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comparison flys-artifacts/src/main/java/de/intevation/flys/artifacts/datacage/templating/CompiledStatement.java @ 998:b81626b10cb7

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Datacage: Moved templating in a better suited package. flys-artifacts/trunk@2434 c6561f87-3c4e-4783-a992-168aeb5c3f6f
author Sascha L. Teichmann <sascha.teichmann@intevation.de>
date Mon, 01 Aug 2011 08:31:09 +0000
parents
children aca3b46160cb
comparison
equal deleted inserted replaced
997:4c82609824c8 998:b81626b10cb7
1 package de.intevation.flys.artifacts.datacage.templating;
2
3 import java.util.regex.Pattern;
4 import java.util.regex.Matcher;
5
6 import java.util.List;
7 import java.util.Map;
8 import java.util.TreeMap;
9 import java.util.ArrayList;
10
11 import java.sql.PreparedStatement;
12 import java.sql.SQLException;
13 import java.sql.Connection;
14 import java.sql.ResultSet;
15
16 import net.sf.ehcache.Cache;
17 import net.sf.ehcache.Element;
18
19 import de.intevation.flys.artifacts.cache.CacheFactory;
20
21 public class CompiledStatement
22 {
23 public static final String DATACAGE_DB_CACHE =
24 "datacage.db";
25
26 public static final Pattern VAR =
27 Pattern.compile("\\$\\{([a-zA-Z0-9_-]+)\\}");
28
29 protected String original;
30 protected String statement;
31
32 protected Map<String, List<Integer>> positions;
33
34 protected int numVars;
35
36 public class Instance {
37
38 protected PreparedStatement preparedStatement;
39
40 public Instance() {
41 }
42
43 protected ResultData executeCached(
44 Cache cache,
45 Connection connection,
46 StackFrames frames
47 )
48 throws SQLException
49 {
50 Object [] values = new Object[numVars];
51
52 StringBuilder sb = new StringBuilder(original);
53
54 for (Map.Entry<String, List<Integer>> entry: positions.entrySet()) {
55 String key = entry.getKey();
56 Object value = frames.get(key);
57 sb.append(';').append(key).append(':').append(value);
58 for (Integer index: entry.getValue()) {
59 values[index] = value;
60 }
61 }
62
63 // XXX: Maybe too many collisions?
64 // String key = original + Arrays.hashCode(values);
65 String key = sb.toString();
66
67 Element element = cache.get(key);
68
69 if (element != null) {
70 return (ResultData)element.getValue();
71 }
72
73 if (preparedStatement == null) {
74 preparedStatement = connection.prepareStatement(statement);
75 }
76
77 for (int i = 0; i < values.length; ++i) {
78 preparedStatement.setObject(i+1, values[i]);
79 }
80
81 ResultData data;
82
83 ResultSet result = preparedStatement.executeQuery();
84 try {
85 data = new ResultData(preparedStatement.getMetaData())
86 .addAll(result);
87 }
88 finally {
89 result.close();
90 }
91
92 element = new Element(key, data);
93 cache.put(element);
94
95 return data;
96 }
97
98 protected ResultData executeUncached(
99 Connection connection,
100 StackFrames frames
101 )
102 throws SQLException
103 {
104 if (preparedStatement == null) {
105 preparedStatement = connection.prepareStatement(statement);
106 }
107
108 for (Map.Entry<String, List<Integer>> entry: positions.entrySet()) {
109 Object value = frames.get(entry.getKey());
110 for (Integer index: entry.getValue()) {
111 preparedStatement.setObject(index+1, value);
112 }
113 }
114
115 ResultSet result = preparedStatement.executeQuery();
116 try {
117 return new ResultData(preparedStatement.getMetaData())
118 .addAll(result);
119 }
120 finally {
121 result.close();
122 }
123 }
124
125 public ResultData execute(Connection connection, StackFrames frames)
126 throws SQLException
127 {
128 Cache cache = CacheFactory.getCache(DATACAGE_DB_CACHE);
129
130 return cache != null
131 ? executeCached(cache, connection, frames)
132 : executeUncached(connection, frames);
133 }
134
135 public void close() {
136 if (preparedStatement != null) {
137 try {
138 preparedStatement.close();
139 }
140 catch (SQLException sqle) {
141 }
142 preparedStatement = null;
143 }
144 }
145 } // class Instance
146
147 public CompiledStatement() {
148 }
149
150 public CompiledStatement(String original) {
151 this.original = original;
152 // TreeMap to ensure order
153 positions = new TreeMap<String, List<Integer>>();
154 compile();
155 }
156
157 protected void compile() {
158
159 StringBuffer sb = new StringBuffer();
160
161 Matcher m = VAR.matcher(original);
162
163 int index = 0;
164
165 while (m.find()) {
166 String key = m.group(1);
167 List<Integer> indices = positions.get(key);
168 if (indices == null) {
169 indices = new ArrayList<Integer>();
170 positions.put(key, indices);
171 }
172 indices.add(index);
173 m.appendReplacement(sb, "?");
174 ++index;
175 }
176
177 m.appendTail(sb);
178
179 numVars = index;
180
181 statement = sb.toString();
182 }
183
184 public String getStatement() {
185 return statement;
186 }
187 }
188 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :
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