@Override
    public void save(String siddhiAppId, String revision, byte[] data) {
        Map<String, byte[]> executionPersistenceMap = persistenceMap.get(siddhiAppId);
        if (executionPersistenceMap == null) {
            executionPersistenceMap = new HashMap<String, byte[]>();
        }
        executionPersistenceMap.put(revision, data);
        List<String> revisionList = revisionMap.get(siddhiAppId);
        if (revisionList == null) {
            revisionList = new ArrayList<String>();
            revisionMap.put(siddhiAppId, revisionList);
        }
        if (revisionList.size() == 0 || (revisionList.size() > 0 && !revision.equals(revisionList.get(
                revisionList.size() - 1)))) {
            revisionList.add(revision);
            revisionMap.put(siddhiAppId, revisionList);
        }
        persistenceMap.put(siddhiAppId, executionPersistenceMap);


    }
Implementation of {@link PersistenceStore} which will store the state in-memory.
modules/siddhi-core/src/main/java/io/siddhi/core/util/persistence/InMemoryPersistenceStore.java