|
1
55 package org.lateralnz.common.util;
56
57 import java.io.File  ;
58 import java.io.FileWriter ;
59 import java.io.FileInputStream ;
60 import java.io.InputStreamReader ;
61 import java.lang.reflect.Field ;
62 import java.sql.ResultSet ;
63 import java.sql.ResultSetMetaData ;
64 import java.sql.Types ;
65 import java.util.ArrayList ;
66 import java.util.Date ;
67 import java.util.HashMap ;
68 import java.util.List ;
69
70
76 public class ResultSetConverter implements Constants {
77 private static final Class [] DATE_CLASS_TYPE = { Date .class };
78 private static final Class [] DOUBLE_CLASS_TYPE = { Double .class };
79 private static final Class [] LONG_CLASS_TYPE = { Long .class };
80 private static final Class [] STRING_CLASS_TYPE = { String .class };
81
82 private static HashMap instances = new HashMap ();
83
84 private HashMap classes = new HashMap ();
85 private String compilerExecutable;
86
87 private static ResultSetConverter instance = null;
89
90 private ResultSetConverter(String compilerExecutable) {
91 setCompilerExecutable(compilerExecutable);
92 }
93
94 private void setCompilerExecutable(String compilerExecutable) {
95 this.compilerExecutable = compilerExecutable;
96 }
97
98 public static ResultSetConverter getInstance() throws Exception {
99 return getInstance("javac");
100 }
101
102
105 public static ResultSetConverter getInstance(String compilerExecutable) throws Exception {
106 if (!instances.containsKey(compilerExecutable)) {
107 synchronized (instances) {
108 if (!instances.containsKey(compilerExecutable)) {
109 ResultSetConverter rsc = new ResultSetConverter(compilerExecutable);
110 instances.put(compilerExecutable, rsc);
111 }
112 }
113 }
114
115 return (ResultSetConverter)instances.get(compilerExecutable);
116 }
117
118 private final MetaClass getClassForResultSet(String resultName, ResultSet rs) throws Exception {
119 ResultSetMetaData md = rs.getMetaData();
120
121 int count = md.getColumnCount();
122
123 MetaClass metaclass = new MetaClass(count);
124
125 String [] getmethods = new String [count];
126 String [] getomethods = new String [count];
127 String [] setmethods = new String [count];
128 String [] vars = new String [count];
129
130 StringBuffer staticColnames = new StringBuffer ("public static String[] colnames = new String[]{ ");
131
132 for (int i = 0, j = 1; i < count; i++, j++) {
133 int type = md.getColumnType(j);
134 String colname = md.getColumnName(j);
135 staticColnames.append(QUOTE).append(colname).append(QUOTE);
136 if (i < count-1) {
137 staticColnames.append(COMMA);
138 }
139 if (colname.indexOf(SPACE) >= 0) {
140 colname = StringUtils.replace(colname, SPACE, UNDERSCORE);
141 }
142 colname = colname.substring(0,1).toUpperCase() + colname.substring(1);
143 switch (type) {
144 case Types.DECIMAL:
145 case Types.FLOAT:
146 case Types.DOUBLE:
147 metaclass.types[i] = MetaClass.DOUBLE;
148 vars[i] = "public double col" + j + ";";
149 getmethods[i] = "public double get" + colname + "() { return this.col" + j + "; }";
150 getomethods[i] = " new Double(col" + j +")";
151 setmethods[i] = "public void set" + colname + "(double d) { this.col" + j + " = d; }";
152 break;
153 case Types.INTEGER:
154 case Types.SMALLINT:
155 case Types.TINYINT:
156 metaclass.types[i] = MetaClass.LONG;
157 vars[i] = "public long col" + j + ";";
158 getmethods[i] = "public long get" + colname + "() { return this.col" + j + "; }";
159 getomethods[i] = " new Long(col" + j +")";
160 setmethods[i] = "public void set" + colname + "(long l) { this.col" + j + " = l; }";
161 break;
162 case Types.DATE:
163 case Types.TIME:
164 case Types.TIMESTAMP:
165 metaclass.types[i] = MetaClass.DATE;
166 vars[i] = "public Date col" + j + " = null;";
167 getmethods[i] = "public Date get" + colname + "() { return this.col" + j + "; }";
168 getomethods[i] = " col" + j;
169 setmethods[i] = "public void set" + colname + "(Date d) { this.col" + j + " = d; }";
170 break;
171 case Types.VARCHAR:
172 case Types.CHAR:
173 default:
174 metaclass.types[i] = MetaClass.STRING;
175 vars[i] = "public String col" + j + " = null;";
176 getmethods[i] = "public String get" + colname + "() { return this.col" + j + "; }";
177 getomethods[i] = " col" + j;
178 setmethods[i] = "public void set" + colname + "(String s) { this.col" + j + " = s; }";
179 break;
180 }
181 }
182
183 staticColnames.append("};\n\n");
