List of usage examples for com.amazonaws.services.simpledb.model UpdateCondition setExists
public void setExists(Boolean exists)
A value specifying whether or not the specified attribute must exist with the specified value in order for the update condition to be satisfied.
From source file:c3.ops.priam.aws.SDBInstanceData.java
License:Apache License
/** * Register a new instance. Registration will fail if a prior entry exists * * @param instance/*w ww. java 2s. c o m*/ * @throws AmazonServiceException */ public void registerInstance(PriamInstance instance) throws AmazonServiceException { AmazonSimpleDBClient simpleDBClient = getSimpleDBClient(); PutAttributesRequest putReq = new PutAttributesRequest(DOMAIN, getKey(instance), createAttributesToRegister(instance)); UpdateCondition expected = new UpdateCondition(); expected.setName(Attributes.INSTANCE_ID); expected.setExists(false); putReq.setExpected(expected); simpleDBClient.putAttributes(putReq); }
From source file:com.aipo.aws.simpledb.SimpleDB.java
License:Open Source License
private static Integer counterJob(String domain) { AmazonSimpleDB client = getClient(); GetAttributesRequest getAttributesRequest = new GetAttributesRequest(); getAttributesRequest.setDomainName(DEFAULT_COUNTER_DOMAIN); getAttributesRequest.setItemName(domain); getAttributesRequest.setConsistentRead(true); Integer count = null;// ww w . j a va 2s. c o m try { GetAttributesResult attributes = client.getAttributes(getAttributesRequest); List<Attribute> list = attributes.getAttributes(); for (Attribute item : list) { if ("c".equals(item.getName())) { try { count = Integer.valueOf(item.getValue()); } catch (Throwable ignore) { } } } } catch (Throwable t) { t.printStackTrace(); } if (count == null) { CreateDomainRequest createDomainRequest = new CreateDomainRequest(DEFAULT_COUNTER_DOMAIN); client.createDomain(createDomainRequest); count = 0; } int next = count + 1; PutAttributesRequest putAttributesRequest = new PutAttributesRequest(); putAttributesRequest.setDomainName(DEFAULT_COUNTER_DOMAIN); putAttributesRequest.setItemName(domain); List<ReplaceableAttribute> attr = new ArrayList<ReplaceableAttribute>(); attr.add(new ReplaceableAttribute("c", String.valueOf(next), true)); putAttributesRequest.setAttributes(attr); UpdateCondition updateCondition = new UpdateCondition(); if (next == 1) { updateCondition.setExists(false); updateCondition.setName("c"); } else { updateCondition.setExists(true); updateCondition.setName("c"); updateCondition.setValue(String.valueOf(count)); } putAttributesRequest.setExpected(updateCondition); client.putAttributes(putAttributesRequest); return next; }
From source file:squash.booking.lambdas.core.OptimisticPersister.java
License:Apache License
@Override public int put(String itemName, Optional<Integer> version, ReplaceableAttribute attribute) throws Exception { if (!initialised) { throw new IllegalStateException("The optimistic persister has not been initialised"); }//from www .j av a 2 s . co m logger.log("About to add attrbutes to simpledb item: " + itemName); AmazonSimpleDB client = getSimpleDBClient(); // Check the put will not take us over the maximum number of attributes: // N.B. if (replace == true) then this check could be over-eager, but not // worth refining it, since this effectively just alters the limit by one. ImmutablePair<Optional<Integer>, Set<Attribute>> versionedAttributes = get(itemName); if (versionedAttributes.left.isPresent()) { logger.log("Retrieved versioned attributes(Count: " + versionedAttributes.right.size() + ") have version number: " + versionedAttributes.left.get()); } else { // There should be no attributes in this case. logger.log("Retrieved versioned attributes(Count: " + versionedAttributes.right.size() + ") have no version number"); } Boolean tooManyAttributes = versionedAttributes.right.size() >= maxNumberOfAttributes; if (tooManyAttributes && !attribute.getValue().startsWith("Inactive")) { // We allow puts to inactivate attributes even when on the limit - // otherwise we could never delete when we're on the limit. logger.log("Cannot create attribute - the maximum number of attributes already exists (" + maxNumberOfAttributes + ") so throwing a 'Database put failed - too many attributes' exception"); throw new Exception("Database put failed - too many attributes"); } // Do a conditional put - so we don't overwrite someone else's attributes UpdateCondition updateCondition = new UpdateCondition(); updateCondition.setName(versionAttributeName); ReplaceableAttribute versionAttribute = new ReplaceableAttribute(); versionAttribute.setName(versionAttributeName); versionAttribute.setReplace(true); // Update will proceed unless the version number has changed if (version.isPresent()) { // A version number attribute exists - so it should be unchanged updateCondition.setValue(Integer.toString(version.get())); // Bump up our version number attribute versionAttribute.setValue(Integer.toString(version.get() + 