juneau-core/juneau-marshall/src/main/java/org/apache/juneau/internal/SystemUtils.java

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// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
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// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
// *                                                                                                                         *
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// ***************************************************************************************************************************
package org.apache.juneau.internal;

/**
 * System utilities.
 */
public class SystemUtils {

	/**
	 * Returns the first non-<jk>null</jk> system property.
	 *
	 * @param def
	 * 	The default value if none are found.
	 * 	Can be <jk>null</jk>.
	 * @param keys
	 * 	The system properties to look for.
	 * @return
	 * 	The first non-<jk>null</jk> system property, or the default value if non were found.
	 */
	public static String getFirstString(String def, String...keys) {
		for (String key : keys) {
			String v = System.getProperty(key);
			if (v != null)
				return v;
		}
		return def;
	}

	/**
	 * Returns the first non-<jk>null</jk> boolean system property.
	 *
	 * @param def
	 * 	The default value if none are found.
	 * 	Can be <jk>null</jk>.
	 * @param keys
	 * 	The system properties to look for.
	 * @return
	 * 	The first non-<jk>null</jk> system property, or the default value if non were found.
	 */
	public static Boolean getFirstBoolean(Boolean def, String...keys) {
		String s = getFirstString(null, keys);
		return s == null ? def : Boolean.parseBoolean(s);
	}

	/**
	 * Returns the first non-<jk>null</jk> integer system property.
	 *
	 * @param def
	 * 	The default value if none are found.
	 * 	Can be <jk>null</jk>.
	 * @param keys
	 * 	The system properties to look for.
	 * @return
	 * 	The first non-<jk>null</jk> system property, or the default value if non were found.
	 */
	public static Integer getFirstInteger(Integer def, String...keys) {
		String s = getFirstString(null, keys);
		return s == null ? def : Integer.parseInt(s);
	}

	/**
	 * Convenience method for setting a system property value.
	 *
	 * @param key The system property key.
	 * @param value The system property value.
	 * @param overwrite Overwrite the previous value if it exists.
	 */
	public static void setProperty(String key, Object value, boolean overwrite) {
		if (value != null) {
			if (System.getProperty(key) == null || overwrite)
				System.setProperty(key, StringUtils.stringify(value));
		}
	}

	/**
	 * Convenience method for setting a system property value.
	 *
	 * @param key The system property key.
	 * @param value The system property value.
	 */
	public static void setProperty(String key, Object value) {
		setProperty(key, value, true);
	}
}