diff --git a/hyracks/hyracks-algebricks/hyracks-algebricks-common/pom.xml b/hyracks/hyracks-algebricks/hyracks-algebricks-common/pom.xml
new file mode 100644
index 0000000..5996eda
--- /dev/null
+++ b/hyracks/hyracks-algebricks/hyracks-algebricks-common/pom.xml
@@ -0,0 +1,31 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <artifactId>hyracks-algebricks-common</artifactId>
+
+  <parent>
+    <groupId>edu.uci.ics.hyracks</groupId>
+    <artifactId>hyracks-algebricks</artifactId>
+    <version>0.2.1-SNAPSHOT</version>
+  </parent>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>2.0.2</version>
+        <configuration>
+          <source>1.6</source>
+          <target>1.6</target>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+  <dependencies>
+  <dependency>
+  	<groupId>edu.uci.ics.hyracks</groupId>
+  	<artifactId>hyracks-api</artifactId>
+  	<version>0.2.1-SNAPSHOT</version>
+  </dependency>
+  </dependencies>
+</project>
diff --git a/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/constraints/AlgebricksAbsolutePartitionConstraint.java b/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/constraints/AlgebricksAbsolutePartitionConstraint.java
new file mode 100644
index 0000000..924d85b
--- /dev/null
+++ b/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/constraints/AlgebricksAbsolutePartitionConstraint.java
@@ -0,0 +1,32 @@
+/*
+ * Copyright 2009-2010 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.hyracks.algebricks.common.constraints;
+
+public class AlgebricksAbsolutePartitionConstraint extends AlgebricksPartitionConstraint {
+    private final String[] locations;
+
+    public AlgebricksAbsolutePartitionConstraint(String[] locations) {
+        this.locations = locations;
+    }
+
+    @Override
+    public PartitionConstraintType getPartitionConstraintType() {
+        return PartitionConstraintType.ABSOLUTE;
+    }
+
+    public String[] getLocations() {
+        return locations;
+    }
+}
\ No newline at end of file
diff --git a/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/constraints/AlgebricksCountPartitionConstraint.java b/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/constraints/AlgebricksCountPartitionConstraint.java
new file mode 100644
index 0000000..99091aa
--- /dev/null
+++ b/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/constraints/AlgebricksCountPartitionConstraint.java
@@ -0,0 +1,34 @@
+/*
+ * Copyright 2009-2010 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.hyracks.algebricks.common.constraints;
+
+public class AlgebricksCountPartitionConstraint extends AlgebricksPartitionConstraint {
+
+    private final int count;
+
+    public AlgebricksCountPartitionConstraint(int count) {
+        this.count = count;
+    }
+
+    @Override
+    public PartitionConstraintType getPartitionConstraintType() {
+        return PartitionConstraintType.COUNT;
+    }
+
+    public int getCount() {
+        return count;
+    }
+
+}
diff --git a/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/constraints/AlgebricksPartitionConstraint.java b/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/constraints/AlgebricksPartitionConstraint.java
new file mode 100644
index 0000000..929479c
--- /dev/null
+++ b/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/constraints/AlgebricksPartitionConstraint.java
@@ -0,0 +1,24 @@
+/*
+ * Copyright 2009-2010 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.hyracks.algebricks.common.constraints;
+
+public abstract class AlgebricksPartitionConstraint {
+    public enum PartitionConstraintType {
+        ABSOLUTE,
+        COUNT
+    }
+
+    public abstract PartitionConstraintType getPartitionConstraintType();
+}
\ No newline at end of file
diff --git a/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/constraints/AlgebricksPartitionConstraintHelper.java b/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/constraints/AlgebricksPartitionConstraintHelper.java
new file mode 100644
index 0000000..54cdb59
--- /dev/null
+++ b/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/constraints/AlgebricksPartitionConstraintHelper.java
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2009-2010 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.hyracks.algebricks.common.constraints;
+
+import edu.uci.ics.hyracks.api.constraints.PartitionConstraintHelper;
+import edu.uci.ics.hyracks.api.dataflow.IOperatorDescriptor;
