Transaction Support

src/main/java/org/fcrepo/client/FcrepoClient.java

@@ -16,6 +16,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.TreeMap;
+import java.util.regex.Pattern;
 
 import org.apache.http.Header;
 import org.apache.http.HttpEntity;
@@ -52,6 +53,8 @@ public class FcrepoClient implements Closeable {
 
     private Boolean throwExceptionOnFailure = true;
 
+    public static final String TRANSACTION_ENDPOINT = "fcr:tx";
+
     private static final Logger LOGGER = getLogger(FcrepoClient.class);
 
     /**
@@ -166,12 +169,35 @@ public HistoricMementoBuilder createMemento(final URI url, final String mementoD
     }
 
     /**
-     * Interact with the Transaction API - start, commit, etc
+     * Start a transaction and create a new {@link TransactionalFcrepoClient}
      *
-     * @return a transaction request builder object
+     * @param uri the base rest endpoint or the transaction endpoint
+     * @return the TransactionalFcrepoClient
+     * @throws IOException if there's an error with the http request
+     * @throws IllegalArgumentException if the uri is not the Fedora transaction endpoint
+     * @throws FcrepoOperationFailedException if there's an error in the fcrepo operation
      */
-    public TransactionBuilder transaction() {
-        return new TransactionBuilder(this);
+    public TransactionalFcrepoClient startTransactionClient(final URI uri)
+        throws IOException, FcrepoOperationFailedException {
+        final var target = getTxEndpoint(uri);
+        try (final var response = post(target).perform()) {
+            return transactionalClient(response.getTransactionUri());
+        }
+    }
+
+    private URI getTxEndpoint(final URI uri) {
+        final var isRoot = Pattern.compile("rest/?$").asPredicate();
+        final var isTx = Pattern.compile("rest/" + TRANSACTION_ENDPOINT + "/?$").asPredicate();
+        final var base = uri.toString();
+        if (isRoot.test(base)) {
+            LOGGER.debug("Start transaction request matches root, appending {}", TRANSACTION_ENDPOINT);
+            // preface with ./ so fcr:tx isn't interpreted as a scheme
+            return uri.resolve("./" + TRANSACTION_ENDPOINT);
+        } else if (isTx.test(base)) {
+            return uri;
+        } else {
+            throw new IllegalArgumentException("Uri is not the base rest endpoint or the transaction endpoint");
+        }
     }
 
     /**

src/main/java/org/fcrepo/client/FcrepoResponse.java

@@ -7,8 +7,8 @@
 
 import static java.util.Collections.emptyList;
 import static java.util.stream.Collectors.toList;
+import static org.fcrepo.client.FcrepoClient.TRANSACTION_ENDPOINT;
 import static org.fcrepo.client.FedoraHeaderConstants.ATOMIC_ID;
-import static org.fcrepo.client.TransactionBuilder.TRANSACTION_ENDPOINT;
 import static org.fcrepo.client.FedoraHeaderConstants.CONTENT_DISPOSITION;
 import static org.fcrepo.client.FedoraHeaderConstants.CONTENT_TYPE;
 import static org.fcrepo.client.FedoraHeaderConstants.LINK;

src/main/java/org/fcrepo/client/TransactionalFcrepoClient.java

@@ -7,8 +7,11 @@
 
 import java.net.URI;
 
+import org.apache.http.client.methods.HttpRequestBase;
+
 /**
- * A Transaction aware client which adds the Atomic_ID header to requests
+ * A Transaction aware client which adds the Atomic_ID header to requests and provides functionality for interacting
+ * with the Fedora Transaction API
  *
  * @author mikejritter
  */
@@ -38,43 +41,59 @@ public FcrepoResponse.TransactionURI getTransactionURI() {
     }
 
     /**
-     * A shorthand for calling {@link TransactionBuilder#commit(FcrepoResponse.TransactionURI)} with the URI of the
-     * TransactionalFcrepoClient
+     * Commit a transaction by performing a PUT
      *
      * @return the commit RequestBuilder
      */
-    public RequestBuilder transactionCommit() {
-        return transaction().commit(transactionURI);
+    public RequestBuilder commit() {
+        return new RequestBuilder(transactionURI.get(), this) {
+            @Override
+            protected HttpRequestBase createRequest() {
+                return HttpMethods.PUT.createRequest(targetUri);
+            }
+        };
     }
 
     /**
-     * A shorthand for calling {@link TransactionBuilder#status(FcrepoResponse.TransactionURI)} with the URI of the
-     * TransactionalFcrepoClient
+     * Retrieve the status of a transaction by performing a GET
      *
      * @return the status RequestBuilder
      */
-    public RequestBuilder transactionStatus() {
-        return transaction().status(transactionURI);
+    public RequestBuilder status() {
+        return new RequestBuilder(transactionURI.get(), this) {
+            @Override
+            protected HttpRequestBase createRequest() {
+                return HttpMethods.GET.createRequest(targetUri);
+            }
+        };
     }
 
     /**
-     * A shorthand for calling {@link TransactionBuilder#keepAlive(FcrepoResponse.TransactionURI)} with the URI of the
-     * TransactionalFcrepoClient
+     * Keep a transaction alive by performing a POST
      *
      * @return the keep alive RequestBuilder
      */
-    public RequestBuilder transactionKeepAlive() {
-        return transaction().keepAlive(transactionURI);
+    public RequestBuilder keepAlive() {
+        return new RequestBuilder(transactionURI.get(), this) {
+            @Override
+            protected HttpRequestBase createRequest() {
+                return HttpMethods.POST.createRequest(targetUri);
+            }
+        };
     }
 
     /**
-     * A shorthand for calling {@link TransactionBuilder#rollback(FcrepoResponse.TransactionURI)} with the URI of the
-     * TransactionalFcrepoClient
+     * Rollback a transaction by performing a DELETE
      *
      * @return the rollback RequestBuilder
      */
-    public RequestBuilder transactionRollback() {
-        return transaction().rollback(transactionURI);
+    public RequestBuilder rollback() {
+        return new RequestBuilder(transactionURI.get(), this) {
+            @Override
+            protected HttpRequestBase createRequest() {
+                return HttpMethods.DELETE.createRequest(targetUri);
+            }
+        };
     }
 
     @Override