Author: wumpz

src/test/java/net/sf/jsqlparser/statement/select/NestedBracketsPerformanceTest.java

@@ -10,7 +10,9 @@
 package net.sf.jsqlparser.statement.select;
 
 import net.sf.jsqlparser.JSQLParserException;
-import net.sf.jsqlparser.test.TestUtils;
+import static net.sf.jsqlparser.test.TestUtils.assertSqlCanBeParsedAndDeparsed;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
 import org.junit.Ignore;
 import org.junit.Test;
 
@@ -22,22 +24,62 @@ public class NestedBracketsPerformanceTest {
 
     @Test
     public void testIssue766() throws JSQLParserException {
-        TestUtils.assertSqlCanBeParsedAndDeparsed("SELECT concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat('1','2'),'3'),'4'),'5'),'6'),'7'),'8'),'9'),'10'),'11'),'12'),'13'),'14'),'15'),'16'),'17'),'18'),'19'),'20'),'21'),col1 FROM tbl t1", true);
+        assertSqlCanBeParsedAndDeparsed("SELECT concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat(concat('1','2'),'3'),'4'),'5'),'6'),'7'),'8'),'9'),'10'),'11'),'12'),'13'),'14'),'15'),'16'),'17'),'18'),'19'),'20'),'21'),col1 FROM tbl t1", true);
     }
 
     @Test
     public void testIssue766_2() throws JSQLParserException {
-        TestUtils.assertSqlCanBeParsedAndDeparsed("SELECT concat(concat(concat('1', '2'), '3'), '4'), col1 FROM tbl t1");
+        assertSqlCanBeParsedAndDeparsed("SELECT concat(concat(concat('1', '2'), '3'), '4'), col1 FROM tbl t1");
     }
 
     @Test
     public void testIssue235() throws JSQLParserException {
-        TestUtils.assertSqlCanBeParsedAndDeparsed("SELECT CASE WHEN ( CASE WHEN ( CASE WHEN ( CASE WHEN ( 1 ) THEN 0 END ) THEN 0 END ) THEN 0 END ) THEN 0 END FROM a", true);
+        assertSqlCanBeParsedAndDeparsed("SELECT CASE WHEN ( CASE WHEN ( CASE WHEN ( CASE WHEN ( 1 ) THEN 0 END ) THEN 0 END ) THEN 0 END ) THEN 0 END FROM a", true);
     }
 
     @Test(timeout = 100000)
     @Ignore
     public void testIssue496() throws JSQLParserException {
-        TestUtils.assertSqlCanBeParsedAndDeparsed("select isNull(charLen(TEST_ID,0)+ isNull(charLen(TEST_DVC,0)+ isNull(charLen(TEST_NO,0)+ isNull(charLen(ATEST_ID,0)+ isNull(charLen(TESTNO,0)+ isNull(charLen(TEST_CTNT,0)+ isNull(charLen(TEST_MESG_CTNT,0)+ isNull(charLen(TEST_DTM,0)+ isNull(charLen(TEST_DTT,0)+ isNull(charLen(TEST_ADTT,0)+ isNull(charLen(TEST_TCD,0)+ isNull(charLen(TEST_PD,0)+ isNull(charLen(TEST_VAL,0)+ isNull(charLen(TEST_YN,0)+ isNull(charLen(TEST_DTACM,0)+ isNull(charLen(TEST_MST,0) from test_info_m");
+        assertSqlCanBeParsedAndDeparsed("select isNull(charLen(TEST_ID,0)+ isNull(charLen(TEST_DVC,0)+ isNull(charLen(TEST_NO,0)+ isNull(charLen(ATEST_ID,0)+ isNull(charLen(TESTNO,0)+ isNull(charLen(TEST_CTNT,0)+ isNull(charLen(TEST_MESG_CTNT,0)+ isNull(charLen(TEST_DTM,0)+ isNull(charLen(TEST_DTT,0)+ isNull(charLen(TEST_ADTT,0)+ isNull(charLen(TEST_TCD,0)+ isNull(charLen(TEST_PD,0)+ isNull(charLen(TEST_VAL,0)+ isNull(charLen(TEST_YN,0)+ isNull(charLen(TEST_DTACM,0)+ isNull(charLen(TEST_MST,0) from test_info_m");
+    }
+
+    /**
+     * Try to avoid or border exceptionally big parsing time increments by adding more bracket constructs.
+     *
+     * @throws JSQLParserException
+     */
+    @Test
+    public void testIncreaseOfParseTime() throws JSQLParserException {
+        long oldDurationTime = 1000;
+        for (int i = 0; i < 20; i++) {
+            String sql = "SELECT " + buildRecursiveBracketExpression("concat($1,'B')", "'A'", i) + " FROM mytbl";
+            long startTime = System.currentTimeMillis();
+            assertSqlCanBeParsedAndDeparsed(sql, true);
+            long durationTime = System.currentTimeMillis() - startTime;
+
+            if (i > 0) {
+                System.out.println("old duration " + oldDurationTime + " new duration time " + durationTime + " for " + sql);
+            }
+
+            if (oldDurationTime * 4 < durationTime) {
+                fail("too large increment of parsing time");
+            }
+
+            oldDurationTime = Math.max(durationTime, 1);
+        }
+    }
+
+    @Test
+    public void testRecursiveBracketExpression() {
+        assertEquals("concat('A','B')", buildRecursiveBracketExpression("concat($1,'B')", "'A'", 0));
+        assertEquals("concat(concat('A','B'),'B')", buildRecursiveBracketExpression("concat($1,'B')", "'A'", 1));
+        assertEquals("concat(concat(concat('A','B'),'B'),'B')", buildRecursiveBracketExpression("concat($1,'B')", "'A'", 2));
+    }
+
+    private String buildRecursiveBracketExpression(String template, String finalExpression, int depth) {
+        if (depth == 0) {
+            return template.replace("$1", finalExpression);
+        }
+        return template.replace("$1", buildRecursiveBracketExpression(template, finalExpression, depth - 1));
     }
 }