
			ex.printStackTrace();
			if (ex.getCause() != null) {
				System.err.println("caused by : ");
				ex.getCause().printStackTrace();
			}
		}
    }

	private static boolean checkDomain(Domain dom) {
		if (dom == null) {
			System.out.println("domain must be set!");
			return false;
		}
		return true;
	}

	private static void showHelp() {
		System.out.println("SimpleDB Shell Commands:");
		System.out.println("adddomain(ad) <domain name> : add new domain");
		System.out.println("deletedomain(dd) <domain name> : delete domain (not functional in SDS yet)");
		System.out.println("domains(d) : list domains");
		System.out.println("setdomain(sd) <domain name> : set current domain");
		System.out.println("domainmetadata(dm) : show current domain metadata");
		System.out.println("addattr(aa) <item id> <attr name> <attr value> : add attribute to item in current domain");
		System.out.println("replaceattr(ra) <item id> <attr name> <attr value> : replace attribute to item in current domain");
		System.out.println("deleteattr(da) <item id> <attr name> : delete attribute of item in current domain");
		System.out.println("deleteitem(di) <item id> : delete item in current domain");
		System.out.println("list(l) or <filter string> : lists items matching filter in current domain");
		System.out.println("item(i) <item id> : shows item attributes");
		System.out.println("select <expression> : runs a SQL like query against the domain specified");
		System.out.println("getitems(gi) : shows attributes for multiple items");
		System.out.println("help(h,?) : show help");
		System.out.println("quit(q) : exit the shell");
	}

		StringBuilder ret = new StringBuilder();
	private static String filter(String val) {
		if (val.length() == 0) return val;	// fast exit
		char [] chars = new char[val.length()];
		val.getChars(0, val.length(), chars, 0);
		for (int i=0; i<chars.length; i++) {
			if (!(chars[i]>0 && chars[i]<128)) {
				ret.append("\\u");
				ret.append(Integer.toHexString(chars[i]));
			}
			else {
				ret.append(chars[i]);
			}
		}
		return ret.toString();
	}
}