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org.semanticweb.owlapi.utilities.Injector Maven / Gradle / Ivy
package org.semanticweb.owlapi.utilities;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.lang.annotation.Annotation;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Parameter;
import java.lang.reflect.ParameterizedType;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Supplier;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import javax.annotation.Nullable;
import javax.inject.Inject;
import javax.inject.Qualifier;
import javax.inject.Singleton;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Basic dependency injection utility, to replace the use of Guice and wrap calls to ServiceLoader.
*/
public class Injector {
private static final Logger LOGGER = LoggerFactory.getLogger(Injector.class);
private Map>> supplierOverrides = new ConcurrentHashMap<>();
private Map> typesOverrides = new ConcurrentHashMap<>();
private Map>> typesCache = new ConcurrentHashMap<>();
/**
* Key class for caches
*
* @author ignazio
*/
public static class Key {
Class c;
Annotation[] anns;
int hash = 0;
@Override
public boolean equals(@Nullable Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof Key)) {
return false;
}
Key k = (Key) obj;
return Objects.equals(c, k.c) && Arrays.equals(anns, k.anns);
}
/**
* @param cl class
* @param a annotations
* @return modified key
*/
public Key with(Class cl, Annotation[] a) {
c = cl;
anns = a;
hash = c.hashCode() * 37 + Arrays.hashCode(anns);
return this;
}
@Override
public int hashCode() {
return hash;
}
}
/**
* Default constructor
*/
public Injector() {}
/**
* @param i injector to copy
*/
public Injector(Injector i) {
supplierOverrides.putAll(i.supplierOverrides);
typesOverrides.putAll(i.typesOverrides);
typesCache.putAll(i.typesCache);
}
/**
* Associate a key made of interface type and optional annotations with an implementation type
*
* @param t implementation type
* @param c interface type
* @param annotations annotations
* @return modified injector
*/
public Injector bind(Class t, Class c, Annotation... annotations) {
typesOverrides.put(key(c, annotations), t);
return this;
}
/**
* Associate a key made of interface type and optional annotations with an instance, replacing
* existing associations
*
* @param t instance
* @param c interface type
* @param annotations annotations
* @return modified injector
*/
public Injector bindToOne(Object t, Class c, Annotation... annotations) {
Supplier s = () -> t;
return bindToOne(s, c, annotations);
}
/**
* Associate a key made of interface type and optional annotations with a supplier of instances,
* replacing existing associations
*
* @param t supplier
* @param c interface type
* @param annotations annotations
* @return modified injector
*/
public Injector bindToOne(Supplier t, Class c, Annotation... annotations) {
supplierOverrides.put(key(c, annotations), Collections.singletonList(t));
return this;
}
/**
* Associate a key made of interface type and optional annotations with an instance, adding to
* existing associations
*
* @param return type
* @param t instance
* @param c interface type
* @param annotations annotations
* @return modified injector
*/
public Injector bindOneMore(T t, Class c, Annotation... annotations) {
Supplier s = () -> t;
return bindOneMore(s, c, annotations);
}
/**
* Associate a key made of interface type and optional annotations with a supplier of instances,
* adding to existing associations
*
* @param return type
* @param t supplier
* @param c interface type
* @param annotations annotations
* @return modified injector
*/
public Injector bindOneMore(Supplier t, Class c, Annotation... annotations) {
supplierOverrides.computeIfAbsent(key(c, annotations), x -> new ArrayList<>()).add(t);
return this;
}
protected Object key(Class c, Annotation... annotations) {
if (annotations.length == 0) {
// for input without annotations, use the class as cache key
return c;
}
return new Key().with(c, annotations);
}
/**
* @param return type
* @param t object to inject
* @return input object with all methods annotated with @Inject having been set with instances.
*/
public T inject(T t) {
LOGGER.debug("Injecting object {}", t);
List methodsToInject = new ArrayList<>();
Class c = t.getClass();
while (c != null) {
for (Method m : c.getDeclaredMethods()) {
Inject annotation = m.getAnnotation(Inject.class);
if (annotation != null) {
methodsToInject.add(m);
}
}
c = c.getSuperclass();
}
for (Method m : methodsToInject) {
Parameter[] parameterTypes = m.getParameters();
Object[] args = new Object[parameterTypes.length];
for (int i = 0; i < parameterTypes.length; i++) {
Parameter arg = parameterTypes[i];
if (Collection.class.isAssignableFrom(arg.getType())) {
Class type = (Class) ((ParameterizedType) arg.getParameterizedType())
.getActualTypeArguments()[0];
args[i] =
load(type, qualifiers(arg.getAnnotations())).collect(Collectors.toSet());
} else {
args[i] = load(arg.getType(), qualifiers(arg.getAnnotations())).findAny()
.orElse(null);
}
}
try {
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("Injecting values {} on method {}.", Arrays.toString(args), m);
}
m.invoke(t, args);
} catch (IllegalAccessException | IllegalArgumentException
| InvocationTargetException e) {
LOGGER.error("Injection failed", e);
}
}
return t;
}
private static Annotation[] qualifiers(Annotation[] anns) {
List qualifiers = new ArrayList<>();
for (Annotation a : anns) {
if (a instanceof Qualifier
|| a.annotationType().getAnnotation(Qualifier.class) != null) {
qualifiers.add(a);
}
}
return qualifiers.toArray(new Qualifier[qualifiers.size()]);
}
/**
* @param return type
* @param c class
* @param qualifiers optional annotations
* @return instance
*/
public T getImplementation(Class c, Annotation... qualifiers) {
return load(c, qualifiers).findAny().orElse(null);
}
/**
* @param return type
* @param c class
* @param overrides local overrides of existing bindings
* @param qualifiers optional annotations
* @return instance
*/
public T getImplementation(Class c, Map>> overrides,
Annotation... qualifiers) {
Injector i = new Injector(this);
overrides.forEach((a, b) -> i.supplierOverrides.put(a, b));
return i.getImplementation(c, qualifiers);
}
protected List classLoaders() {
// in OSGi, the context class loader is likely null.
// This would trigger the use of the system class loader, which would
// not see the OWLAPI jar, nor any other jar containing implementations.
// In that case, use this class classloader to load, at a minimum, the
// services provided by the OWLAPI jar itself.
return Arrays.asList(Thread.currentThread().getContextClassLoader(),
ClassLoader.getSystemClassLoader(), getClass().getClassLoader());
}
/**
* @param type type to load
* @param qualifiers qualifying annotations
* @param return type
* @return iterable over T implementations
*/
protected Stream load(Class type, Annotation... qualifiers) {
Object key = key(type, qualifiers);
Class c = typesOverrides.get(key);
if (c != null) {
return Stream.of(type.cast(instantiate(c, key)));
}
List> suppliers = supplierOverrides.getOrDefault(key, Collections.emptyList());
if (!suppliers.isEmpty()) {
// cached suppliers
return suppliers.stream().map(Supplier::get).map(type::cast);
}
List> cached = typesCache.getOrDefault(key, Collections.emptyList());
if (!cached.isEmpty()) {
return cached.stream().map(s -> instantiate(s, key)).map(type::cast);
}
String name = "META-INF/services/" + type.getName();
LOGGER.debug("Loading file {}", name);
// J2EE compatible search
return urls(name).flatMap(this::entries).distinct()
.map(s -> (Class) prepareClass(s, key)).map(s -> instantiate(s, key));
}
private static Constructor injectableConstructor(Class c) {
try {
Constructor[] constructors = c.getConstructors();
if (constructors.length == 1) {
return (Constructor) constructors[0];
}
Optional> findAny = Arrays.stream(constructors)
.filter(m -> m.getAnnotation(Inject.class) != null).findAny();
if (!findAny.isPresent()) {
LOGGER.error("No injectable constructor found for {}", c);
}
return (Constructor) findAny.orElse(null);
} catch (SecurityException e) {
LOGGER.error("No injectable constructor found for {} because of security restrictions",
c);
return null;
}
}
private Object[] paramInstances(Parameter[] params) {
Object[] toReturn = new Object[params.length];
for (int i = 0; i < toReturn.length; i++) {
Iterator iterator = load(params[i].getType(), params[i].getAnnotations()).iterator();
if (iterator.hasNext()) {
toReturn[i] = iterator.next();
} else {
LOGGER.error("No instantiation found for {}", params[i]);
}
}
return toReturn;
}
private Class prepareClass(String s, Object key) {
try {
Class forName = Class.forName(s);
typesCache.computeIfAbsent(key, x -> new ArrayList<>()).add(forName);
return (Class) forName;
} catch (ClassNotFoundException | IllegalArgumentException | SecurityException e) {
LOGGER.error("Instantiation failed", e);
return null;
}
}
private T instantiate(Class s, Object key) {
try {
Constructor c = injectableConstructor(s);
if (c == null) {
LOGGER.error("Instantiation failed: no constructors found for {}", s);
return null;
}
Object[] paramInstances = paramInstances(c.getParameters());
Object newInstance = c.newInstance(paramInstances);
if (s.getAnnotation(Singleton.class) != null) {
// cache singletons for next call
supplierOverrides.put(key, Collections.singletonList(() -> newInstance));
}
return s.cast(newInstance);
} catch (InstantiationException | IllegalAccessException | IllegalArgumentException
| InvocationTargetException | SecurityException e) {
LOGGER.error("Instantiation failed", e);
return null;
}
}
private Stream urls(String name) {
List l = new ArrayList<>();
try {
for (ClassLoader cl : classLoaders()) {
if (cl != null) {
Enumeration resources = cl.getResources(name);
while (resources.hasMoreElements()) {
URL e = resources.nextElement();
l.add(e);
LOGGER.debug("Loading URL for service {}", e);
}
}
}
if (l.isEmpty()) {
LOGGER.debug("No files found for {}", name);
}
} catch (IOException e) {
LOGGER.error("Error accessing services files", e);
}
return l.stream();
}
private Stream entries(URL c) {
try (InputStream in = c.openStream();
InputStreamReader in2 = new InputStreamReader(in, StandardCharsets.UTF_8);
BufferedReader r = new BufferedReader(in2)) {
return r.lines().collect(Collectors.toList()).stream();
} catch (IOException e) {
LOGGER.error("Error reading services files: " + c, e);
}
return Stream.empty();
}
}
