Added AbstractPollingInboundChannelAdapterParser.

org.springframework.integration/src/main/java/org/springframework/integration/config/AbstractPollingInboundChannelAdapterParser.java

@@ -0,0 +1,103 @@
+/*
+ * Copyright 2002-2008 the original author or authors.
+ *
+ * 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 org.springframework.integration.config;
+
+import org.w3c.dom.Element;
+
+import org.springframework.beans.factory.BeanDefinitionStoreException;
+import org.springframework.beans.factory.config.BeanDefinitionHolder;
+import org.springframework.beans.factory.support.AbstractBeanDefinition;
+import org.springframework.beans.factory.support.BeanDefinitionBuilder;
+import org.springframework.beans.factory.support.BeanDefinitionReaderUtils;
+import org.springframework.beans.factory.xml.AbstractBeanDefinitionParser;
+import org.springframework.beans.factory.xml.ParserContext;
+import org.springframework.integration.ConfigurationException;
+import org.springframework.integration.channel.DirectChannel;
+import org.springframework.integration.endpoint.InboundChannelAdapter;
+import org.springframework.integration.scheduling.PollingSchedule;
+import org.springframework.util.StringUtils;
+import org.springframework.util.xml.DomUtils;
+
+/**
+ * Base parser for inbound Channel Adapters that poll a source.
+ * 
+ * @author Mark Fisher
+ */
+public abstract class AbstractPollingInboundChannelAdapterParser extends AbstractBeanDefinitionParser {
+
+	@Override
+	protected String resolveId(Element element, AbstractBeanDefinition definition, ParserContext parserContext) throws BeanDefinitionStoreException {
+		String id = element.getAttribute("id");
+		if (!element.hasAttribute("channel")) {
+			// the created channel will get the 'id', so the adapter's bean name includes a suffix
+			id = id + ".adapter";
+		}
+		else if (!StringUtils.hasText(id)) {
+			id = parserContext.getReaderContext().generateBeanName(definition);
+		}
+		return id;
+	}
+
+	@Override
+	protected AbstractBeanDefinition parseInternal(Element element, ParserContext parserContext) {
+		String source = this.parseSource(element, parserContext);
+		if (!StringUtils.hasText(source)) {
+			throw new ConfigurationException("failed to parse source");
+		}
+		String channelName = element.getAttribute("channel");
+		Element pollerElement = DomUtils.getChildElementByTagName(element, "poller");
+		BeanDefinitionBuilder adapterBuilder = BeanDefinitionBuilder.genericBeanDefinition(InboundChannelAdapter.class);
+		adapterBuilder.addPropertyReference("source", source);
+		if (StringUtils.hasText(channelName)) {
+			adapterBuilder.addPropertyReference("channel", channelName);
+		}
+		else {
+			adapterBuilder.addPropertyReference("channel", this.createDirectChannel(element, parserContext));
+		}
+		if (pollerElement != null) {
+			IntegrationNamespaceUtils.configureSchedule(pollerElement, adapterBuilder);
+			IntegrationNamespaceUtils.setValueIfAttributeDefined(adapterBuilder, pollerElement, "max-messages-per-poll");
+			Element txElement = DomUtils.getChildElementByTagName(pollerElement, "transactional");
+			if (txElement != null) {
+				IntegrationNamespaceUtils.configureTransactionAttributes(txElement, adapterBuilder);
+			}
+		}
+		else {
+			adapterBuilder.addPropertyValue("schedule", new PollingSchedule(0));
+		}
+		return adapterBuilder.getBeanDefinition();
+	}
+
+	/**
+	 * Subclasses must implement this method to parse the PollableSource instance
+	 * which the created Channel Adapter will poll.
+	 */
+	protected abstract String parseSource(Element element, ParserContext parserContext);
+
+	private String createDirectChannel(Element element, ParserContext parserContext) {
+		String channelId = element.getAttribute("id");
+		if (!StringUtils.hasText(channelId)) {
+			throw new ConfigurationException("The channel-adapter's 'id' attribute is required when no 'channel' "
+					+ "reference has been provided, because that 'id' would be used for the created channel.");
+		}
+		BeanDefinitionBuilder channelBuilder = BeanDefinitionBuilder.genericBeanDefinition(DirectChannel.class);
+		BeanDefinitionHolder holder = new BeanDefinitionHolder(channelBuilder.getBeanDefinition(), channelId);
+		BeanDefinitionReaderUtils.registerBeanDefinition(holder, parserContext.getRegistry());
+		return channelId;
+	}
+
+}