Initial commit of the ServletRequestBindingTransformer.

org.springframework.integration.http/src/main/java/org/springframework/integration/http/transformer/ServletRequestBindingTransformer.java

@@ -0,0 +1,84 @@
+/*
+ * Copyright 2002-2009 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.http.transformer;
+
+import java.util.Map;
+
+import javax.servlet.ServletRequest;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.BeanFactory;
+import org.springframework.beans.factory.BeanFactoryAware;
+import org.springframework.integration.transformer.AbstractPayloadTransformer;
+import org.springframework.util.Assert;
+import org.springframework.web.bind.ServletRequestDataBinder;
+
+/**
+ * Message Transformer that expects a {@link ServletRequest} as input and binds
+ * its parameter map to a target instance. The target instance may be a non-singleton
+ * bean as specified by the {@link #prototypeBeanName} property. Otherwise, this
+ * transformer's {@link #type} must provide a default no-arg constructor.
+ * 
+ * @author Mark Fisher
+ * @since 1.0.2
+ */
+public class ServletRequestBindingTransformer<T> extends AbstractPayloadTransformer<ServletRequest, T> implements BeanFactoryAware {
+
+	private final Class<T> targetType;
+
+	private volatile String prototypeBeanName;
+
+	private volatile BeanFactory beanFactory;
+
+
+	public ServletRequestBindingTransformer(Class<T> targetType) {
+		Assert.notNull(targetType, "targetType must not be null");
+		this.targetType = targetType;
+	}
+
+
+	public void setPrototypeBeanName(String prototypeBeanName) {
+		this.prototypeBeanName = prototypeBeanName;
+	}
+
+	public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
+		this.beanFactory = beanFactory;
+	}
+
+	@Override
+	@SuppressWarnings("unchecked")
+	protected T transformPayload(ServletRequest request) throws Exception {
+		ServletRequestDataBinder binder = new ServletRequestDataBinder(getTarget());
+		binder.bind(request);
+		// this will immediately throw any bind Exceptions
+		Map map = binder.close();
+		return (T) map.get(ServletRequestDataBinder.DEFAULT_OBJECT_NAME);
+	}
+
+	@SuppressWarnings("unchecked")
+	private Object getTarget() throws InstantiationException, IllegalAccessException {
+		if (this.prototypeBeanName == null) {
+			return this.targetType.newInstance();
+		}
+		Assert.notNull(this.beanFactory, "beanFactory is required for binding to a prototype bean");
+		if (this.beanFactory.isSingleton(this.prototypeBeanName)) {
+			throw new IllegalArgumentException("binding target bean must not be a singleton");
+		}
+		return (T) this.beanFactory.getBean(this.prototypeBeanName, this.targetType);
+	}
+
+}