+import edu.uci.ics.hyracks.api.job.JobSpecification;
+
+public class AlgebricksPartitionConstraintHelper {
+
+    public static void setPartitionConstraintInJobSpec(JobSpecification jobSpec, IOperatorDescriptor opDesc,
+            AlgebricksPartitionConstraint apc) {
+        switch (apc.getPartitionConstraintType()) {
+            case ABSOLUTE: {
+                AlgebricksAbsolutePartitionConstraint absPc = (AlgebricksAbsolutePartitionConstraint) apc;
+                PartitionConstraintHelper.addAbsoluteLocationConstraint(jobSpec, opDesc, absPc.getLocations());
+                break;
+            }
+            case COUNT: {
+                AlgebricksCountPartitionConstraint cntPc = (AlgebricksCountPartitionConstraint) apc;
+                PartitionConstraintHelper.addPartitionCountConstraint(jobSpec, opDesc, cntPc.getCount());
+                break;
+            }
+            default: {
+                throw new IllegalStateException();
+            }
+        }
+    }
+
+    public static int getPartitionCount(AlgebricksPartitionConstraint partitionConstraint) {
+        switch (partitionConstraint.getPartitionConstraintType()) {
+            case COUNT: {
+                AlgebricksCountPartitionConstraint pcc = (AlgebricksCountPartitionConstraint) partitionConstraint;
+                return pcc.getCount();
+            }
+            case ABSOLUTE: {
+                AlgebricksAbsolutePartitionConstraint epc = (AlgebricksAbsolutePartitionConstraint) partitionConstraint;
+                return epc.getLocations().length;
+            }
+            default: {
+                throw new IllegalStateException();
+            }
+        }
+    }
+
+}
diff --git a/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/exceptions/AlgebricksException.java b/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/exceptions/AlgebricksException.java
new file mode 100644
index 0000000..b55a4b3
--- /dev/null
+++ b/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/exceptions/AlgebricksException.java
@@ -0,0 +1,34 @@
+/*
+ * Copyright 2009-2010 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.hyracks.algebricks.common.exceptions;
+
+public class AlgebricksException extends Exception {
+    private static final long serialVersionUID = 1L;
+
+    public AlgebricksException() {
+    }
+
+    public AlgebricksException(String message) {
+        super(message);
+    }
+
+    public AlgebricksException(Throwable cause) {
+        super(cause);
+    }
+
+    public AlgebricksException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}
\ No newline at end of file
diff --git a/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/exceptions/NotImplementedException.java b/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/exceptions/NotImplementedException.java
new file mode 100644
index 0000000..cb9e054
--- /dev/null
+++ b/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/exceptions/NotImplementedException.java
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2009-2010 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.hyracks.algebricks.common.exceptions;
+
+public class NotImplementedException extends RuntimeException {
+    private static final long serialVersionUID = 2L;
+
+    public NotImplementedException() {
+        System.err.println("Not implemented.");
+    }
+
+    public NotImplementedException(String message) {
+        super(message);
+    }
+
+    public NotImplementedException(Throwable cause) {
+        super(cause);
+    }
+
+    public NotImplementedException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}
\ No newline at end of file
diff --git a/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/utils/ListSet.java b/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/utils/ListSet.java
new file mode 100644
index 0000000..acf1e6f
--- /dev/null
+++ b/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/utils/ListSet.java
@@ -0,0 +1,111 @@
+package edu.uci.ics.hyracks.algebricks.common.utils;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Set;
+
+public class ListSet<E> implements Set<E> {
+    private List<E> list = new ArrayList<E>();
+
+    public ListSet() {
+    }
+
+    public ListSet(Collection<? extends E> arg) {
+        this.addAll(arg);
+    }
+
+    @Override
+    public boolean add(E arg0) {
+        if (list.contains(arg0))
