--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/flys-artifacts/src/main/java/org/dive4elements/river/artifacts/datacage/templating/CompiledStatement.java	Thu Apr 25 12:06:39 2013 +0200
@@ -0,0 +1,216 @@
+package org.dive4elements.river.artifacts.datacage.templating;
+
+import java.util.regex.Pattern;
+import java.util.regex.Matcher;
+
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+import java.util.ArrayList;
+
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+import java.sql.Connection;
+import java.sql.ResultSet;
+
+import net.sf.ehcache.Cache;
+import net.sf.ehcache.Element;
+
+import org.dive4elements.river.artifacts.cache.CacheFactory;
+
+import org.apache.log4j.Logger;
+
+/** SQL Statement, create PreparedStatement. */
+public class CompiledStatement
+{
+    private static Logger log = Logger.getLogger(CompiledStatement.class);
+
+    public static final String DATACAGE_DB_CACHE =
+        "datacage.db";
+
+    public static final Pattern VAR =
+        Pattern.compile("\\$\\{([a-zA-Z0-9_-]+)\\}");
+
+    protected String original;
+    protected String statement;
+
+    protected Map<String, List<Integer>> positions;
+
+    protected int numVars;
+
+    public class Instance {
+
+        protected PreparedStatement preparedStatement;
+
+        public Instance() {
+        }
+
+        /** Executes a Statement. */
+        protected ResultData executeCached(
+            Cache       cache,
+            Connection  connection,
+            StackFrames frames
+        )
+        throws SQLException
+        {
+            log.debug("executeCached");
+            Object [] values = new Object[numVars];
+
+            StringBuilder sb = new StringBuilder(original);
+
+            for (Map.Entry<String, List<Integer>> entry: positions.entrySet()) {
+                String key   = entry.getKey();
+                Object value = frames.get(key);
+                sb.append(';').append(key).append(':').append(value);
+                for (Integer index: entry.getValue()) {
+                    values[index] = value;
+                }
+            }
+
+            // XXX: Maybe too many collisions?
+            // String key = original + Arrays.hashCode(values);
+            String key = sb.toString();
+
+            Element element = cache.get(key);
+
+            if (element != null) {
+                return (ResultData)element.getValue();
+            }
+
+            if (preparedStatement == null) {
+                preparedStatement = connection.prepareStatement(statement);
+            }
+
+            for (int i = 0; i < values.length; ++i) {
+                preparedStatement.setObject(i+1, values[i]);
+            }
+
+            ResultData data;
+
+            if (log.isDebugEnabled()) {
+                log.debug("executing: " + statement);
+            }
+
+            ResultSet result = preparedStatement.executeQuery();
+            try {
+                data = new ResultData(preparedStatement.getMetaData())
+                    .addAll(result);
+            }
+            finally {
+                result.close();
+            }
+
+            element = new Element(key, data);
+            cache.put(element);
+
+            return data;
+        }
+
+        protected ResultData executeUncached(
+            Connection  connection,
+            StackFrames frames
+        )
+        throws SQLException
+        {
+            log.debug("executeUncached");
+            if (preparedStatement == null) {
+                if (log.isDebugEnabled()) {
+                    log.debug("preparing statement: " + statement);
+                }
+                preparedStatement = connection.prepareStatement(statement);
+            }
+
+            for (Map.Entry<String, List<Integer>> entry: positions.entrySet()) {
+                Object value = frames.get(entry.getKey());
+                for (Integer index: entry.getValue()) {
+                    preparedStatement.setObject(index+1, value);
+                }
+            }
+
+            if (log.isDebugEnabled()) {
+                log.debug("executing: " + statement);
+            }
+
+            ResultSet result = preparedStatement.executeQuery();
+            try {
+                return new ResultData(preparedStatement.getMetaData())
+                    .addAll(result);
+            }
+            finally {
+                result.close();
+            }
+        }
+
+        public ResultData execute(
+            Connection  connection,
+            StackFrames frames,
+            boolean     cached
+        )
+        throws SQLException
+        {
+            if (!cached) {
+                return executeUncached(connection, frames);
+            }
+
+            Cache cache = CacheFactory.getCache(DATACAGE_DB_CACHE);
+
+            return cache != null
+                ? executeCached(cache, connection, frames)
+                : executeUncached(connection, frames);
+        }
+
+        public void close() {
+            if (preparedStatement != null) {
+                try {
+                    preparedStatement.close();
+                }
+                catch (SQLException sqle) {
+                }
+                preparedStatement = null;
+            }
+        }
+    } // class Instance
+
+    public CompiledStatement() {
+    }
+
+    public CompiledStatement(String original) {
+        this.original = original;
+        // TreeMap to ensure order
+        positions = new TreeMap<String, List<Integer>>();
+        compile();
+    }
+
+    protected void compile() {
+
+        StringBuffer sb = new StringBuffer();
+
+        Matcher m = VAR.matcher(original);
+
+        int index = 0;
+
+        // Find variables like ${varname}.
+        while (m.find()) {
+            String key = m.group(1).toUpperCase();
+            List<Integer> indices = positions.get(key);
+            if (indices == null) {
+                indices = new ArrayList<Integer>();
+                positions.put(key, indices);
+            }
+            indices.add(index);
+            m.appendReplacement(sb, "?");
+            ++index;
+        }
+
+        m.appendTail(sb);
+
+        numVars = index;
+
+        statement = sb.toString();
+    }
+
+    public String getStatement() {
+        return statement;
+    }
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :