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

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// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
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package org.apache.juneau.rest;

import static org.apache.juneau.rest.HttpRuntimeException.*;

import java.lang.reflect.*;

import org.apache.juneau.*;
import org.apache.juneau.http.exception.*;
import org.apache.juneau.mstat.*;
import org.apache.juneau.reflect.*;
import org.apache.juneau.utils.*;

/**
 * A specialized invoker for methods that are called during a servlet request.
 */
public class RestMethodInvoker extends MethodInvoker {

	private final RestParam[] params;

	/**
	 * Constructor.
	 *
	 * @param m The method being wrapped.
	 * @param params The parameter resolvers.
	 * @param stats The instrumentor.
	 */
	public RestMethodInvoker(Method m, RestParam[] params, MethodExecStats stats) {
		super(m, stats);
		this.params = params;
	}

	/**
	 * Invokes this method from the specified {@link RestCall}.
	 *
	 * @param call The REST call.
	 * @param resource The REST resource object.
	 * @return The results of the call.
	 * @throws HttpException If an error occurred during either parameter resolution or method invocation.
	 */
	public Object invokeFromCall(RestCall call, Object resource) throws HttpException {
		Object[] args = new Object[params.length];
		for (int i = 0; i < params.length; i++) {
			ParamInfo pi = inner().getParam(i);
			try {
				args[i] = params[i].resolve(call);
			} catch (Exception e) {
				throw toHttpException(e, BadRequest.class, "Could not resolve parameter {0} of type ''{1}'' on method ''{2}''.", i, pi.getParameterType(), getFullName());
			}
		}
		try {
			return invoke(resource, args);
		} catch (ExecutableException e) {
			throw toHttpException(e.unwrap(), InternalServerError.class, "Method ''{0}'' threw an unexpected exception.", getFullName());
		}
	}
}