1 files changed, 63 insertions, 0 deletions
diff --git a/third_party/checker_framework_dataflow/java/org/checkerframework/dataflow/cfg/block/BlockImpl.java b/third_party/checker_framework_dataflow/java/org/checkerframework/dataflow/cfg/block/BlockImpl.java
new file mode 100644
index 0000000000..568b62b071
--- /dev/null
+++ b/third_party/checker_framework_dataflow/java/org/checkerframework/dataflow/cfg/block/BlockImpl.java
@@ -0,0 +1,63 @@
+package org.checkerframework.dataflow.cfg.block;
+
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * Base class of the {@link Block} implementation hierarchy.
+ *
+ * @author Stefan Heule
+ *
+ */
+public abstract class BlockImpl implements Block {
+
+    /** A unique ID for this node. */
+    protected long id = BlockImpl.uniqueID();
+
+    /** The last ID that has already been used. */
+    protected static long lastId = 0;
+
+    /** The type of this basic block. */
+    protected BlockType type;
+
+    /** The set of predecessors. */
+    protected Set<BlockImpl> predecessors;
+
+    /**
+     * @return a fresh identifier
+     */
+    private static long uniqueID() {
+        return lastId++;
+    }
+
+    public BlockImpl() {
+        predecessors = new HashSet<>();
+    }
+
+    @Override
+    public long getId() {
+        return id;
+    }
+
+    @Override
+    public BlockType getType() {
+        return type;
+    }
+
+    /**
+     * @return the list of predecessors of this basic block
+     */
+    public Set<BlockImpl> getPredecessors() {
+        return Collections.unmodifiableSet(predecessors);
+    }
+
+    public void addPredecessor(BlockImpl pred) {
+        predecessors.add(pred);
+    }
+
+    public void removePredecessor(BlockImpl pred) {
+        predecessors.remove(pred);
+    }
+
+}