Start implementing MasterProposer.

2 files changed, 135 insertions, 0 deletions

diff --git a/same/src/main/java/com/orbekk/paxos/MasterProposer.java b/same/src/main/java/com/orbekk/paxos/MasterProposer.java
new file mode 100644
index 0000000..c33cf68
--- /dev/null
+++ b/same/src/main/java/com/orbekk/paxos/MasterProposer.java
@@ -0,0 +1,77 @@
+package com.orbekk.paxos;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.orbekk.same.ConnectionManager;
+
+public class MasterProposer implements Runnable {
+    private String myUrl;
+    private int roundId = 0;
+    private int proposalNumber = 0;
+    private List<String> paxosUrls = new ArrayList<String>();
+    private Runnable roundFailedAction;
+    private Runnable masterAction;
+    private ConnectionManager connections;
+    
+    public static Runnable getTimeoutAction(final long milliseconds) {
+        return new Runnable() {
+            @Override public void run() {
+                try {
+                    Thread.sleep(milliseconds);
+                } catch (InterruptedException e) {
+                    // Ignore interrupts.
+                }
+            }
+        };
+    }
+    
+    MasterProposer(String clientUrl, List<String> paxosUrls, int roundId,
+            ConnectionManager connections, Runnable roundFailedAction,
+            Runnable masterAction) {
+        this.myUrl = clientUrl;
+        this.paxosUrls = paxosUrls;
+        this.roundId = roundId;
+        this.connections = connections;
+        this.roundFailedAction = roundFailedAction;
+        this.masterAction = masterAction;
+    }
+    
+    private boolean propose(int roundId, int proposalNumber) {
+        int promises = 0;
+        for (String url : paxosUrls) {
+            PaxosService paxos = connections.getPaxos(url);
+            boolean success = paxos.propose(myUrl, roundId, proposalNumber);
+            if (success) {
+                promises += 1;
+            }
+        }
+        return promises > paxosUrls.size() / 2;
+    }
+    
+    private boolean acceptRequest(int roundId, int proposalNumber) {
+        int accepts = 0;
+        for (String url : paxosUrls) {
+            PaxosService paxos = connections.getPaxos(url);
+            boolean success = paxos.acceptRequest(myUrl, roundId, proposalNumber);
+            if (success) {
+                accepts += 1;
+            }
+        }
+        return accepts > paxosUrls.size() / 2;        
+    }
+    
+    @Override public void run() {
+        boolean success = false;
+        success = propose(roundId + 1, proposalNumber + 1);
+        if (success) {
+            success = acceptRequest(roundId + 1, proposalNumber + 1);
+        }
+        if (success) {
+            masterAction.run();
+        } else {
+            roundFailedAction.run();
+            // TODO: Next round?
+        }
+    }
+}
diff --git a/same/src/test/java/com/orbekk/paxos/MasterProposerTest.java b/same/src/test/java/com/orbekk/paxos/MasterProposerTest.java
new file mode 100644
index 0000000..74c817f
--- /dev/null
+++ b/same/src/test/java/com/orbekk/paxos/MasterProposerTest.java
@@ -0,0 +1,58 @@
+package com.orbekk.paxos;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import com.orbekk.same.TestConnectionManager;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.Mockito.*;
+
+public class MasterProposerTest {
+    TestConnectionManager connections = new TestConnectionManager();
+    PaxosService p1 = mock(PaxosService.class);
+    PaxosService p2 = mock(PaxosService.class);
+    PaxosService p3 = mock(PaxosService.class);
+    PaxosService p4 = mock(PaxosService.class);
+    PaxosService p5 = mock(PaxosService.class);
+    String master = null;
+    
+    private class TestMasterAction implements Runnable {
+        String tag;
+        TestMasterAction(String tag) {
+            this.tag = tag;
+        }
+        
+        @Override public void run() {
+            master = tag;
+        }
+    }
+    
+    @Before public void setUp() {
+    }
+    
+    List<String> paxosUrls() {
+        List<String> urls = new ArrayList<String>();
+        urls.addAll(connections.paxosMap.keySet());
+        return urls;
+    }
+    
+    @Test public void successfulProposal() {
+        connections.paxosMap.put("p1", p1);
+        when(p1.propose("client1", 1, 1)).thenReturn(true);
+        when(p1.acceptRequest("client1", 1, 1)).thenReturn(true);
+        
+        MasterProposer c1 = new MasterProposer(
+                "client1",
+                paxosUrls(),
+                0,
+                connections,
+                MasterProposer.getTimeoutAction(0),
+                new TestMasterAction("c1"));
+        c1.run();
+        assertEquals("c1", master);
+    }
+}