184 staticColnames.append("public static String getColName(int idx) { return colnames[idx]; }\n\n");
185 staticColnames.append("public static int getColCount() { return colnames.length; }\n\n");
186
187 StringBuffer sb = new StringBuffer ("import java.util.Date;\nimport java.util.Iterator;\nimport java.io.Serializable;\n\n");
188 sb.append("public class ResultSetValue_" + resultName + " implements Iterator, Serializable {\n");
189 sb.append(staticColnames.toString()).append(NEWLINE).append(NEWLINE);
190 sb.append("int pos = 0;\nint max = ").append(count).append(";\n\n");
191
192 for (int i = 0; i < count; i++) {
193 sb.append(vars[i]).append(NEWLINE);
194 }
195 for (int i = 0; i < count; i++) {
196 sb.append(getmethods[i]).append(NEWLINE);
197 sb.append(setmethods[i]).append(NEWLINE);
198 }
199 sb.append("public boolean hasNext() { return (pos < max); }\n\n");
200 sb.append("public Object next() {\ntry {\nswitch (pos) {\n");
201 for (int i = 0; i < count; i++) {
202 sb.append("case ").append(i).append(": return ").append(getomethods[i]).append(";\n");
203 }
204 sb.append("default: return null;\n}\n} finally { pos++; }\n}\npublic void remove() { }\n");
205
206 if (count > 0) {
207 sb.append("\npublic String toString() {\nreturn \"\" + ");
208 for (int i = 1; i <= count; i++) {
209 sb.append("col").append(i);
210 if (i < count) {
211 sb.append(" + \",\" + ");
212 }
213 }
214 sb.append(";\n}\n");
215 }
216
217 sb.append(NEWLINE).append("}");
218
219 FileWriter fw = new FileWriter ("ResultSetValue_" + resultName + ".java");
220 fw.write(sb.toString());
221
222 fw.close();
223
224 Process p = Runtime.getRuntime().exec(compilerExecutable + " ResultSetValue_" + resultName + ".java");
225 p.waitFor();
226 if (p.exitValue() != 0) {
227 InputStreamReader isr = null;
228 try {
229 isr = new InputStreamReader (p.getErrorStream());
230 throw new Exception ("error compiling " + StringUtils.readFrom(isr));
231 }
232 finally {
233 IOUtils.close(isr);
234 }
235 }
236
237 File f = new File ("ResultSetValue_" + resultName + ".class");
238 FileInputStream fis = null;
239 byte[] b;
240 try {
241 fis = new FileInputStream (f);
242 b = new byte[(int)f.length()];
243 fis.read(b);
244 }
245 finally {
246 IOUtils.close(fis);
247 }
248
249 InternalClassLoader icl = new InternalClassLoader();
250 Class c = icl.getClass("ResultSetValue_" + resultName, b);
251 metaclass.c = c;
252 classes.put(resultName, metaclass);
253
254 return metaclass;
255 }
256
257 private final Field [] getFields(MetaClass mc) throws Exception {
258 Field [] f = new Field [mc.numOfFields];
259 for (int i = 0, j = 1; i < f.length; i++, j++) {
260 f[i] = mc.c.getField("col" + j);
261 }
262 return f;
263 }
264
265
272 public List getResultSetAsList(String resultSetName, ResultSet rs, boolean forceClassReload) throws Exception {
273 MetaClass metaclass;
274 if (!classes.containsKey(resultSetName) || forceClassReload) {
275 metaclass = getClassForResultSet(resultSetName, rs);
276 }
277 else {
278 metaclass = (MetaClass)classes.get(resultSetName);
279 }
280
281 Field [] fields = getFields(metaclass);
282 Object [] val = new Object [1];
283 ArrayList al = new ArrayList ();
284 while (rs.next()) {
285 Object valobj = metaclass.c.newInstance();
286
287 for (int i = 0, j = 1; i < fields.length; i++, j++) {
288 switch (metaclass.types[i]) {
289 case MetaClass.DATE :
290 fields[i].set(valobj, rs.getTimestamp(j));
291 break;
292 case MetaClass.DOUBLE :
293 fields[i].setDouble(valobj, rs.getDouble(j));
294 break;
295 case MetaClass.LONG :
296 fields[i].setLong(valobj, rs.getLong(j));
297 break;
298 default :
299 fields[i].set(valobj, rs.getString(j));
300 break;
301 }
302 }
303 al.add(valobj);
304 }
305
306 return al;
307 }
308
309 public void reset(String name) {
310 classes.remove(name);
311 }
312
313
316 class InternalClassLoader extends ClassLoader {
317 public InternalClassLoader() {
318 super();
319 }
320
321 public Class getClass(String name, byte[] b) {
322 return super.defineClass(name, b, 0, b.length);
323 }
324 }
325
326 class MetaClass {
327 public static final int STRING = 0;
328 public static final int LONG = 1;
329 public static final int DOUBLE = 2;
330 public static final int DATE = 3;
331
332 int numOfFields;
333 int[] types;
334 Class c;
335
336 public MetaClass(int numOfFields) {
337 this.numOfFields = numOfFields;
338 types = new int[numOfFields];
339 }
340 }
341 } |
Popular Tags |
Java API By Example, From Geeks To Geeks.