Optimize hot paths: cache lists, fix integer overflow, reduce reflection

[Copilot]

Performance bottlenecks in datasource selection, load balancing, and configuration merging cause unnecessary allocations and potential crashes under high load.

Changes

GroupDataSource - Eliminate allocation in hot path

• Cache immutable list of datasource keys, rebuild only on add/remove
• Prevents ArrayList creation on every determineDsKey() call
• Uses Collections.unmodifiableList() with volatile for thread safety

LoadBalanceDynamicDataSourceStrategy - Fix overflow crash

• Replace Math.abs(index.getAndAdd(1) % size) with (index.getAndIncrement() & Integer.MAX_VALUE) % size
• Math.abs(Integer.MIN_VALUE) returns negative, causing ArrayIndexOutOfBoundsException after 2B+ requests

ConfigMergeCreator - Cache reflection results

• Add cached BeanInfo field with double-checked locking
• Eliminates repeated Introspector.getBeanInfo() calls during configuration merges
• Add null validation in constructor

DynamicRoutingDataSource - Optimize string parsing

• Replace ds.split("_")[0] with ds.substring(0, ds.indexOf("_"))
• Avoids regex compilation and array allocation for simple parsing

// Before: creates new ArrayList on every call
public String determineDsKey() {
    return strategy.determineKey(new ArrayList<>(dataSourceMap.keySet()));
}

// After: uses cached immutable list
private volatile List<String> cachedDsKeys = Collections.emptyList();
public String determineDsKey() {
    return strategy.determineKey(cachedDsKeys);
}

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• maven.aliyun.com
  • Triggering command: /usr/lib/jvm/temurin-17-jdk-amd64/bin/java /usr/lib/jvm/temurin-17-jdk-amd64/bin/java --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.lang.invoke=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED --add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-opens=java.base/java.nio.charset=ALL-UNNAMED --add-opens=java.base/java.net=ALL-UNNAMED --add-opens=java.base/java.util.concurrent.atomic=ALL-UNNAMED --add-opens=java.xml/javax.xml.namespace=ALL-UNNAMED -XX:MaxMetaspaceSize=512m -XX:+HeapDumpOnOutOfMemoryError -Xmx2048m -Dfile.encoding=UTF-8 -Duser.country -Duser.language=en -Duser.variant (dns block)
  • Triggering command: /usr/lib/jvm/temurin-8-jdk-amd64/bin/java /usr/lib/jvm/temurin-8-jdk-amd64/bin/java -XX:MaxMetaspaceSize=512m -XX:+HeapDumpOnOutOfMemoryError -Xmx2048m -Dfile.encoding=UTF-8 -Duser.country -Duser.language=en -Duser.variant -cp /home/REDACTED/.gradle/wrapper/dists/gradle-8.13-bin/5xuhj0ry160q40clulazy9h7d/gradle-8.13/lib/gradle-daemon-main-8.13.jar -javaagent:/home/REDACTED/.gradle/wrapper/dists/gradle-8.13-bin/5xuhj0ry160q40clulazy9h7d/gradle-8.13/lib/agents/gradle-instrumentation-agent-8.13.jar org.gradle.launcher.daemon.bootstrap.GradleDaemon 8.13 ng/src/main/java/com/baomidou/dynamic/datasource/DynamicRoutingDataSource.java urce-creator/src/main/java/com/btest rgo/bin/grep .split xyChecker.java /snap/bin/git r (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

Identify and suggest improvements to slow or inefficient code

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