diff --git a/framework/src/main/java/org/apache/felix/framework/capabilityset/SimpleFilter.java b/framework/src/main/java/org/apache/felix/framework/capabilityset/SimpleFilter.java
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+++ b/framework/src/main/java/org/apache/felix/framework/capabilityset/SimpleFilter.java
@@ -0,0 +1,388 @@
+/*
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you 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 at
+ * 
+ *    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 org.apache.felix.framework.capabilityset;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class SimpleFilter
+{
+    public static final int AND = 1;
+    public static final int OR = 2;
+    public static final int NOT = 3;
+    public static final int EQ = 4;
+    public static final int LTE = 5;
+    public static final int GTE = 6;
+// TODO: FELIX3 - Should we handle substring as a separate operator or as a
+//       special case of string equality comparison?
+    public static final int SUBSTRING = 7;
+
+    private final String m_name;
+    private final Object m_value;
+    private final int m_op;
+
+    public SimpleFilter(String attr, Object value, int op)
+    {
+        m_name = attr;
+        m_value = value;
+        m_op = op;
+    }
+
+    public String getName()
+    {
+        return m_name;
+    }
+
+    public Object getValue()
+    {
+        return m_value;
+    }
+
+    public int getOperation()
+    {
+        return m_op;
+    }
+
+    public String toString()
+    {
+        String s = null;
+        switch (m_op)
+        {
+            case AND:
+                s = "(&" + toString((List) m_value) + ")";
+                break;
+            case OR:
+                s = "(|" + toString((List) m_value) + ")";
+                break;
+            case NOT:
+                s = "(!" + toString((List) m_value) + ")";
+                break;
+            case EQ:
+                s = "(" + m_name + "=" + m_value + ")";
+                break;
+            case LTE:
+                s = "(" + m_name + "<=" + m_value + ")";
+                break;
+            case GTE:
+                s = "(" + m_name + ">=" + m_value + ")";
+                break;
+            case SUBSTRING:
+                s = "(" + m_name + "=" + unparseSubstring((List<String>) m_value) + ")";
+                break;
+        }
+        return s;
+    }
+
+    private String toString(List list)
+    {
+        StringBuffer sb = new StringBuffer();
+        for (int i = 0; i < list.size(); i++)
+        {
+            sb.append(list.get(i).toString());
+        }
+        return sb.toString();
+    }
+
+    public static SimpleFilter parse(String filter)
+    {
+        filter = filter.trim();
+
+        if ((filter == null) || (filter.length() == 0))
+        {
+            throw new IllegalArgumentException("Null or empty filter.");
+        }
+        else if (filter.charAt(0) != '(')
+        {
+            throw new IllegalArgumentException("Missing opening parenthesis: " + filter);
+        }
+
+        SimpleFilter sf = null;
+        List stack = new ArrayList();
+        for (int i = 0; i < filter.length(); i++)
+        {
+            if (sf != null)
+            {
+                throw new IllegalArgumentException(
+                    "Only one top-level operation allowed: " + filter);
+            }
+            if (filter.charAt(i) == '(')
+            {
+                if (filter.charAt(i+1) == '&')
+                {
+                    stack.add(0, new SimpleFilter(null, new ArrayList(), SimpleFilter.AND));
+                }
+                else if (filter.charAt(i+1) == '|')
+                {
+                    stack.add(0, new SimpleFilter(null, new ArrayList(), SimpleFilter.OR));
+                }
+                else if (filter.charAt(i+1) == '!')
+                {
+                    stack.add(0, new SimpleFilter(null, new ArrayList(), SimpleFilter.NOT));
+                }
+                else
+                {
+                    stack.add(0, new Integer(i));
+                }
+            }
+            else if (filter.charAt(i) == ')')
+            {
+                Object top = stack.remove(0);
+                if (top instanceof SimpleFilter)
+                {
+                    if (!stack.isEmpty() && (stack.get(0) instanceof SimpleFilter))
+                    {
+                        ((List) ((SimpleFilter) stack.get(0)).m_value).add(top);
+                    }
+                    else
+                    {
+                        sf = (SimpleFilter) top;
+                    }
+                }
+                else if (!stack.isEmpty() && (stack.get(0) instanceof SimpleFilter))
+                {
+                    ((List) ((SimpleFilter) stack.get(0)).m_value).add(
+                        SimpleFilter.subfilter(filter, ((Integer) top).intValue() + 1, i));
+                }
+                else
+                {
+                    sf = SimpleFilter.subfilter(filter, ((Integer) top).intValue() + 1, i);
+                }
+            }
+        }
+
+        if (sf == null)
+        {
+            throw new IllegalArgumentException("Missing closing parenthesis: " + filter);
+        }
+
+        return sf;
+    }
+
+    private static SimpleFilter subfilter(String filter, int startIdx, int endIdx)
+    {
+        final String opChars = "=<>";
+        String attr = null;
+        Object value = null;
+        int op = -1;
+        for (int i = 0; i < (endIdx - startIdx); i++)
+        {
+            if (opChars.indexOf(filter.charAt(startIdx + i)) >= 0)
+            {
+                switch (filter.charAt(startIdx + i))
+                {
+                    case '=':
+                        attr = filter.substring(startIdx, startIdx + i);
+                        List<String> values =
+                            parseSubstring(filter.substring(startIdx + i + 1, endIdx));
+                        if (values.size() > 1)
+                        {
+                            op = SUBSTRING;
+                            value = values;
+                        }
+                        else
+                        {
+                            op = EQ;
+                            value = values.get(0);
+                        }
+                        break;
+                    case '<':
+                        if (filter.charAt(startIdx + i + 1) != '=')
+                        {
+                            throw new IllegalArgumentException(
+                                "Unknown operator: " + filter.substring(startIdx, endIdx));
+                        }
+                        attr = filter.substring(startIdx, startIdx + i);
+                        op = LTE;
+                        value = filter.substring(startIdx + i + 2, endIdx);
+                        break;
+                    case '>':
+                        if (filter.charAt(startIdx + i + 1) != '=')
+                        {
+                            throw new IllegalArgumentException(
+                                "Unknown operator: " + filter.substring(startIdx, endIdx));
+                        }
+                        attr = filter.substring(startIdx, startIdx + i);
+                        op = GTE;
+                        value = filter.substring(startIdx + i + 2, endIdx);
+                        break;
+                    default:
+                        throw new IllegalArgumentException(
+                            "Unknown operator: " + filter.substring(startIdx, endIdx));
+                }
+                break;
+            }
+        }
+
+        return new SimpleFilter(attr, value, op);
+    }
+
+// TODO: FELIX3 - Merge with Util class.
