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Add caching to JavaParser.fromJavaVersion() #6026

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Merged
merged 4 commits into from
Sep 24, 2025
Merged

Add caching to JavaParser.fromJavaVersion() #6026

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34f220b
Add caching to `JavaParser.fromJavaVersion()`
knutwannheden Sep 10, 2025
9d4297f
Polish
knutwannheden Sep 11, 2025
753d8fd
Also use DCL for RuntimeClasspathCache
knutwannheden Sep 11, 2025
c731551
Merge branch 'main' into cache-java-parser-from-java-version
knutwannheden Sep 22, 2025
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167 changes: 94 additions & 73 deletions rewrite-java/src/main/java/org/openrewrite/java/JavaParser.java
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@
package org.openrewrite.java;

import io.github.classgraph.ClassGraph;
import lombok.experimental.UtilityClass;
import org.intellij.lang.annotations.Language;
import org.jspecify.annotations.Nullable;
import org.openrewrite.*;
Expand All @@ -29,12 +30,14 @@
import org.openrewrite.style.NamedStyles;

import java.io.ByteArrayInputStream;
import java.lang.reflect.Method;
import java.net.URI;
import java.nio.charset.Charset;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.*;
import java.util.function.Function;
import java.util.function.Supplier;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Stream;
Expand Down Expand Up @@ -156,67 +159,7 @@ static List<Path> dependenciesFromResources(ExecutionContext ctx, String... arti
* Builds a Java parser with a language level equal to that of the JDK running this JVM process.
*/
static JavaParser.Builder<? extends JavaParser, ?> fromJavaVersion() {
String[] versionParts = System.getProperty("java.version").split("[.-]");
int version = Integer.parseInt(versionParts[0]);
if (version == 1) {
version = 8;
}

if (version > 21) {
try {
return (JavaParser.Builder<? extends JavaParser, ?>) Class
.forName("org.openrewrite.java.Java25Parser")
.getDeclaredMethod("builder")
.invoke(null);
} catch (Throwable e) {
//Fall through, look for a parser on an older version.
}
}

if (version > 17) {
try {
return (JavaParser.Builder<? extends JavaParser, ?>) Class
.forName("org.openrewrite.java.Java21Parser")
.getDeclaredMethod("builder")
.invoke(null);
} catch (Throwable e) {
//Fall through, look for a parser on an older version.
}
}

if (version > 11) {
try {
return (JavaParser.Builder<? extends JavaParser, ?>) Class
.forName("org.openrewrite.java.Java17Parser")
.getDeclaredMethod("builder")
.invoke(null);
} catch (Throwable e) {
//Fall through, look for a parser on an older version.
}
}

if (version > 8) {
try {
return (JavaParser.Builder<? extends JavaParser, ?>) Class
.forName("org.openrewrite.java.Java11Parser")
.getDeclaredMethod("builder")
.invoke(null);
} catch (Throwable e) {
//Fall through, look for a parser on an older version.
}
}

try {
return (JavaParser.Builder<? extends JavaParser, ?>) Class
.forName("org.openrewrite.java.Java8Parser")
.getDeclaredMethod("builder")
.invoke(null);
} catch (Throwable e) {
//Fall through to an exception without making this the "cause".
}

throw new IllegalStateException("Unable to create a Java parser instance. " +
"`rewrite-java-8`, `rewrite-java-11`, `rewrite-java-17`, `rewrite-java-21`, or `rewrite-java-25` must be on the classpath.");
return JdkParserBuilderCache.getBuilder();
}

@Override
Expand Down Expand Up @@ -428,22 +371,100 @@ static Path resolveSourcePathFromSourceText(Path prefix, String sourceCode) {
}
}

@UtilityClass
class RuntimeClasspathCache {
private RuntimeClasspathCache() {
}

@Nullable
private static List<Path> runtimeClasspath = null;
private static volatile List<Path> runtimeClasspath = null;

static List<Path> getRuntimeClasspath() {
if (runtimeClasspath == null) {
runtimeClasspath = new ClassGraph()
.disableNestedJarScanning()
.getClasspathURIs().stream()
.filter(uri -> "file".equals(uri.getScheme()))
.map(Paths::get)
.collect(toList());
List<Path> paths = runtimeClasspath;
if (paths == null) {
synchronized (RuntimeClasspathCache.class) {
paths = runtimeClasspath;
if (paths == null) {
runtimeClasspath = paths = new ClassGraph()
.disableNestedJarScanning()
.getClasspathURIs().stream()
.filter(uri -> "file".equals(uri.getScheme()))
.map(Paths::get)
.collect(toList());
}
}
}
return paths;
}
}

@UtilityClass
class JdkParserBuilderCache {
// Cached supplier for the parser builder - initialized on first access
private static volatile @Nullable Supplier<JavaParser.Builder<? extends JavaParser, ?>> cachedBuilderSupplier = null;

static JavaParser.Builder<? extends JavaParser, ?> getBuilder() {
Supplier<JavaParser.Builder<? extends JavaParser, ?>> supplier = cachedBuilderSupplier;
if (supplier != null) {
return supplier.get();
}

synchronized (JdkParserBuilderCache.class) {
// Double-check after acquiring lock
supplier = cachedBuilderSupplier;
if (supplier != null) {
return supplier.get();
}

// Determine Java version once
String[] versionParts = System.getProperty("java.version").split("[.-]");
int version = Integer.parseInt(versionParts[0]);
if (version == 1) {
version = 8;
}

// Try to find and cache appropriate parser
if (version > 21) {
supplier = tryCreateBuilderSupplier("org.openrewrite.java.Java25Parser");
}

if (version > 17 && supplier == null) {
supplier = tryCreateBuilderSupplier("org.openrewrite.java.Java21Parser");
}

if (version > 11 && supplier == null) {
supplier = tryCreateBuilderSupplier("org.openrewrite.java.Java17Parser");
}

if (version > 8 && supplier == null) {
supplier = tryCreateBuilderSupplier("org.openrewrite.java.Java11Parser");
}

if (supplier == null) {
supplier = tryCreateBuilderSupplier("org.openrewrite.java.Java8Parser");
}

if (supplier != null) {
cachedBuilderSupplier = supplier;
return supplier.get();
}

throw new IllegalStateException("Unable to create a Java parser instance. " +
"`rewrite-java-8`, `rewrite-java-11`, `rewrite-java-17`, `rewrite-java-21`, or `rewrite-java-25` must be on the classpath.");
}
}

private static @Nullable Supplier<JavaParser.Builder<? extends JavaParser, ?>> tryCreateBuilderSupplier(String className) {
try {
Class<?> clazz = Class.forName(className);
Method builderMethod = clazz.getDeclaredMethod("builder");
return () -> {
try {
//noinspection rawtypes,unchecked
return (JavaParser.Builder) builderMethod.invoke(null);
} catch (Throwable e) {
throw new RuntimeException("Failed to invoke builder() on " + className, e);
}
};
} catch (ClassNotFoundException | NoSuchMethodException e) {
return null; // This parser version isn't available
}
return runtimeClasspath;
}
}