+            return false;
+        return list.add(arg0);
+    }
+
+    @Override
+    public boolean addAll(Collection<? extends E> arg0) {
+        for (E item : arg0)
+            if (list.contains(item))
+                return false;
+        return list.addAll(arg0);
+    }
+
+    @Override
+    public void clear() {
+        list.clear();
+    }
+
+    @Override
+    public boolean contains(Object arg0) {
+        return list.contains(arg0);
+    }
+
+    @Override
+    public boolean containsAll(Collection<?> arg0) {
+        return list.containsAll(arg0);
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return list.isEmpty();
+    }
+
+    @Override
+    public Iterator<E> iterator() {
+        return list.iterator();
+    }
+
+    @Override
+    public boolean remove(Object arg0) {
+        return list.remove(arg0);
+    }
+
+    @Override
+    public boolean removeAll(Collection<?> arg0) {
+        return list.removeAll(arg0);
+    }
+
+    @Override
+    public boolean retainAll(Collection<?> arg0) {
+        return list.retainAll(arg0);
+    }
+
+    @Override
+    public int size() {
+        return list.size();
+    }
+
+    @Override
+    public Object[] toArray() {
+        return list.toArray();
+    }
+
+    @Override
+    public <T> T[] toArray(T[] arg0) {
+        return list.toArray(arg0);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public boolean equals(Object arg) {
+        if (!(arg instanceof Set))
+            return false;
+        Set<E> set = (Set<E>) arg;
+        for (E item : set) {
+            if (!this.contains(item))
+                return false;
+        }
+        for (E item : this) {
+            if (!set.contains(item))
+                return false;
+        }
+        return true;
+    }
+
+    @Override
+    public String toString() {
+        return list.toString();
+    }
+
+}
diff --git a/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/utils/Pair.java b/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/utils/Pair.java
new file mode 100644
index 0000000..ddd56da
--- /dev/null
+++ b/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/utils/Pair.java
@@ -0,0 +1,50 @@
+/*
+ * Copyright 2009-2010 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.hyracks.algebricks.common.utils;
+
+import java.io.Serializable;
+
+public class Pair<T1, T2> implements Serializable {
+
+    private static final long serialVersionUID = 1L;
+    public T1 first;
+    public T2 second;
+
+    public Pair(T1 first, T2 second) {
+        this.first = first;
+        this.second = second;
+    }
+
+    @Override
+    public String toString() {
+        return first + "," + second;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (!(obj instanceof Pair<?, ?>)) {
+            return false;
+        } else {
+            Pair<?, ?> p = (Pair<?, ?>) obj;
+            return this.first.equals(p.first) && this.second.equals(p.second);
+        }
+    }
+
+    @Override
+    public int hashCode() {
+        return first.hashCode() * 31 + second.hashCode();
+    }
+
+}
\ No newline at end of file
diff --git a/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/utils/Triple.java b/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/utils/Triple.java
new file mode 100644
index 0000000..0361152
--- /dev/null
+++ b/hyracks/hyracks-algebricks/hyracks-algebricks-common/src/main/java/edu/uci/ics/hyracks/algebricks/common/utils/Triple.java
@@ -0,0 +1,46 @@
+/*
+ * Copyright 2009-2010 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package edu.uci.ics.hyracks.algebricks.common.utils;
+
+public class Triple<T1, T2, T3> {
+    public T1 first;
+    public T2 second;
+    public T3 third;
+
+    public Triple(T1 first, T2 second, T3 third) {
+        this.first = first;
+        this.second = second;
+        this.third = third;
+    }
+
+    @Override
+    public String toString() {
+        return first + "," + second + ", " + third;
+    }
+
+    @Override
+    public int hashCode() {
+        return first.hashCode() * 31 + second.hashCode() * 15 + third.hashCode();
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (!(o instanceof Triple<?, ?, ?>))
+            return false;
+        Triple<?, ?, ?> triple = (Triple<?, ?, ?>) o;
+        return first.equals(triple.first) && second.equals(triple.second) && third.equals(triple.third);
+    }
+
+}