juneau-rest/juneau-rest-server/src/main/java/org/apache/juneau/rest/BasicRestResourceResolver.java

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package org.apache.juneau.rest;

import org.apache.juneau.internal.*;

/**
 * Denotes the default resolver for child resources.
 * 
 * The default implementation simply instantiates the class using one of the following constructors:
 * <ul>
 * 	<li><code><jk>public</jk> T(RestContextBuilder)</code>
 * 	<li><code><jk>public</jk> T()</code>
 * </ul>
 * 
 * <p>
 * The former constructor can be used to get access to the {@link RestContextBuilder} object to get access to the
 * config file and initialization information or make programmatic modifications to the resource before
 * full initialization.
 * 
 * <p>
 * Child classes can also be defined as inner-classes of the parent resource class.
 * 
 * <h5 class='section'>See Also:</h5>
 * <ul>
 * 	<li class='link'><a class="doclink" href="../../../../overview-summary.html#juneau-rest-server.ResourceResolvers">Overview &gt; juneau-rest-server &gt; Resource Resolvers</a>
 * </ul>
 */
public class BasicRestResourceResolver implements RestResourceResolver {

	@Override /* RestResourceResolver */
	public Object resolve(Object parent, Class<?> c, RestContextBuilder builder) throws Exception {
		try {
			Object r = ClassUtils.newInstanceFromOuter(parent, Object.class, c, true, builder);
			if (r != null)
				return r;
		} catch (Exception e) {
			throw new RestServletException("Could not instantiate resource class ''{0}''", c.getName()).initCause(e);
		}
		throw new RestServletException("Could not find public constructor for class ''{0}''.", c);
	}
}