com.boylesoftware.web.impl.routes.RoutesRouterConfiguration.java Source code

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Here is the source code for com.boylesoftware.web.impl.routes.RoutesRouterConfiguration.java

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/*
 * Copyright 2013 Boyle Software, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.boylesoftware.web.impl.routes;

import java.io.IOException;
import java.io.InputStream;

import javax.servlet.ServletContext;
import javax.servlet.UnavailableException;

import com.boylesoftware.web.ApplicationServices;
import com.boylesoftware.web.impl.AbstractRouterConfiguration;
import com.boylesoftware.web.impl.RoutesBuilder;
import com.boylesoftware.web.spi.ControllerMethodArgHandlerProvider;
import com.boylesoftware.web.spi.ViewSender;

import org.antlr.v4.runtime.ANTLRInputStream;
import org.antlr.v4.runtime.BailErrorStrategy;
import org.antlr.v4.runtime.CommonTokenStream;
import org.apache.commons.logging.LogFactory;

/**
 * Router configuration provider implementation that loads the configuration
 * from {@value #ROUTES_PATH} file.
 *
 * @author Lev Himmelfarb
 */
public class RoutesRouterConfiguration extends AbstractRouterConfiguration {

    /**
     * Context-relative path to the router configuration file.
     */
    public static final String ROUTES_PATH = "/WEB-INF/routes";

    /**
     * Create new provider.
     *
     * @param sc Servlet context.
     * @param appServices The application services.
     * @param argHandlerProvider Controller method argument handler provider.
     * @param viewSender View sender.
     *
     * @throws UnavailableException If configuration is incorrect.
     */
    public RoutesRouterConfiguration(final ServletContext sc, final ApplicationServices appServices,
            final ControllerMethodArgHandlerProvider argHandlerProvider, final ViewSender viewSender)
            throws UnavailableException {
        super(sc, appServices, argHandlerProvider, viewSender);
    }

    /* (non-Javadoc)
     * @see com.boylesoftware.web.impl.AbstractRouterConfiguration#buildRoutes(javax.servlet.ServletContext, com.boylesoftware.web.impl.RoutesBuilder)
     */
    @Override
    protected void buildRoutes(final ServletContext sc, final RoutesBuilder routes) throws UnavailableException {

        try (final InputStream in = sc.getResourceAsStream(ROUTES_PATH)) {

            if (in == null)
                throw new UnavailableException("No " + ROUTES_PATH + " found in the web-application.");

            final RoutesParser parser = new RoutesParser(
                    new CommonTokenStream(new RoutesLexer(new ANTLRInputStream(in))));
            parser.setErrorHandler(new BailErrorStrategy());
            parser.setRoutesBuilder(routes);
            try {
                parser.config();
            } catch (final Exception e) {
                this.error(e);
            }

        } catch (final IOException e) {
            this.error(e);
        }
    }

    /**
     * Convert exception to {@link UnavailableException} and throw it.
     *
     * @param e Original exception.
     *
     * @throws UnavailableException Always.
     */
    private void error(final Exception e) throws UnavailableException {

        LogFactory.getLog(this.getClass()).error("error loading router configuration", e);
        throw new UnavailableException("Error loading router configuration: " + e.getMessage());
    }
}