From 02723131139806c761539a42a5fa80b68ecadee8 Mon Sep 17 00:00:00 2001
From: Vitaly Takmazov
Date: Thu, 29 Jun 2017 14:03:04 +0300
Subject: project structure: split server into jdbc + web

---
 .../main/java/com/juick/database/MySqlUpdater.java | 135 +++++++++++++++++++++
 1 file changed, 135 insertions(+)
 create mode 100644 juick-server-jdbc/src/main/java/com/juick/database/MySqlUpdater.java

(limited to 'juick-server-jdbc/src/main/java/com/juick/database')

diff --git a/juick-server-jdbc/src/main/java/com/juick/database/MySqlUpdater.java b/juick-server-jdbc/src/main/java/com/juick/database/MySqlUpdater.java
new file mode 100644
index 00000000..2027d9f1
--- /dev/null
+++ b/juick-server-jdbc/src/main/java/com/juick/database/MySqlUpdater.java
@@ -0,0 +1,135 @@
+package com.juick.database;
+
+import org.apache.commons.io.IOUtils;
+import org.apache.commons.lang3.StringUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.transaction.PlatformTransactionManager;
+import org.springframework.transaction.support.TransactionTemplate;
+import org.springframework.util.Assert;
+
+import javax.annotation.PostConstruct;
+import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Supplier;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import static org.springframework.transaction.TransactionDefinition.PROPAGATION_REQUIRED;
+
+/**
+ * Created by aalexeev on 12/13/16.
+ */
+public class MySqlUpdater {
+    private static final Pattern UPDATE_PATTERN = Pattern.compile(
+            "update\\s+(version|`version`)\\s+set\\s+(version|`version`)\\s+=\\s*(\\d+)",
+            Pattern.CASE_INSENSITIVE);
+
+    private final Logger logger = LoggerFactory.getLogger(getClass());
+
+    private final JdbcTemplate jdbcTemplate;
+    private final TransactionTemplate transactionTemplate;
+    private final String updateSqlResource;
+
+
+    public MySqlUpdater(JdbcTemplate jdbcTemplate, PlatformTransactionManager transactionManager, String updateSqlResource) {
+        Assert.notNull(jdbcTemplate, "JdbcTemplate must be initialized");
+        Assert.notNull(transactionManager, "PlatformTransactionManager must be initialized");
+        Assert.notNull(updateSqlResource, "sqlResource must be initialized");
+
+        this.jdbcTemplate = jdbcTemplate;
+        this.transactionTemplate = new TransactionTemplate(transactionManager);
+        this.updateSqlResource = updateSqlResource;
+    }
+
+    @PostConstruct
+    public void init() {
+        try (
+                InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream(updateSqlResource);
+        ) {
+            if (is != null) {
+                String content = IOUtils.toString(is, StandardCharsets.UTF_8);
+                if (StringUtils.isNotEmpty(content)) {
+                    String[] sqlArray = content.split(";");
+                    if (sqlArray.length > 0) {
+                        List<String> sqlList = new ArrayList<>(sqlArray.length);
+                        for (String sql : sqlArray)
+                            if (!sql.isEmpty()) {
+                                String sqlTrimmed = sql.trim();
+                                if (!sqlTrimmed.isEmpty())
+                                    sqlList.add(sqlTrimmed);
+                            }
+                        if (!sqlList.isEmpty())
+                            processingSql(sqlList);
+                    }
+                }
+            }
+        } catch (Exception e) {
+            logger.error("MySqlUpdater initialization exception", e);
+        }
+    }
+
+    private void processingSql(final List<String> sqls) {
+        long currentDbVersion = getSingleResult(this::getVersionRaw);
+        long actualVersion;
+
+        List<String> changesSql = new ArrayList<>();
+
+        for (String sql : sqls) {
+            changesSql.add(sql);
+
+            Matcher m = UPDATE_PATTERN.matcher(sql);
+            if (m.matches()) {
+                actualVersion = Long.valueOf(m.group(3));
+
+                if (actualVersion > currentDbVersion) {
+                    updateInTransaction(changesSql);
+                    currentDbVersion = actualVersion;
+                }
+                changesSql.clear();
+            }
+        }
+    }
+
+    private void updateInTransaction(final List<String> sqls) {
+        transactionTemplate.setReadOnly(false);
+        transactionTemplate.setPropagationBehavior(PROPAGATION_REQUIRED);
+        transactionTemplate.execute(status -> {
+            for (String sql : sqls)
+                jdbcTemplate.execute(sql);
+            return 0;
+        });
+    }
+
+    private <T> T getSingleResult(Supplier<T> supplier) {
+        transactionTemplate.setReadOnly(true);
+        transactionTemplate.setPropagationBehavior(PROPAGATION_REQUIRED);
+
+        return transactionTemplate.execute(status -> supplier.get());
+    }
+
+    private long getVersionRaw() {
+        int cnt = jdbcTemplate.query(
+                "SELECT count(*) FROM information_schema.tables WHERE table_schema = ? AND table_name = ?",
+                rs -> {
+                    int result = 0;
+                    if (rs.next())
+                        result = rs.getInt(1);
+                    return result;
+                },
+                "juick", "version");
+
+        long version = 0l;
+
+        if (cnt == 1) {
+            List<Long> list = jdbcTemplate.queryForList("select version from version", Long.class);
+            if (!list.isEmpty())
+                version = list.get(0);
+        }
+
+        return version;
+    }
+}
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