view flys-artifacts/src/main/java/de/intevation/flys/artifacts/datacage/templating/CompiledStatement.java @ 4282:8b4988815974

Added marker for Ws and Qs in Historical Discharge WQ charts. Therefore, the XYChartGenerator got two new methods addDomainMarker(Marker, boolean) and addValueMarker(Marker, boolean). The boolean parameters determine, if the marker should be visible or not. This is analogous to addAxisSeries(XYSeries, int, boolean).
author Ingo Weinzierl <ingo.weinzierl@intevation.de>
date Mon, 29 Oct 2012 05:59:27 +0100
parents 5642a83420f2
children c1df0dac140b
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package de.intevation.flys.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 de.intevation.flys.artifacts.cache.CacheFactory;

import org.apache.log4j.Logger;

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() {
        }

        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;

        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;
    }
}
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