Add base header mapper implementation

2014-08-08 16:48:53 +02:00
parent f2e4ad2364
commit c1d149591a
2 changed files with 123 additions and 58 deletions
--- a/spring-messaging/src/main/java/org/springframework/messaging/support/AbstractHeaderMapper.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/support/AbstractHeaderMapper.java
@@ -0,0 +1,105 @@
+/*
+ * Copyright 2002-2014 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.messaging.support;
+
+import java.util.Map;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.messaging.MessageHeaders;
+import org.springframework.util.StringUtils;
+
+/**
+ * A base {@link HeaderMapper} implementation
+ *
+ * @author Stephane Nicoll
+ * @since 4.1
+ */
+public abstract class AbstractHeaderMapper<T> implements HeaderMapper<T> {
+
+	protected final Log logger = LogFactory.getLog(getClass());
+
+	private String inboundPrefix = "";
+
+	private String outboundPrefix = "";
+
+	/**
+	 * Specify a prefix to be appended to the message header name for any
+	 * user-defined property that is being mapped into the MessageHeaders. The
+	 * default is an empty string (no prefix).
+	 */
+	public void setInboundPrefix(String inboundPrefix) {
+		this.inboundPrefix = (inboundPrefix != null ? inboundPrefix : "");
+	}
+
+	/**
+	 * Specify a prefix to be appended to the protocol property name for any
+	 * user-defined message header that is being mapped into the protocol-specific
+	 * Message. The default is an empty string (no prefix).
+	 */
+	public void setOutboundPrefix(String outboundPrefix) {
+		this.outboundPrefix = (outboundPrefix != null ? outboundPrefix : "");
+	}
+
+	/**
+	 * Generate the name to use to set the header defined by the specified {@code headerName} to
+	 * the protocol specific message.
+	 * @see #setOutboundPrefix
+	 */
+	protected String fromHeaderName(String headerName) {
+		String propertyName = headerName;
+		if (StringUtils.hasText(this.outboundPrefix) && !propertyName.startsWith(this.outboundPrefix)) {
+			propertyName = this.outboundPrefix + headerName;
+		}
+		return propertyName;
+	}
+
+	/**
+	 * Generate the name to use to set the header defined by the specified {@code propertyName} to
+	 * the {@link MessageHeaders} instance.
+	 * @see #setInboundPrefix(String)
+	 */
+	protected String toHeaderName(String propertyName) {
+		String headerName = propertyName;
+		if (StringUtils.hasText(this.inboundPrefix) && !headerName.startsWith(this.inboundPrefix)) {
+			headerName = this.inboundPrefix + propertyName;
+		}
+		return headerName;
+	}
+
+	/**
+	 * Return the header value or {@code null} if it does not exist or does not match
+	 * the requested {@code type}.
+	 */
+	protected <V> V getHeaderIfAvailable(Map<String, Object> headers, String name, Class<V> type) {
+		Object value = headers.get(name);
+		if (value == null) {
+			return null;
+		}
+		if (!type.isAssignableFrom(value.getClass())) {
+			if (logger.isWarnEnabled()) {
+				logger.warn("Skipping header '" + name + "'expected type [" + type + "], but got [" +
+						value.getClass() + "]");
+			}
+			return null;
+		}
+		else {
+			return type.cast(value);
+		}
+	}
+}