JBehaveNeedleConfiguration.java

package org.jbehave.core.steps.needle.configuration;

import java.util.HashSet;
import java.util.ResourceBundle;
import java.util.Set;

import org.needle4j.injection.InjectionProvider;
import org.needle4j.injection.InjectionProviderInstancesSupplier;

/**
 * Reads jbehave-needle.properties to initialize additional {@link InjectionProvider}s.
 * 
 * @author Jan Galinski, Holisticon AG (jan.galinski@holisticon.de)
 * @author Simon Zambrovski, Holisticon AG (simon.zambrovski@holisticon.de)
 */
public class JBehaveNeedleConfiguration {
	/**
	 * Default properties field name.
	 */
	public static final String RESOURCE_JBEHAVE_NEEDLE = "jbehave-needle";

	private final LoadResourceBundle loadResourceBundle = LoadResourceBundle.INSTANCE;
	private final ReadInjectionProviderClassNames readInjectionProviderClassNames = ReadInjectionProviderClassNames.INSTANCE;
	private final CreateInstanceByDefaultConstructor createInstance = CreateInstanceByDefaultConstructor.INSTANCE;

	private final Set<InjectionProvider<?>> injectionProviders = new HashSet<InjectionProvider<?>>();

	/**
	 * Creates new instance from default resource {@link #RESOURCE_JBEHAVE_NEEDLE}.
	 */
	public JBehaveNeedleConfiguration() {
		this(RESOURCE_JBEHAVE_NEEDLE);
	}

	public JBehaveNeedleConfiguration(final String resourceName) {
		final ResourceBundle resourceBundle = loadResourceBundle.apply(resourceName);
		final Set<String> classNames = readInjectionProviderClassNames.apply(resourceBundle);

		for (final String className : classNames) {
			try {
				final Class<?> clazz = Class.forName(className);
				if (isInjectionProvider(clazz)) {
					injectionProviders.add((InjectionProvider<?>) createInstance.apply(clazz));
				} else if (isInjectionProviderInstanceSupplier(clazz)) {
					final InjectionProviderInstancesSupplier supplier = (InjectionProviderInstancesSupplier) createInstance
							.apply(clazz);
					final Set<InjectionProvider<?>> providers = supplier.get();
					if (providers != null) {
						injectionProviders.addAll(providers);
					}
				}
			} catch (final Exception e) {
				throw new IllegalStateException("failed to initialize custom injection providers", e);
			}
		}
	}

	public InjectionProvider<?>[] getInjectionProviders() {
		return injectionProviders.toArray(new InjectionProvider<?>[injectionProviders.size()]);
	}

	/**
	 * Checks if given class is an {@link InjectionProvider}
	 * 
	 * @param type
	 *            Class to check
	 * @return <code>true</code> if type can be cast to {@link InjectionProvider}
	 */
	static boolean isInjectionProvider(final Class<?> type) {
		return InjectionProvider.class.isAssignableFrom(type);
	}

	/**
	 * Checks if given class is an {@link InjectionProviderInstancesSupplier}
	 * 
	 * @param type
	 *            Class to check
	 * @return <code>true</code> if type can be cast to {@link InjectionProviderInstancesSupplier}
	 */
	static boolean isInjectionProviderInstanceSupplier(final Class<?> type) {
		return InjectionProviderInstancesSupplier.class.isAssignableFrom(type);
	}
}