RESOLVED - issue BATCH-980: Add SystemPropertyInitializer

spring-batch-infrastructure/src/main/java/org/springframework/batch/support/SystemPropertyInitializer.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2006-2007 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.batch.support;
+
+import org.springframework.beans.factory.InitializingBean;
+import org.springframework.util.Assert;
+
+/**
+ * Helper class that sets up a System property with a default value. A System
+ * property is created with the specified key name, and default value (i.e. if
+ * the property already exists it is not changed).
+ * 
+ * @author Dave Syer
+ * 
+ */
+public class SystemPropertyInitializer implements InitializingBean {
+
+	/**
+	 * Name of system property used by default.
+	 */
+	public static final String ENVIRONMENT = "org.springframework.batch.support.SystemPropertyInitializer.ENVIRONMENT";
+
+	private String keyName = ENVIRONMENT;
+
+	private String defaultValue;
+
+	/**
+	 * Set the key name for the System property that is created. Defaults to
+	 * {@link #ENVIRONMENT}.
+	 * 
+	 * @param keyName the key name to set
+	 */
+	public void setKeyName(String keyName) {
+		this.keyName = keyName;
+	}
+
+	/**
+	 * Mandatory property specifying the default value of the System property.
+	 * 
+	 * @param defaultValue the default value to set
+	 */
+	public void setDefaultValue(String defaultValue) {
+		this.defaultValue = defaultValue;
+	}
+
+	/**
+	 * Sets the System property with the provided name and default value.
+	 * 
+	 * @see InitializingBean#afterPropertiesSet()
+	 */
+	public void afterPropertiesSet() throws Exception {
+		Assert.state(defaultValue != null || System.getProperty(keyName) != null,
+				"Either a default value must be specified or the value should already be set for System property: "
+						+ keyName);
+		System.setProperty(keyName, System.getProperty(keyName, defaultValue));
+	}
+
+}