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- /*
- * Copyright (c) 2006-2017 DMDirc Developers
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
- * documentation files (the "Software"), to deal in the Software without restriction, including without limitation the
- * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
- * permit persons to whom the Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the
- * Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
- * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
- * OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
- * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
- */
-
- package com.dmdirc.config;
-
- import com.dmdirc.interfaces.config.AggregateConfigProvider;
- import com.dmdirc.interfaces.config.ConfigChangeListener;
-
- import com.google.common.collect.ArrayListMultimap;
- import com.google.common.collect.Multimap;
-
- import java.lang.reflect.AccessibleObject;
- import java.lang.reflect.Executable;
- import java.lang.reflect.Field;
- import java.util.ArrayList;
- import java.util.Arrays;
- import java.util.Collection;
- import java.util.Optional;
-
- import javax.annotation.Nonnull;
-
- import org.slf4j.Logger;
- import org.slf4j.LoggerFactory;
-
- import static com.dmdirc.util.LogUtils.APP_ERROR;
-
- /**
- * Facilitates automatically binding fields or methods annotated with a {@link ConfigBinding}
- * element to a configuration value.
- */
- class ConfigBinderImpl implements ConfigBinder {
-
- private static final Logger LOG = LoggerFactory.getLogger(ConfigBinder.class);
-
- /** A map of instances to created listeners. */
- private final Multimap<Object, ConfigChangeListener> listeners = ArrayListMultimap.create();
- /** The default domain to use. */
- private final Optional<String> defaultDomain;
- /** The configuration manager to use to retrieve settings. */
- private final AggregateConfigProvider manager;
- /** Retriever to use to get typed config values. */
- private final ConfigValueRetriever valueRetriever;
-
- ConfigBinderImpl(final AggregateConfigProvider manager) {
- this.manager = manager;
- this.valueRetriever = new ConfigValueRetriever(manager);
- this.defaultDomain = Optional.empty();
- }
-
- ConfigBinderImpl(final AggregateConfigProvider manager, @Nonnull final String domain) {
- this.manager = manager;
- this.valueRetriever = new ConfigValueRetriever(manager);
- this.defaultDomain = Optional.of(domain);
- }
-
- @Override
- public void bind(final Object instance, final Class<?> clazz) {
- final Collection<ConfigChangeListener> newListeners = new ArrayList<>();
- final Collection<AccessibleObject> elements = new ArrayList<>();
-
- elements.addAll(Arrays.asList(clazz.getDeclaredMethods()));
- elements.addAll(Arrays.asList(clazz.getDeclaredFields()));
-
- for (AccessibleObject element : elements) {
- final ConfigBinding binding = element.getAnnotation(ConfigBinding.class);
- if (binding != null) {
- final ConfigChangeListener listener = getListener(instance, element, binding);
- newListeners.add(listener);
-
- manager.addChangeListener(getDomain(binding.domain()), binding.key(), listener);
-
- for (int i = 0; i < binding.fallbacks().length - 1; i += 2) {
- manager.addChangeListener(getDomain(binding.fallbacks()[i]),
- binding.fallbacks()[i + 1], listener);
- }
-
- if (binding.applyInitially()) {
- updateBoundMember(instance, element, binding);
- }
- }
- }
-
- addListeners(instance, newListeners);
- }
-
- /**
- * Returns the default domain for this binder if the given annotation-specified domain is empty.
- */
- private String getDomain(final String annotationDomain) {
- return annotationDomain.isEmpty() ? defaultDomain.get() : annotationDomain;
- }
-
- /**
- * Creates a new listener which will call
- * {@link #updateBoundMember(Object, AccessibleObject, ConfigBinding)} with the given arguments.
- *
- * @param instance The instance to create a listener for
- * @param element The element to create a listener for
- * @param binding The binding annotation on the above element
- *
- * @return An appropriate config change listener
- */
- private ConfigChangeListener getListener(final Object instance,
- final AccessibleObject element, final ConfigBinding binding) {
- return (domain, key) -> updateBoundMember(instance, element, binding);
- }
-
- /**
- * Updates the specified element of the given instance with the current value of the
- * configuration key(s) specified by its binding.
- *
- * @param instance The instance to be updated
- * @param element The element to be updated
- * @param binding The binding which defines the configuration properties
- */
- private void updateBoundMember(final Object instance,
- final AccessibleObject element, final ConfigBinding binding) {
- if (!element.isAccessible()) {
- element.setAccessible(true);
- }
-
- final Object value = valueRetriever.getValue(
- getTargetClass(element),
- getDomain(binding.domain()),
- binding.key(),
- binding.required(),
- binding.fallbacks());
-
- try {
- binding.invocation().newInstance().invoke(element, instance, value);
- } catch (ReflectiveOperationException ex) {
- LOG.error(APP_ERROR, "Exception when updating bound setting", ex);
- }
- }
-
- /**
- * Gets the type required for setting the given element.
- *
- * @param element The element to determine a type for
- *
- * @return If the given element is a field, then the type of that field; if the element is a
- * method then the type of the first parameter; otherwise, <code>String.class</code>.
- */
- private Class<?> getTargetClass(final AccessibleObject element) {
- if (element instanceof Field) {
- return ((Field) element).getType();
- }
-
- if (element instanceof Executable) {
- return ((Executable) element).getParameterTypes()[0];
- }
-
- return String.class;
- }
-
- /**
- * Adds the given listeners to the given instance's collection.
- *
- * @param instance The instance to add listeners for
- * @param newListeners The listeners to be added
- */
- private void addListeners(final Object instance,
- final Iterable<ConfigChangeListener> newListeners) {
- synchronized (listeners) {
- listeners.putAll(instance, newListeners);
- }
- }
-
- @Override
- public void unbind(final Object instance) {
- synchronized (listeners) {
- listeners.get(instance).forEach(manager::removeListener);
- listeners.removeAll(instance);
- }
- }
-
- @Override
- public ConfigBinder withDefaultDomain(@Nonnull final String domain) {
- return new ConfigBinderImpl(manager, domain);
- }
-
- }
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