Added BEGIN/COMMIT/ROLLBACK

shell/CHANGES.txt

@@ -1,3 +1,7 @@
+1.8.M03
+--------------------
+o Added BEGIN TRANSACTION/COMMIT/ROLLBACK
+
 1.8.M02 (2012-05-11)
 --------------------
 o Shell can now be exited with Ctrl-D

shell/src/docs/dev/shell.txt

@@ -247,6 +247,17 @@ Example: +index -i persons name+ (will index the name for the current node or re
 * +-i+ will index a key-value pair in an index for the current node/relationship. If no value is given the property value for that key for the current node is used as value.
 * +-r+ will remove a key-value pair (if it exists) from an index for the current node/relationship. Key and value is optional. 
 
+=== Transactions ===
+It is useful to be able to test changes, and then being able to commit or rollback said changes.
+
+Transactions can be nested. With a nested transaction, a commit does not write any changes to disk, except for the
+top level transaction. A rollback, however works regardless of the level of the transaction. It will roll back
+all open transactions.
+
+* +begin transaction+  Starts a transaction.
+* +commit+ Commits a transaction.
+* +rollback+ Rollbacks all open transactions.
+
 [[shell-extending]]
 == Extending the shell: Adding your own commands ==
 

shell/src/main/java/org/neo4j/shell/kernel/apps/Begin.java

@@ -0,0 +1,84 @@
+/**
+ * Copyright (c) 2002-2012 "Neo Technology,"
+ * Network Engine for Objects in Lund AB [http://neotechnology.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Neo4j is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.neo4j.shell.kernel.apps;
+
+import java.rmi.RemoteException;
+
+import javax.transaction.SystemException;
+import javax.transaction.Transaction;
+
+import org.neo4j.helpers.Service;
+import org.neo4j.kernel.AbstractGraphDatabase;
+import org.neo4j.shell.App;
+import org.neo4j.shell.AppCommandParser;
+import org.neo4j.shell.Output;
+import org.neo4j.shell.Session;
+import org.neo4j.shell.ShellException;
+import org.neo4j.shell.kernel.GraphDatabaseShellServer;
+
+@Service.Implementation(App.class)
+public class Begin extends ReadOnlyGraphDatabaseApp
+{
+    @Override
+    public String getDescription()
+    {
+        return "Opens a transaction";
+    }
+
+    @Override
+    protected String exec( AppCommandParser parser, Session session, Output out )
+            throws ShellException, RemoteException
+    {
+        Transaction tx = currentTransaction( getServer() );
+
+        getServer().getDb().beginTx();
+        Integer txCount = (Integer) session.get( "tx_count" );
+
+        int count;
+        if ( txCount == null )
+        {
+            if ( tx == null )
+            {
+                count = 0;
+            } else
+            {
+                count = 1;
+            }
+        } else
+        {
+            count = txCount;
+        }
+
+        session.set( "tx_count", ++count );
+        out.println("Transaction started");
+        return null;
+    }
+
+    public static Transaction currentTransaction( GraphDatabaseShellServer server ) throws ShellException
+    {
+        try
+        {
+            return ((AbstractGraphDatabase) server.getDb()).getTxManager().getTransaction();
+        } catch ( SystemException e )
+        {
+            throw new ShellException( e.getMessage() );
+        }
+    }
+}

