/**
    * Copyright 2010-2012 The Kuali Foundation
    *
    * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
    *
   * 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.kuali.common.util;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.io.Reader;
  import java.io.Writer;
  import java.nio.charset.Charset;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.Enumeration;
  import java.util.List;
  import java.util.Map;
  import java.util.Properties;
  import java.util.Set;
  import java.util.TreeSet;
  
  import org.apache.commons.io.FileUtils;
  import org.apache.commons.io.IOUtils;
  import org.apache.commons.lang3.StringUtils;
  import org.jasypt.util.text.TextEncryptor;
  import org.kuali.common.util.property.Constants;
  import org.kuali.common.util.property.GlobalPropertiesMode;
  import org.kuali.common.util.property.processor.AddPropertiesProcessor;
  import org.kuali.common.util.property.processor.PropertyProcessor;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.util.PropertyPlaceholderHelper;
  
  /**
   * Simplify handling of <code>Properties</code> especially as it relates to storing and loading. <code>Properties</code> can be loaded from any url Spring resource loading can
   * understand. When storing and loading, locations ending in <code>.xml</code> are automatically handled using <code>storeToXML()</code> and <code>loadFromXML()</code>,
   * respectively. <code>Properties</code> are always stored in sorted order with the <code>encoding</code> indicated via a comment.
   */
  public class PropertyUtils {
  
  	private static final Logger logger = LoggerFactory.getLogger(PropertyUtils.class);
  
  	private static final String XML_EXTENSION = ".xml";
  	private static final String ENV_PREFIX = "env";
  	private static final String DEFAULT_ENCODING = Charset.defaultCharset().name();
  	private static final String DEFAULT_XML_ENCODING = "UTF-8";
  
  	/**
  	 * Decrypt any encrypted property values. Encrypted values are surrounded by ENC(...), like:
  	 * 
  	 * <pre>
  	 * my.value = ENC(DGA"$S24FaIO)
  	 * </pre>
  	 */
  	public static void decrypt(Properties properties, TextEncryptor encryptor) {
  		decrypt(properties, encryptor, null, null);
  	}
  
  	/**
  	 * Return a new <code>Properties</code> object (never null) containing only those properties whose values are encrypted. Encrypted values are surrounded by ENC(...), like:
  	 * 
  	 * <pre>
  	 * my.value = ENC(DGA"$S24FaIO)
  	 * </pre>
  	 */
  	public static Properties getEncryptedProperties(Properties properties) {
  		List<String> keys = getSortedKeys(properties);
  		Properties encrypted = new Properties();
  		for (String key : keys) {
  			String value = properties.getProperty(key);
  			if (isEncryptedPropertyValue(value)) {
  				encrypted.setProperty(key, value);
  			}
  		}
  		return encrypted;
  	}
  
  	/**
  	 * Decrypt any encrypted property values matching the <code>includes</code>, <code>excludes</code> patterns. Encrypted values are surrounded by ENC(...).
  	 * 
  	 * <pre>
  	 * my.value = ENC(DGA"$S24FaIO)
  	 * </pre>
  	 */
  	public static void decrypt(Properties properties, TextEncryptor encryptor, List<String> includes, List<String> excludes) {
  		List<String> keys = getSortedKeys(properties, includes, excludes);
 		for (String key : keys) {
 			String value = properties.getProperty(key);
 			if (isEncryptedPropertyValue(value)) {
 				String decryptedValue = decryptPropertyValue(encryptor, value);
 				properties.setProperty(key, decryptedValue);
 			}
 		}
 	}
 
 	/**
 	 * Return true if the value starts with <code>ENC(</code> and ends with <code>)</code>, false otherwise.
 	 */
 	public static boolean isEncryptedPropertyValue(String value) {
 		return StringUtils.startsWith(value, Constants.ENCRYPTION_PREFIX) && StringUtils.endsWith(value, Constants.ENCRYPTION_SUFFIX);
 	}
 
 	/**
 	 * Encrypt all of the property values. Encrypted values are surrounded by ENC(...).
 	 * 
 	 * <pre>
 	 * my.value = ENC(DGA"$S24FaIO)
 	 * </pre>
 	 */
 	public static void encrypt(Properties properties, TextEncryptor encryptor) {
 		encrypt(properties, encryptor, null, null);
 	}
 
 	/**
 	 * Encrypt properties as dictated by <code>includes</code> and <code>excludes</code>. Encrypted values are surrounded by ENC(...).
 	 * 
 	 * <pre>
 	 * my.value = ENC(DGA"$S24FaIO)
 	 * </pre>
 	 */
 	public static void encrypt(Properties properties, TextEncryptor encryptor, List<String> includes, List<String> excludes) {
 		List<String> keys = getSortedKeys(properties, includes, excludes);
 		for (String key : keys) {
 			String originalValue = properties.getProperty(key);
 			String encryptedValue = encryptPropertyValue(encryptor, originalValue);
 			properties.setProperty(key, encryptedValue);
 		}
 	}
 
