A brief example of how Conditional Mutations work in Accumulo 1.6.0.

ConditionalWriterExample.java

public void conditionalWrite(String docId, ColumnVisibility cv, Connector conn) throws Exception {
  // setup writer
  String tablename = "table";

  ConditionalWriterConfig cwConfig = new ConditionalWriterConfig();
  cwConfig.setAuthorizations(new Authorizations("a","b","c"));
  ConditionalWriter cw = conn.createConditionalWriter(tablename, cwConfig);

  // set up condition on this mutation
  IteratorSetting is = new IteratorSetting(1, SuppressCVIterator.class);
  Condition condition = new Condition("docId", new Text(docId));
  condition.setIterators(is);

  // document mutations
  ConditionalMutation m = new ConditionalMutation(type.getId(), condition);
  m.put("docId", docId, cv, new Value("".getBytes()));
  m.put("meta", "meta1", cv, new Value("v1"));
  m.put("meta", "meta2", cv, new Value("v2"));
  m.put("meta", "meta3", cv, new Value("v3"));

  // send mutation and check status
  Status status = cw.write(docMutation).getStatus();
  switch (status) {
    case ACCEPTED:
        break;
    case REJECTED:
        throw new RuntimeException("Document already exists (rejected).");
    case UNKNOWN:
        throw new RuntimeException("Document may already exist or be written. Resent mutation.");
    default:
      throw new RuntimeException("Unexpected status " + status);
  }
}