1)); } else { // A version number attribute did not exist - so it still should not updateCondition.setExists(false); // Set initial value for our version number attribute versionAttribute.setValue("0"); } List<ReplaceableAttribute> replaceableAttributes = new ArrayList<>(); replaceableAttributes.add(versionAttribute); // Add the new attribute replaceableAttributes.add(attribute); PutAttributesRequest simpleDBPutRequest = new PutAttributesRequest(simpleDbDomainName, itemName, replaceableAttributes, updateCondition); try { client.putAttributes(simpleDBPutRequest); } catch (AmazonServiceException ase) { if (ase.getErrorCode().contains("ConditionalCheckFailed")) { // Someone else has mutated an attribute since we read them. This is // likely to be rare, and a retry should almost always succeed. However, // we leave it to clients of this class to retry the call if they wish, // as the new mutation may mean they no longer want to do the put. logger.log("Caught AmazonServiceException for ConditionalCheckFailed whilst creating" + " attribute(s) so throwing as 'Database put failed' instead"); throw new Exception("Database put failed - conditional check failed"); } throw ase; } logger.log("Created attribute(s) in simpledb"); return Integer.parseInt(versionAttribute.getValue()); }
From source file:squash.booking.lambdas.core.OptimisticPersister.java
License:Apache License
@Override public void delete(String itemName, Attribute attribute) throws Exception { if (!initialised) { throw new IllegalStateException("The optimistic persister has not been initialised"); }/*from w w w .j av a2 s . co m*/ logger.log("About to delete attribute from simpledb item: " + itemName); AmazonSimpleDB client = getSimpleDBClient(); // We retry the delete if necessary if we get a // ConditionalCheckFailed exception, i.e. if someone else modifies the // database between us reading and writing it. RetryHelper.DoWithRetries(() -> { try { // Get existing attributes (and version number), via consistent // read: ImmutablePair<Optional<Integer>, Set<Attribute>> versionedAttributes = get(itemName); if (!versionedAttributes.left.isPresent()) { logger.log( "A version number attribute did not exist - this means no attributes exist, so we have nothing to delete."); return null; } if (!versionedAttributes.right.contains(attribute)) { logger.log("The attribute did not exist - so we have nothing to delete."); return null; } // Since it seems impossible to update the version number while // deleting an attribute, we first mark the attribute as inactive, // and then delete it. ReplaceableAttribute inactiveAttribute = new ReplaceableAttribute(); inactiveAttribute.setName(attribute.getName()); inactiveAttribute.setValue("Inactive" + attribute.getValue()); inactiveAttribute.setReplace(true); put(itemName, versionedAttributes.left, inactiveAttribute); // Now we can safely delete the attribute, as other readers will now // ignore it. UpdateCondition updateCondition = new UpdateCondition(); updateCondition.setName(inactiveAttribute.getName()); updateCondition.setValue(inactiveAttribute.getValue()); // Update will proceed unless the attribute no longer exists updateCondition.setExists(true); Attribute attributeToDelete = new Attribute(); attributeToDelete.setName(inactiveAttribute.getName()); attributeToDelete.setValue(inactiveAttribute.getValue()); List<Attribute> attributesToDelete = new ArrayList<>(); attributesToDelete.add(attributeToDelete); DeleteAttributesRequest simpleDBDeleteRequest = new DeleteAttributesRequest(simpleDbDomainName, itemName, attributesToDelete, updateCondition); client.deleteAttributes(simpleDBDeleteRequest); logger.log("Deleted attribute from simpledb"); return null; } catch (AmazonServiceException ase) { if (ase.getErrorCode().contains("AttributeDoesNotExist")) { // Case of trying to delete an attribute that no longer exists - // that's ok - it probably just means more than one person was // trying to delete the attribute at once. So swallow this // exception logger.log( "Caught AmazonServiceException for AttributeDoesNotExist whilst deleting attribute so" + " swallowing and continuing"); return null; } else { throw ase; } } }, Exception.class, Optional.of("Database put failed - conditional check failed"), logger); }
From source file:wwutil.jsoda.SimpleDBService.java
License:Mozilla Public License
private UpdateCondition buildExpectedValue(String modelName, String expectedField, Object expectedValue, boolean expectedExists) throws Exception { if (expectedValue == null) throw new IllegalArgumentException("ExpectedValue cannot be null."); String attrName = jsoda.getFieldAttrMap(modelName).get(expectedField); String fieldValue = DataUtil.encodeValueToAttrStr(expectedValue, jsoda.getField(modelName, expectedField).getType()); UpdateCondition cond = new UpdateCondition(); cond.setExists(expectedExists); cond.setName(attrName);/*from w w w . j av a2s . com*/ if (expectedExists) { cond.setValue(fieldValue); } return cond; }