Transaction Support

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

@@ -51,6 +51,8 @@ public class FcrepoClient implements Closeable {
 
     private Boolean throwExceptionOnFailure = true;
 
+    private static final String TRANSACTION_ENDPOINT = "fcr:tx";
+
     private static final Logger LOGGER = getLogger(FcrepoClient.class);
 
     /**
@@ -152,6 +154,17 @@ public HistoricMementoBuilder createMemento(final URI url, final String mementoD
         return new HistoricMementoBuilder(url, this, mementoDatetime);
     }
 
+    /**
+     * Make a POST request to create a new Transaction
+     *
+     * @param url the base url of the Fedora repository
+     * @return ???
+     */
+    public PostBuilder startTransaction(final URI url) {
+        final var txUrl = url.resolve(TRANSACTION_ENDPOINT);
+        return post(txUrl);
+    }
+
     /**
      * Make a DELETE request to delete a resource
      *

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

@@ -56,6 +56,8 @@ public class FcrepoResponse implements Closeable {
 
     private InputStream body;
 
+    private String transactionUri;
+
     private String contentType;
 
     private boolean closed = false;
@@ -313,4 +315,18 @@ public Map<String, String> getContentDisposition() {
         }
         return contentDisposition;
     }
+
+    /**
+     * Get the transaction location. If the location is not for a transaction, return null.
+     *
+     * @return the transaction location or null
+     */
+    public String getTransactionUri() {
+        if (transactionUri == null && headers.containsKey(LOCATION)) {
+            final var location = getHeaderValue(LOCATION);
+            transactionUri = location.contains("fcr:tx") ? location : null;
+        }
+
+        return transactionUri;
+    }
 }

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

@@ -67,6 +67,10 @@ public class FedoraHeaderConstants {
 
     public static final String ACCEPT_DATETIME = "Accept-Datetime";
 
+    public static final String ATOMIC_ID = "Atomic-Id";
+
+    public static final String ATOMIC_EXPIRES = "Atomic-Expires";
+
     private FedoraHeaderConstants() {
     }
 }

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

@@ -45,4 +45,9 @@ public HistoricMementoBuilder(final URI uri, final FcrepoClient client, final St
         UTC_RFC_1123_FORMATTER.parse(mementoDatetime);
         request.setHeader(MEMENTO_DATETIME, mementoDatetime);
     }
+
+    @Override
+    public RequestBuilder addTransaction(final String transaction) {
+        throw new IllegalStateException("Mementos are not allowed in transactions");
+    }
 }

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

@@ -40,4 +40,9 @@ public OriginalMementoBuilder addHeader(final String name, final String value) {
     public OriginalMementoBuilder addLinkHeader(final FcrepoLink linkHeader) {
         return (OriginalMementoBuilder) super.addLinkHeader(linkHeader);
     }
+
+    @Override
+    public RequestBuilder addTransaction(final String transaction) {
+        throw new IllegalStateException("Mementos are not allowed in transactions");
+    }
 }

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

@@ -5,6 +5,7 @@
  */
 package org.fcrepo.client;
 
+import static org.fcrepo.client.FedoraHeaderConstants.ATOMIC_ID;
 import static org.slf4j.LoggerFactory.getLogger;
 import static org.fcrepo.client.FedoraHeaderConstants.LINK;
 
@@ -89,4 +90,15 @@ protected RequestBuilder addLinkHeader(final FcrepoLink linkHeader) {
         request.addHeader(LINK, linkHeader.toString());
         return this;
     }
+
+    /**
+     * Add a transaction atomic id header to the request
+     *
+     * @param transaction transaction atomic id
+     * @return this builder
+     */
+    public RequestBuilder addTransaction(final String transaction) {
+        request.addHeader(ATOMIC_ID, transaction);
+        return this;
+    }
 }