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[JPMS] Spec modularity patterns (passing lookup)
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‎java9/spec-modularity-patterns/acme-fieldreader-impl/pom.xml

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<?xml version="1.0"?>
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<project
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xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
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xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
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<modelVersion>4.0.0</modelVersion>
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<parent>
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<groupId>org.hibernate.demos.specmodules</groupId>
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<artifactId>spec-modules-parent</artifactId>
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<version>1.0-SNAPSHOT</version>
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</parent>
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<artifactId>acme-fieldreader-impl</artifactId>
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<dependencies>
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<dependency>
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<groupId>${project.groupId}</groupId>
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<artifactId>fieldreader-spec</artifactId>
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<version>${project.version}</version>
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</dependency>
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</dependencies>
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</project>

‎java9/spec-modularity-patterns/acme-fieldreader-impl/src/main/java/acme/fieldreader/impl/AcmeBootstrapDelegate.java

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package acme.fieldreader.impl;
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import fieldreader.spec.FieldValueReader;
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import fieldreader.spec.bootstrap.BootstrapDelegate;
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public class AcmeBootstrapDelegate implements BootstrapDelegate {
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@Override
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public FieldValueReader getFieldValueReader(LookupProvider lookupProvider) {
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return new FieldValueReaderImpl( lookupProvider );
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}
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}

‎java9/spec-modularity-patterns/acme-fieldreader-impl/src/main/java/acme/fieldreader/impl/FieldValueReaderImpl.java

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package acme.fieldreader.impl;
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import fieldreader.spec.FieldValueReader;
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import fieldreader.spec.bootstrap.BootstrapDelegate.LookupProvider;
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public class FieldValueReaderImpl implements FieldValueReader {
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private LookupProvider lookupProvider;
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public FieldValueReaderImpl(LookupProvider lookupProvider) {
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this.lookupProvider = lookupProvider;
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}
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@Override
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public Object getFieldValue(Object o, String fieldName) {
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try {
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return lookupProvider.getPrivateLookup( o )
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.unreflectVarHandle( o.getClass().getDeclaredField( fieldName ) )
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.get( o );
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}
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catch (Throwable e) {
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throw new RuntimeException( e );
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}
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}
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}

‎java9/spec-modularity-patterns/acme-fieldreader-impl/src/main/java/module-info.java

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module acme.fieldreader.impl {
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requires fieldreader.spec;
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provides fieldreader.spec.bootstrap.BootstrapDelegate with acme.fieldreader.impl.AcmeBootstrapDelegate;
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}

‎java9/spec-modularity-patterns/com-example-beans/pom.xml

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<?xml version="1.0"?>
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<project
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xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
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xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
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<modelVersion>4.0.0</modelVersion>
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<parent>
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<groupId>org.hibernate.demos.specmodules</groupId>
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<artifactId>spec-modules-parent</artifactId>
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<version>1.0-SNAPSHOT</version>
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</parent>
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<artifactId>com-example-beans</artifactId>
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<dependencies>
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<dependency>
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<groupId>${project.groupId}</groupId>
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<artifactId>fieldreader-spec</artifactId>
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<version>${project.version}</version>
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</dependency>
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<dependency>
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<groupId>${project.groupId}</groupId>
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<artifactId>acme-fieldreader-impl</artifactId>
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<version>${project.version}</version>
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<scope>runtime</scope>
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</dependency>
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</dependencies>
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<build>
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<plugins>
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<plugin>
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<groupId>org.codehaus.mojo</groupId>
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<artifactId>exec-maven-plugin</artifactId>
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<version>1.6.0</version>
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<executions>
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<execution>
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<phase>integration-test</phase>
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<goals>
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<goal>exec</goal>
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</goals>
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<configuration>
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<executable>java</executable>
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<longModulepath>false</longModulepath>
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<arguments>
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<argument>-ea</argument>
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<argument>--module-path</argument>
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<modulepath/>
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<argument>--module</argument>
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<argument>com.example.beans/com.example.main.FieldReaderTest</argument>
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</arguments>
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</configuration>
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</execution>
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</executions>
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</plugin>
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</plugins>
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</build>
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</project>

‎java9/spec-modularity-patterns/com-example-beans/src/main/java/com/example/beans/MyEntity.java

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package com.example.beans;
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public class MyEntity {
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private String name;
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public MyEntity(String name) {
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this.name = name;
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}
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public String getName() {
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return name;
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}
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}

‎java9/spec-modularity-patterns/com-example-beans/src/main/java/com/example/main/FieldReaderTest.java

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package com.example.main;
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import com.example.beans.MyEntity;
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import fieldreader.spec.FieldReaderApi;
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import fieldreader.spec.FieldValueReader;
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public class FieldReaderTest {
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public static void main(String[] args) {
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FieldValueReader fieldValueReader = FieldReaderApi.getFieldValueReader();
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Object value = fieldValueReader.getFieldValue( new MyEntity( "bob" ), "name" );
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assert "bob".equals( value );
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}
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}

‎java9/spec-modularity-patterns/com-example-beans/src/main/java/module-info.java

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module com.example.beans {
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requires fieldreader.spec;
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opens com.example.beans to fieldreader.spec;
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}

‎java9/spec-modularity-patterns/fieldreader-spec/pom.xml

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<?xml version="1.0"?>
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<project
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xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
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xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
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<modelVersion>4.0.0</modelVersion>
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<parent>
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<groupId>org.hibernate.demos.specmodules</groupId>
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<artifactId>spec-modules-parent</artifactId>
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<version>1.0-SNAPSHOT</version>
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</parent>
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<artifactId>fieldreader-spec</artifactId>
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<name>spec-api</name>
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</project>

‎java9/spec-modularity-patterns/fieldreader-spec/src/main/java/fieldreader/spec/FieldReaderApi.java

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package fieldreader.spec;
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import java.lang.invoke.MethodHandles;
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import java.lang.invoke.MethodHandles.Lookup;
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import java.util.ServiceLoader;
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import fieldreader.spec.bootstrap.BootstrapDelegate;
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import fieldreader.spec.bootstrap.BootstrapDelegate.LookupProvider;
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public class FieldReaderApi {
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private static final LookupProvider LOOKUP_PROVIDER = new LookupProviderImpl();
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public static FieldValueReader getFieldValueReader() {
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ServiceLoader<BootstrapDelegate> loader = ServiceLoader.load( BootstrapDelegate.class );
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return loader.findFirst()
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.orElseThrow( () -> new IllegalStateException( "No provider of " + BootstrapDelegate.class.getName() + " available" ) )
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.getFieldValueReader( LOOKUP_PROVIDER );
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}
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private static class LookupProviderImpl implements BootstrapDelegate.LookupProvider {
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private final ClassValue<Lookup> classValue;
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private LookupProviderImpl() {
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classValue = new ClassValue<Lookup>() {
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@Override
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protected Lookup computeValue(Class<?> type) {
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FieldValueReader.class.getModule().addReads( type.getModule() );
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try {
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return MethodHandles.privateLookupIn( type, MethodHandles.lookup() );
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}
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catch (IllegalAccessException e) {
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throw new RuntimeException( e );
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}
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}
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};
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}
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@Override
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public Lookup getPrivateLookup(Object o) {
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return classValue.get( o.getClass() );
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}
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}
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}

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