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 * Copyright 2014 Red Hat, Inc., and individual contributors
 * as indicated by the @author tags.
 *
 * 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
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package io.undertow.servlet.attribute;

import io.undertow.attribute.ExchangeAttribute;
import io.undertow.attribute.ExchangeAttributeBuilder;
import io.undertow.attribute.ReadOnlyAttributeException;
import io.undertow.server.HttpServerExchange;
import io.undertow.servlet.handlers.ServletRequestContext;

import java.util.HashMap;
import java.util.Map;

An attribute in the servlet request
Author:Stuart Douglas
/** * An attribute in the servlet request * * @author Stuart Douglas */
public class ServletRequestAttribute implements ExchangeAttribute { private final String attributeName; public ServletRequestAttribute(final String attributeName) { this.attributeName = attributeName; } @Override public String readAttribute(final HttpServerExchange exchange) { ServletRequestContext context = exchange.getAttachment(ServletRequestContext.ATTACHMENT_KEY); if (context != null) { Object result = context.getServletRequest().getAttribute(attributeName); if (result != null) { return result.toString(); } } else { Map<String, String> attrs = exchange.getAttachment(HttpServerExchange.REQUEST_ATTRIBUTES); if(attrs != null) { return attrs.get(attributeName); } } return null; } @Override public void writeAttribute(final HttpServerExchange exchange, final String newValue) throws ReadOnlyAttributeException { ServletRequestContext context = exchange.getAttachment(ServletRequestContext.ATTACHMENT_KEY); if (context != null) { context.getServletRequest().setAttribute(attributeName, newValue); } else { Map<String, String> attrs = exchange.getAttachment(HttpServerExchange.REQUEST_ATTRIBUTES); if(attrs == null) { exchange.putAttachment(HttpServerExchange.REQUEST_ATTRIBUTES, attrs = new HashMap<>()); } attrs.put(attributeName, newValue); } } public static final class Builder implements ExchangeAttributeBuilder { @Override public String name() { return "Servlet request attribute"; } @Override public ExchangeAttribute build(final String token) { if (token.startsWith("%{r,") && token.endsWith("}")) { final String attributeName = token.substring(4, token.length() - 1); return new ServletRequestAttribute(attributeName); } return null; } @Override public int priority() { return 0; } } }