shell/src/main/java/org/neo4j/shell/kernel/apps/Commit.java

@@ -0,0 +1,93 @@
+/**
+ * Copyright (c) 2002-2012 "Neo Technology,"
+ * Network Engine for Objects in Lund AB [http://neotechnology.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Neo4j is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.neo4j.shell.kernel.apps;
+
+import java.rmi.RemoteException;
+
+import javax.transaction.SystemException;
+import javax.transaction.Transaction;
+
+import org.neo4j.helpers.Service;
+import org.neo4j.kernel.AbstractGraphDatabase;
+import org.neo4j.shell.App;
+import org.neo4j.shell.AppCommandParser;
+import org.neo4j.shell.Output;
+import org.neo4j.shell.Session;
+import org.neo4j.shell.ShellException;
+
+@Service.Implementation(App.class)
+public class Commit extends ReadOnlyGraphDatabaseApp
+{
+    public static final String tx_count = "tx_count";
+
+    @Override
+    public String getDescription()
+    {
+        return "Commits a transaction";
+    }
+
+    @Override
+    protected String exec( AppCommandParser parser, Session session, Output out )
+            throws ShellException, RemoteException
+    {
+        Integer txCount = (Integer) session.get( tx_count );
+
+        if ( txCount == null || txCount.equals( 0 ) )
+        {
+            throw new ShellException( "Not in a transaction" );
+        } else if ( txCount.equals( 1 ) )
+        {
+            Transaction tx;
+            try
+            {
+                tx = ((AbstractGraphDatabase) getServer().getDb()).getTxManager().getTransaction();
+                if ( tx == null )
+                {
+                    throw fail( session, "Not in a transaction" );
+                }
+            } catch ( SystemException e )
+            {
+                throw fail( session, "Not in a transaction" );
+            }
+
+            try
+            {
+                tx.commit();
+                session.remove( tx_count );
+                out.println("Transaction committed");
+                return null;
+            } catch ( Exception e )
+            {
+                throw fail( session, e.getMessage() );
+            }
+        } else
+        {
+            session.set( tx_count, --txCount );
+            out.println("Transaction committed");
+            return null;
+        }
+    }
+
+    public static ShellException fail( Session session, String message ) throws ShellException
+    {
+        session.remove( tx_count );
+        return new ShellException( message );
+    }
+}

shell/src/main/java/org/neo4j/shell/kernel/apps/Rollback.java

@@ -0,0 +1,64 @@
+/**
+ * Copyright (c) 2002-2012 "Neo Technology,"
+ * Network Engine for Objects in Lund AB [http://neotechnology.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Neo4j is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.neo4j.shell.kernel.apps;
+
+import java.rmi.RemoteException;
+
+import javax.transaction.SystemException;
+import javax.transaction.Transaction;
+
+import org.neo4j.helpers.Service;
+import org.neo4j.shell.App;
+import org.neo4j.shell.AppCommandParser;
+import org.neo4j.shell.Output;
+import org.neo4j.shell.Session;
+import org.neo4j.shell.ShellException;
+
+@Service.Implementation(App.class)
+public class Rollback extends ReadOnlyGraphDatabaseApp
+{
+    @Override
+    public String getDescription()
+    {
+        return "Rolls back all open transactions";
+    }
+
+    @Override
+    protected String exec( AppCommandParser parser, Session session, Output out )
+            throws ShellException, RemoteException
+    {
+        Transaction tx = Begin.currentTransaction( getServer() );
+        if ( tx == null )
+        {
+            throw Commit.fail( session, "Not in a transaction" );
+        } else
+        {
+            try
+            {
+                tx.rollback();
+                out.println("Transaction rolled back");
+                return null;
+            } catch ( SystemException e )
+            {
+                throw new ShellException( e.getMessage() );
+            }
+        }
+    }
+}

shell/src/main/resources/META-INF/services/org.neo4j.shell.App

@@ -3,7 +3,9 @@ org.neo4j.shell.apps.Env
 org.neo4j.shell.apps.Export
 org.neo4j.shell.apps.Help
 org.neo4j.shell.apps.Man
+org.neo4j.shell.kernel.apps.Begin
 org.neo4j.shell.kernel.apps.Cd
+org.neo4j.shell.kernel.apps.Commit
 org.neo4j.shell.kernel.apps.Create
 org.neo4j.shell.kernel.apps.Cypher
 org.neo4j.shell.kernel.apps.Ls
@@ -15,6 +17,7 @@ org.neo4j.shell.kernel.apps.Start
 org.neo4j.shell.kernel.apps.Rm
 org.neo4j.shell.kernel.apps.Rmrel
 org.neo4j.shell.kernel.apps.Rmnode
+org.neo4j.shell.kernel.apps.Rollback
 org.neo4j.shell.kernel.apps.Set
 org.neo4j.shell.kernel.apps.Trav
 org.neo4j.shell.kernel.apps.Index