de.itsvs.cwtrpc.core.CwtRpcUtils.java Source code

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Here is the source code for de.itsvs.cwtrpc.core.CwtRpcUtils.java

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/*
 *  Copyright 2011 IT Services VS GmbH
 *
 *  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 de.itsvs.cwtrpc.core;

import java.io.IOException;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.context.ApplicationContextException;

import com.google.gwt.user.client.rpc.RpcRequestBuilder;
import com.google.gwt.user.server.rpc.RPCServletUtils;

/**
 * @author Volker Schmidt
 * @since 0.9
 */
public abstract class CwtRpcUtils {
    public static final String PRELOADED_CLASSES_INIT_PARAM_NAME = "contextLoaderPreloadedClasses";

    protected static final String GWT_RPC_REQUEST_CONTENT_ATTR_NAME = CwtRpcUtils.class.getName()
            .concat(".gwtRpcRequestContent");

    protected static final String RPC_SESSION_INVALIDATION_POLICY_ATTR_NAME = CwtRpcUtils.class.getName()
            .concat(".rpcSessionInvalidationPolicy");

    protected static final RpcSessionInvalidationPolicy defaultRpcSessionInvalidationPolicy = new DefaultRpcSessionInvalidationPolicy();

    private CwtRpcUtils() {
        super();
    }

    public static void preloadContextClasses(ServletContext servletContext) throws ApplicationContextException {
        final Log log = LogFactory.getLog(CwtRpcUtils.class);
        final String preloadedClasses;

        preloadedClasses = servletContext.getInitParameter(PRELOADED_CLASSES_INIT_PARAM_NAME);
        if (preloadedClasses != null) {
            final String[] classNames = preloadedClasses.split("\\s");

            for (String className : classNames) {
                if (className.length() > 0) {
                    if (log.isDebugEnabled()) {
                        log.debug("Preloading class: " + className);
                    }
                    try {
                        CwtRpcUtils.class.getClassLoader().loadClass(className);
                    } catch (ClassNotFoundException e) {
                        throw new ApplicationContextException("Could not load class '" + className + "'", e);
                    }
                }
            }
        }
    }

    public static boolean containsStrongName(HttpServletRequest request) {
        return (request.getHeader(RpcRequestBuilder.STRONG_NAME_HEADER) != null);
    }

    public static boolean isContentRead(HttpServletRequest request) {
        return (request.getAttribute(GWT_RPC_REQUEST_CONTENT_ATTR_NAME) != null);
    }

    public static String readContent(HttpServletRequest request)
            throws ServletException, IOException, SecurityException {
        String payload;

        /*
         * Content can only be read once from servlet request. In order to
         * access it multiple times the content must be stored in request after
         * it has been read.
         */
        payload = (String) request.getAttribute(GWT_RPC_REQUEST_CONTENT_ATTR_NAME);
        if (payload == null) {
            if (!containsStrongName(request)) {
                throw new SecurityException("Request does not contain required strong name header");
            }
            payload = RPCServletUtils.readContentAsGwtRpc(request);
            request.setAttribute(GWT_RPC_REQUEST_CONTENT_ATTR_NAME, payload);
        }

        return payload;
    }

    public static RpcSessionInvalidationPolicy getDefaultRpcSessionInvalidationPolicy() {
        return defaultRpcSessionInvalidationPolicy;
    }

    public static void saveRpcSessionInvalidationPolicy(HttpServletRequest request,
            RpcSessionInvalidationPolicy policy) {
        request.setAttribute(RPC_SESSION_INVALIDATION_POLICY_ATTR_NAME, policy);
    }

    public static boolean isRpcSessionInvalidationPolicySet(HttpServletRequest request) {
        return (request.getAttribute(RPC_SESSION_INVALIDATION_POLICY_ATTR_NAME) != null);
    }

    public static RpcSessionInvalidationPolicy getRpcSessionInvalidationPolicy(HttpServletRequest request) {
        RpcSessionInvalidationPolicy policy;

        policy = (RpcSessionInvalidationPolicy) request.getAttribute(RPC_SESSION_INVALIDATION_POLICY_ATTR_NAME);
        if (policy == null) {
            policy = getDefaultRpcSessionInvalidationPolicy();
        }
        return policy;
    }

    public static void addNoCacheResponseHeaders(HttpServletRequest request, HttpServletResponse response) {
        response.setHeader("Cache-Control", "no-cache, no-store, no-transform");
        response.setDateHeader("Expires", -1L);
        response.setHeader("Pragma", "no-cache");
    }

    protected static class DefaultRpcSessionInvalidationPolicy implements RpcSessionInvalidationPolicy {
        private static final long serialVersionUID = -1565577317645452477L;

        public boolean isInvalidateAfterInvocation() {
            return false;
        }

        public boolean isInvalidateOnUnexpectedException() {
            return false;
        }

        public boolean isInvalidateOnExpectedException() {
            return false;
        }
    }
}