sascha@372: package de.intevation.flys.artifacts.services.meta;
sascha@372: 
sascha@372: import java.util.regex.Pattern;
sascha@372: import java.util.regex.Matcher;
sascha@372: 
sascha@372: import java.util.List;
sascha@372: import java.util.Map;
sascha@972: import java.util.TreeMap;
sascha@372: import java.util.ArrayList;
sascha@372: 
sascha@372: import java.sql.PreparedStatement;
sascha@372: import java.sql.SQLException;
sascha@372: import java.sql.Connection;
sascha@372: import java.sql.ResultSet;
sascha@372: 
sascha@972: import net.sf.ehcache.Cache;
sascha@972: import net.sf.ehcache.Element;
sascha@972: 
sascha@972: import de.intevation.flys.artifacts.cache.CacheFactory;
sascha@972: 
sascha@372: public class CompiledStatement
sascha@372: {
sascha@972:     public static final String DATACAGE_DB_CACHE =
sascha@972:         "datacage.db";
sascha@972: 
sascha@969:     public static final Pattern VAR =
sascha@969:         Pattern.compile("\\$\\{([a-zA-Z0-9_-]+)\\}");
sascha@372: 
sascha@372:     protected String original;
sascha@372:     protected String statement;
sascha@372: 
sascha@372:     protected Map<String, List<Integer>> positions;
sascha@372: 
sascha@372:     protected PreparedStatement preparedStatement;
sascha@372: 
sascha@972:     protected int numVars;
sascha@972: 
sascha@372:     public CompiledStatement() {
sascha@372:     }
sascha@372: 
sascha@372:     public CompiledStatement(String original) {
sascha@372:         this.original = original;
sascha@972:         // TreeMap to ensure order
sascha@972:         positions = new TreeMap<String, List<Integer>>();
sascha@372:         compile();
sascha@372:     }
sascha@372: 
sascha@372:     protected void compile() {
sascha@372: 
sascha@372:         StringBuffer sb = new StringBuffer();
sascha@372: 
sascha@372:         Matcher m = VAR.matcher(original);
sascha@372: 
sascha@972:         int index = 0;
sascha@372: 
sascha@372:         while (m.find()) {
sascha@372:             String key = m.group(1);
sascha@372:             List<Integer> indices = positions.get(key);
sascha@372:             if (indices == null) {
sascha@372:                 indices = new ArrayList<Integer>();
sascha@372:                 positions.put(key, indices);
sascha@372:             }
sascha@372:             indices.add(index);
sascha@372:             m.appendReplacement(sb, "?");
sascha@372:             ++index;
sascha@372:         }
sascha@372: 
sascha@372:         m.appendTail(sb);
sascha@372: 
sascha@972:         numVars = index;
sascha@972: 
sascha@372:         statement = sb.toString();
sascha@372:     }
sascha@372: 
sascha@372:     public String getStatement() {
sascha@372:         return statement;
sascha@372:     }
sascha@372: 
sascha@972:     protected ResultData executeCached(
sascha@972:         Cache       cache,
sascha@972:         Connection  connection,
sascha@972:         StackFrames frames
sascha@972:     )
sascha@972:     throws SQLException
sascha@972:     {
sascha@972:         Object [] values = new Object[numVars];
sascha@972: 
sascha@972:         StringBuilder sb = new StringBuilder(original);
sascha@972: 
sascha@972:         for (Map.Entry<String, List<Integer>> entry: positions.entrySet()) {
sascha@972:             String key   = entry.getKey();
sascha@972:             Object value = frames.get(key);
sascha@972:             sb.append(';').append(key).append(':').append(value);
sascha@972:             for (Integer index: entry.getValue()) {
sascha@972:                 values[index] = value;
sascha@972:             }
sascha@972:         }
sascha@972: 
sascha@972:         // XXX: Maybe too many collisions?
sascha@972:         // String key = original + Arrays.hashCode(values);
sascha@972:         String key = sb.toString();
sascha@972: 
sascha@972:         Element element = cache.get(key);
sascha@972: 
sascha@972:         if (element != null) {
sascha@972:             return (ResultData)element.getValue();
sascha@972:         }
sascha@972: 
sascha@972:         if (preparedStatement == null) {
sascha@972:             preparedStatement = connection.prepareStatement(statement);
sascha@972:         }
sascha@972: 
sascha@972:         for (int i = 0; i < values.length; ++i) {
sascha@972:             preparedStatement.setObject(i+1, values[i]);
sascha@972:         }
sascha@972: 
sascha@972:         ResultData data;
sascha@972: 
sascha@972:         ResultSet result = preparedStatement.executeQuery();
sascha@972:         try {
sascha@972:             data = new ResultData(preparedStatement.getMetaData())
sascha@972:                 .addAll(result);
sascha@972:         }
sascha@972:         finally {
sascha@972:             result.close();
sascha@972:         }
sascha@972: 
sascha@972:         element = new Element(key, data);
sascha@972:         cache.put(element);
sascha@972: 
sascha@972:         return data;
sascha@972:     }
sascha@972: 
sascha@972:     protected ResultData executeUncached(
sascha@972:         Connection  connection,
sascha@972:         StackFrames frames
sascha@972:     ) 
sascha@372:     throws SQLException
sascha@372:     {
sascha@372:         if (preparedStatement == null) {
sascha@372:             preparedStatement = connection.prepareStatement(statement);
sascha@372:         }
sascha@372: 
sascha@372:         for (Map.Entry<String, List<Integer>> entry: positions.entrySet()) {
sascha@372:             Object value = frames.get(entry.getKey());
sascha@372:             for (Integer index: entry.getValue()) {
sascha@972:                 preparedStatement.setObject(index+1, value);
sascha@372:             }
sascha@372:         }
sascha@372: 
sascha@372:         ResultSet result = preparedStatement.executeQuery();
sascha@372:         try {
sascha@372:             return new ResultData(preparedStatement.getMetaData())
sascha@372:                 .addAll(result);
sascha@372:         }
sascha@372:         finally {
sascha@372:             result.close();
sascha@372:         }
sascha@372:     }
sascha@372: 
sascha@972:     public ResultData execute(Connection connection, StackFrames frames)
sascha@972:     throws SQLException
sascha@972:     {
sascha@972:         Cache cache = CacheFactory.getCache(DATACAGE_DB_CACHE);
sascha@972: 
sascha@972:         return cache != null
sascha@972:             ? executeCached(cache, connection, frames)
sascha@972:             : executeUncached(connection, frames);
sascha@972:     }
sascha@972: 
sascha@372:     public void close() {
sascha@372:         if (preparedStatement != null) {
sascha@372:             try {
sascha@372:                 preparedStatement.close();
sascha@372:             }
sascha@372:             catch (SQLException sqle) {
sascha@372:             }
sascha@372:             preparedStatement = null;
sascha@372:         }
sascha@372:     }
sascha@372: }
sascha@372: // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :