ThreadI18nContextProvider.java
package dev.orne.i18n.context;
/*-
* #%L
* Orne I18N
* %%
* Copyright (C) 2021 - 2024 Orne Developments
* %%
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Lesser Public License for more details.
*
* You should have received a copy of the GNU General Lesser Public
* License along with this program. If not, see
* <http://www.gnu.org/licenses/lgpl-3.0.html>.
* #L%
*/
import java.util.Locale;
import java.util.Properties;
import java.util.function.Supplier;
import javax.validation.constraints.NotNull;
import org.apache.commons.lang3.Validate;
import org.apache.commons.lang3.builder.EqualsBuilder;
import org.apache.commons.lang3.builder.HashCodeBuilder;
import org.apiguardian.api.API;
import org.apiguardian.api.API.Status;
import dev.orne.i18n.I18nResources;
/**
* Implementation of {@code I18nContextProvider} that provides a
* different {@code I18nContext} for each thread.
*
* @author <a href="https://github.com/ihernaez">(w) Iker Hernaez</a>
* @version 2.0, 2022-12
* @see I18nContextProvider
* @since 0.1
*/
@API(status=Status.STABLE, since="0.1")
public class ThreadI18nContextProvider
extends AbstractI18nContextProvider {
/** The I18N context provider type. */
public static final String TYPE = "THREAD";
/** The {@code I18nContext}s per {@code Thread} container. */
private final @NotNull ThreadLocal<I18nContext> contexts;
/**
* Creates a new instance based on specified builder.
*
* @param builder The I18N context provider builder.
*/
protected ThreadI18nContextProvider(
@NotNull BuilderImpl<?, ?> builder) {
super(builder);
if (builder.inheritableContexts) {
this.contexts = new InheritableThreadLocal<>();
} else {
this.contexts = new ThreadLocal<>();
}
}
/**
* Creates a new {@code ThreadI18nContextProvider} instances builder.
*
* @return The {@code ThreadI18nContextProvider} instances builder.
*/
public static @NotNull Builder builder() {
return new BuilderImpl<>();
}
/**
* Returns {@code true} if the {@code I18nContext} instances will be
* inherited by child threads.
*
* @return If the {@code I18nContext} instances will be inherited by child
* threads.
*/
public boolean isInheritable() {
return this.contexts instanceof InheritableThreadLocal;
}
/**
* Returns the internal {@code I18nContext}s per {@code Thread} container.
*
* @return The {@code I18nContext}s per {@code Thread} container
*/
protected @NotNull ThreadLocal<I18nContext> getContexts() {
return this.contexts;
}
/**
* Return the {@code I18nContext} associated with the current
* {@code Thread}.
* <p>
* If no {@code I18nContext} exists for the current {@code Thread} or the
* existing one is not alive anymore a new one is created.
*
* @return The current {@code I18nContext}. Never {@code null}.
*/
public @NotNull I18nContext getContext() {
I18nContext context = this.contexts.get();
if (context == null || !isContextValid(context)) {
context = createContext();
this.contexts.set(context);
}
return context;
}
/**
* The default contexts don't expire.
*/
@Override
public boolean isContextValid(
final @NotNull I18nContext context) {
return Validate.notNull(context) == this.contexts.get() &&
getSessionUUID().equals(context.getProviderUUID());
}
/**
* {@inheritDoc}
*/
@Override
public void clearContext() {
this.contexts.remove();
}
/**
* {@inheritDoc}
*/
@Override
public int hashCode() {
return new HashCodeBuilder()
.appendSuper(super.hashCode())
.append(isInheritable())
.toHashCode();
}
/**
* {@inheritDoc}
*/
@Override
public boolean equals(final Object obj) {
if (obj == null) { return false; }
if (obj == this) { return true; }
if (!getClass().equals(obj.getClass())) { return false; }
final ThreadI18nContextProvider other = (ThreadI18nContextProvider) obj;
return new EqualsBuilder()
.appendSuper(super.equals(obj))
.append(this.isInheritable(), other.isInheritable())
.isEquals();
}
/**
* Interface for {@code ThreadI18nContextProvider} instance builders.
*
* @author <a href="https://github.com/ihernaez">(w) Iker Hernaez</a>
* @version 1.0, 2024-09
* @since 0.1
*/
public interface Builder
extends I18nContextProvider.Builder {
/**
* {@inheritDoc}
*/
@Override
default @NotNull Builder configure() {
return configure(I18nConfiguration.get());
}
/**
* {@inheritDoc}
*/
@Override
@NotNull Builder configure(
@NotNull Properties config);
/**
* {@inheritDoc}
*/
@Override
@NotNull Builder setDefaultLocaleSupplier(
@NotNull Supplier<@NotNull Locale> supplier);
/**
* {@inheritDoc}
*/
@Override
@NotNull Builder setAvailableLocales(
@NotNull Locale[] locales);
/**
* {@inheritDoc}
*/
@Override
@NotNull Builder setDefaultI18nResources(
@NotNull I18nResources resources);
/**
* {@inheritDoc}
*/
@Override
@NotNull Builder addI18nResources(
@NotNull String key,
@NotNull I18nResources resource);
/**
* Sets if the {@code I18nContext} instances will be inherited by child
* threads.
*
* @param inheritable If the {@code I18nContext} instances will be
* inherited by child threads.
* @return This builder, for method chaining.
*/
@NotNull Builder setInheritableContexts(
@NotNull boolean inheritable);
/**
* {@inheritDoc}
*/
@Override
@NotNull ThreadI18nContextProvider build();
}
/**
* Abstract builder of {@code ThreadI18nContextProvider} instances.
*
* @author <a href="https://github.com/ihernaez">(w) Iker Hernaez</a>
* @version 1.0, 2024-09
* @param <T> The type of I18N context provider build by the builder.
* @param <B> The type of builder returned for method chaining.
* @since 0.1
*/
protected static class BuilderImpl<
T extends ThreadI18nContextProvider,
B extends BuilderImpl<T, B>>
extends AbstractI18nContextProvider.BuilderImpl<T, B>
implements Builder {
/**
* If the {@code I18nContext} instances should be inherited by child
* {@code Thread}s.
*/
protected boolean inheritableContexts = true;
/**
* Creates a new instance.
*/
protected BuilderImpl() {
super();
}
/**
* {@inheritDoc}
*/
@Override
@SuppressWarnings("unchecked")
public B configure(
final @NotNull Properties config) {
super.configure(config);
configureInheritable(config);
return (B) this;
}
/**
* Configures the default language based on specified configuration.
*
* @param config The I18N configuration.
*/
protected void configureInheritable(
final @NotNull Properties config) {
if (config.containsKey(I18nConfiguration.CONTEXT_INHERITED)) {
setInheritableContexts(Boolean.valueOf(
config.getProperty(I18nConfiguration.CONTEXT_INHERITED)));
}
}
/**
* Sets if the {@code I18nContext} instances will be inherited by child
* threads.
*
* @param inheritable If the {@code I18nContext} instances will be
* inherited by child threads.
* @return This builder, for method chaining.
*/
@SuppressWarnings("unchecked")
public @NotNull B setInheritableContexts(
@NotNull boolean inheritable) {
this.inheritableContexts = inheritable;
return (B) this;
}
/**
* {@inheritDoc}
*/
@Override
public @NotNull ThreadI18nContextProvider build() {
return new ThreadI18nContextProvider(this);
}
}
/**
* Factory for {@code ThreadI18nContextProvider} instances.
*
* @author <a href="https://github.com/ihernaez">(w) Iker Hernaez</a>
* @version 1.0, 2024-08
* @since 0.1
*/
public static class Factory
implements I18nContextProviderFactory {
/**
* Creates a new instance.
*/
public Factory() {
super();
}
/**
* {@inheritDoc}
*/
@Override
public @NotNull String getType() {
return TYPE;
}
/**
* {@inheritDoc}
*/
@Override
public @NotNull ThreadI18nContextProvider create(
final @NotNull Properties config) {
return ThreadI18nContextProvider.builder()
.configure(config)
.build();
}
}
}