+    public static List<String> parseSubstring(String value)
+    {
+        List<String> pieces = new ArrayList();
+        StringBuffer ss = new StringBuffer();
+        // int kind = SIMPLE; // assume until proven otherwise
+        boolean wasStar = false; // indicates last piece was a star
+        boolean leftstar = false; // track if the initial piece is a star
+        boolean rightstar = false; // track if the final piece is a star
+
+        int idx = 0;
+
+        // We assume (sub)strings can contain leading and trailing blanks
+loop:   for (;;)
+        {
+            if (idx >= value.length())
+            {
+                if (wasStar)
+                {
+                    // insert last piece as "" to handle trailing star
+                    rightstar = true;
+                }
+                else
+                {
+                    pieces.add(ss.toString());
+                    // accumulate the last piece
+                    // note that in the case of
+                    // (cn=); this might be
+                    // the string "" (!=null)
+                }
+                ss.setLength(0);
+                break loop;
+            }
+
+            char c = value.charAt(idx++);
+            if (c == '*')
+            {
+                if (wasStar)
+                {
+                    // encountered two successive stars;
+                    // I assume this is illegal
+                    throw new IllegalArgumentException("Invalid filter string: " + value);
+                }
+                if (ss.length() > 0)
+                {
+                    pieces.add(ss.toString()); // accumulate the pieces
+                    // between '*' occurrences
+                }
+                ss.setLength(0);
+                // if this is a leading star, then track it
+                if (pieces.size() == 0)
+                {
+                    leftstar = true;
+                }
+                wasStar = true;
+            }
+            else
+            {
+                wasStar = false;
+                ss.append(c);
+            }
+        }
+        if (leftstar || rightstar || pieces.size() > 1)
+        {
+            // insert leading and/or trailing "" to anchor ends
+            if (rightstar)
+            {
+                pieces.add("");
+            }
+            if (leftstar)
+            {
+                pieces.add(0, "");
+            }
+        }
+        return pieces;
+    }
+
+    public static String unparseSubstring(List<String> pieces)
+    {
+        StringBuffer sb = new StringBuffer();
+        for (int i = 0; i < pieces.size(); i++)
+        {
+            if (i > 0)
+            {
+                sb.append("*");
+            }
+            sb.append(pieces.get(i));
+        }
+        return sb.toString();
+    }
+
+// TODO: FELIX3 - Merge with Util class.
+    public static boolean compareSubstring(String s, List<String> pieces)
+    {
+        // Walk the pieces to match the string
+        // There are implicit stars between each piece,
+        // and the first and last pieces might be "" to anchor the match.
+        // assert (pieces.length > 1)
+        // minimal case is <string>*<string>
+
+        boolean result = true;
+        int len = pieces.size();
+
+        int index = 0;
+
+loop:   for (int i = 0; i < len; i++)
+        {
+            String piece = pieces.get(i);
+
+            // If this is the first piece, then make sure the
+            // string starts with it.
+            if (i == 0)
+            {
+                if (!s.startsWith(piece))
+                {
+                    result = false;
+                    break loop;
+                }
+            }
+
+            // If this is the last piece, then make sure the
+            // string ends with it.
+            if (i == len - 1)
+            {
+                if (s.endsWith(piece))
+                {
+                    result = true;
+                }
+                else
+                {
+                    result = false;
+                }
+                break loop;
+            }
+
+            // If this is neither the first or last piece, then
+            // make sure the string contains it.
+            if ((i > 0) && (i < (len - 1)))
+            {
+                index = s.indexOf(piece, index);
+                if (index < 0)
+                {
+                    result = false;
+                    break loop;
+                }
+            }
+
+            // Move string index beyond the matching piece.
+            index += piece.length();
+        }
+
+        return result;
+    }
+}
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