Introduced the "allocationId" to EC2's notion of an IP Address so that the describeAddresssesInRegion method of the IP Client will contain this information.

apis/ec2/src/main/java/org/jclouds/ec2/domain/PublicIpInstanceIdPair.java

@@ -34,13 +34,15 @@ public class PublicIpInstanceIdPair implements Comparable<PublicIpInstanceIdPair
    private final String region;
    @Nullable
    private final String instanceId;
+   private final String allocationId;
    private final String publicIp;
    private final Map<String, String> tags;
 
    public PublicIpInstanceIdPair(final String region, final String publicIp, @Nullable final String instanceId,
-         @Nullable final Map<String, String> tags) {
+         @Nullable final String allocationId, @Nullable final Map<String, String> tags) {
       this.region = checkNotNull(region, "region");
       this.instanceId = instanceId;
+      this.allocationId = allocationId;
       this.publicIp = checkNotNull(publicIp, "publicIp");
       this.tags = tags == null ? ImmutableMap.<String, String> of() : ImmutableMap.copyOf(tags);
    }
@@ -71,6 +73,13 @@ public class PublicIpInstanceIdPair implements Comparable<PublicIpInstanceIdPair
       return instanceId;
    }
 
+   /**
+    * The ID of the IP allocation (e.g., eipalloc-0ca038968f2a2c986).
+    */
+   public String getAllocationId() {
+      return allocationId;
+   }
+
    /**
     * The public IP address.
     */
@@ -87,6 +96,7 @@ public class PublicIpInstanceIdPair implements Comparable<PublicIpInstanceIdPair
       final int prime = 31;
       int result = 1;
       result = prime * result + ((instanceId == null) ? 0 : instanceId.hashCode());
+      result = prime * result + ((allocationId == null) ? 0 : allocationId.hashCode());
       result = prime * result + ((publicIp == null) ? 0 : publicIp.hashCode());
       result = prime * result + ((region == null) ? 0 : region.hashCode());
       result = prime * result + ((tags == null) ? 0 : tags.hashCode());
@@ -107,6 +117,11 @@ public class PublicIpInstanceIdPair implements Comparable<PublicIpInstanceIdPair
             return false;
       } else if (!instanceId.equals(other.instanceId))
          return false;
+      if (allocationId == null) {
+         if (other.allocationId != null)
+            return false;
+      } else if (!allocationId.equals(other.allocationId))
+         return false;
       if (publicIp == null) {
          if (other.publicIp != null)
             return false;

apis/ec2/src/main/java/org/jclouds/ec2/features/ElasticIPAddressApi.java

@@ -144,6 +144,28 @@ public interface ElasticIPAddressApi {
             @EndpointParam(parser = RegionToEndpointOrProviderIfNull.class) @Nullable String region,
             @FormParam("PublicIp") String publicIp);
 
+   /**
+    * Releases an elastic IP address associated with your identity.
+    *
+    * @param region
+    *           Elastic IP addresses are tied to a Region and cannot be mapped across Regions.
+    * @param allocationId
+    *           The Allocation ID (e.g., eipalloc-0ca038968f2a2c986) of the IP address that you are releasing from your identity.
+    *
+    * @see #allocateAddress
+    * @see #describeAddresses
+    * @see #associateAddress
+    * @see #disassociateAddress
+    * @see <a href="http://docs.amazonwebservices.com/AWSEC2/latest/APIReference/index.html?ApiReference-query-ReleaseAddress.html"
+    */
+   @Named("ReleaseAddress")
+   @POST
+   @Path("/")
+   @FormParams(keys = ACTION, values = "ReleaseAddress")
+   void releaseAddressInRegionByAllocationId(
+           @EndpointParam(parser = RegionToEndpointOrProviderIfNull.class) @Nullable String region,
+           @FormParam("AllocationId") String allocationId);
+
    /**
     * Lists elastic IP addresses assigned to your identity or provides information about a specific
     * address.

apis/ec2/src/main/java/org/jclouds/ec2/xml/DescribeAddressesResponseHandler.java

@@ -44,6 +44,7 @@ public class DescribeAddressesResponseHandler extends HandlerForGeneratedRequest
    @Inject
    @Region
    Supplier<String> defaultRegion;
+   private String allocationId;
    private String instanceId;
    private final TagSetHandler tagSetHandler;
    private boolean inTagSet;
@@ -80,14 +81,17 @@ public class DescribeAddressesResponseHandler extends HandlerForGeneratedRequest
          ipAddress = currentOrNull();
       } else if (qName.equals("instanceId")) {
          instanceId = currentOrNull();
+      } else if (qName.equals("allocationId")) {
+         allocationId = currentOrNull();
       } else if (qName.equals("item")) {
          String region = AWSUtils.findRegionInArgsOrNull(getRequest());
          if (region == null)
             region = defaultRegion.get();
 
-         pairs.add(new PublicIpInstanceIdPair(region, ipAddress, instanceId, tagResults));
+         pairs.add(new PublicIpInstanceIdPair(region, ipAddress, instanceId, allocationId, tagResults));
          ipAddress = null;
          instanceId = null;
+         allocationId = null;
          tagResults = null;
       }
 

apis/ec2/src/test/java/org/jclouds/ec2/compute/loaders/LoadPublicIpForInstanceOrNullTest.java

@@ -41,7 +41,7 @@ public class LoadPublicIpForInstanceOrNullTest {
 
       expect(client.getElasticIPAddressApi()).andReturn((Optional) Optional.of(ipClient)).atLeastOnce();
       expect(ipClient.describeAddressesInRegion("region")).andReturn(
-            ImmutableSet.<PublicIpInstanceIdPair> of(new PublicIpInstanceIdPair("region", "1.1.1.1", "i-blah", null)))
+            ImmutableSet.<PublicIpInstanceIdPair> of(new PublicIpInstanceIdPair("region", "1.1.1.1", "i-blah", null, null)))
             .atLeastOnce();
 
       replay(client);
@@ -85,7 +85,7 @@ public class LoadPublicIpForInstanceOrNullTest {
       expect(client.getElasticIPAddressApi()).andReturn((Optional) Optional.of(ipClient)).atLeastOnce();
 
       expect(ipClient.describeAddressesInRegion("region")).andReturn(
-            ImmutableSet.<PublicIpInstanceIdPair> of(new PublicIpInstanceIdPair("region", "1.1.1.1", null, null)))
+            ImmutableSet.<PublicIpInstanceIdPair> of(new PublicIpInstanceIdPair("region", "1.1.1.1", null, null, null)))
                .atLeastOnce();
 
       replay(client);