 	/**
 	 * Return the decrypted version of the property value. Encrypted values are surrounded by ENC(...).
 	 * 
 	 * <pre>
 	 * my.value = ENC(DGA"$S24FaIO)
 	 * </pre>
 	 */
 	public static String decryptPropertyValue(TextEncryptor encryptor, String value) {
 		// Ensure this property value really is encrypted
 		Assert.isTrue(StringUtils.startsWith(value, Constants.ENCRYPTION_PREFIX), "value does not start with " + Constants.ENCRYPTION_PREFIX);
 		Assert.isTrue(StringUtils.endsWith(value, Constants.ENCRYPTION_SUFFIX), "value does not end with " + Constants.ENCRYPTION_SUFFIX);
 
 		// Extract the value inside the ENC(...) wrapping
 		int start = Constants.ENCRYPTION_PREFIX.length();
 		int end = StringUtils.length(value) - Constants.ENCRYPTION_SUFFIX.length();
 		String unwrapped = StringUtils.substring(value, start, end);
 
 		// Return the decrypted value
 		return encryptor.decrypt(unwrapped);
 	}
 
 	/**
 	 * Return the encrypted version of the property value. A value is considered "encrypted" when it appears surrounded by ENC(...).
 	 * 
 	 * <pre>
 	 * my.value = ENC(DGA"$S24FaIO)
 	 * </pre>
 	 */
 	public static String encryptPropertyValue(TextEncryptor encryptor, String value) {
 		String encryptedValue = encryptor.encrypt(value);
 		StringBuilder sb = new StringBuilder();
 		sb.append(Constants.ENCRYPTION_PREFIX);
 		sb.append(encryptedValue);
 		sb.append(Constants.ENCRYPTION_SUFFIX);
 		return sb.toString();
 	}
 
 	public static void overrideWithGlobalValues(Properties properties, GlobalPropertiesMode mode) {
 		List<String> keys = PropertyUtils.getSortedKeys(properties);
 		Properties global = PropertyUtils.getProperties(mode);
 		for (String key : keys) {
 			String globalValue = global.getProperty(key);
 			if (!StringUtils.isBlank(globalValue)) {
 				properties.setProperty(key, globalValue);
 			}
 		}
 	}
 
 	public static final Properties combine(List<Properties> properties) {
 		Properties combined = new Properties();
 		for (Properties p : properties) {
 			combined.putAll(PropertyUtils.toEmpty(p));
 		}
 		return combined;
 	}
 
 	public static final Properties combine(Properties... properties) {
 		return combine(Arrays.asList(properties));
 	}
 
 	public static final void process(Properties properties, PropertyProcessor processor) {
 		process(properties, Collections.singletonList(processor));
 	}
 
 	public static final void process(Properties properties, List<PropertyProcessor> processors) {
 		for (PropertyProcessor processor : CollectionUtils.toEmptyList(processors)) {
 			processor.process(properties);
 		}
 	}
 
 	public static final Properties toEmpty(Properties properties) {
 		return properties == null ? new Properties() : properties;
 	}
 
 	public static final boolean isSingleUnresolvedPlaceholder(String string) {
 		return isSingleUnresolvedPlaceholder(string, Constants.DEFAULT_PLACEHOLDER_PREFIX, Constants.DEFAULT_PLACEHOLDER_SUFFIX);
 	}
 
 	public static final boolean isSingleUnresolvedPlaceholder(String string, String prefix, String suffix) {
 		int prefixMatches = StringUtils.countMatches(string, prefix);
 		int suffixMatches = StringUtils.countMatches(string, suffix);
 		boolean startsWith = StringUtils.startsWith(string, prefix);
 		boolean endsWith = StringUtils.endsWith(string, suffix);
 		return prefixMatches == 1 && suffixMatches == 1 && startsWith && endsWith;
 	}
 
 	public static final boolean containsUnresolvedPlaceholder(String string) {
 		return containsUnresolvedPlaceholder(string, Constants.DEFAULT_PLACEHOLDER_PREFIX, Constants.DEFAULT_PLACEHOLDER_SUFFIX);
 	}
 
 	public static final boolean containsUnresolvedPlaceholder(String string, String prefix, String suffix) {
 		int beginIndex = StringUtils.indexOf(string, prefix);
 		if (beginIndex == -1) {
 			return false;
 		}
 		return StringUtils.indexOf(string, suffix) != -1;
 	}
 
 	/**
 	 * Return a new <code>Properties</code> object containing only those properties where the resolved value is different from the original value. Using global properties to
 	 * perform property resolution as indicated by <code>Constants.DEFAULT_GLOBAL_PROPERTIES_MODE</code>
 	 */
 	public static final Properties getResolvedProperties(Properties properties) {
 		return getResolvedProperties(properties, Constants.DEFAULT_PROPERTY_PLACEHOLDER_HELPER, Constants.DEFAULT_GLOBAL_PROPERTIES_MODE);
 	}
 
 	/**
 	 * Return a new <code>Properties</code> object containing only those properties where the resolved value is different from the original value. Using global properties to
 	 * perform property resolution as indicated by <code>globalPropertiesMode</code>
 	 */
 	public static final Properties getResolvedProperties(Properties properties, GlobalPropertiesMode globalPropertiesMode) {
 		return getResolvedProperties(properties, Constants.DEFAULT_PROPERTY_PLACEHOLDER_HELPER, globalPropertiesMode);
 	}
 
 	/**
 	 * Return a new <code>Properties</code> object containing only those properties where the resolved value is different from the original value. Using global properties to
 	 * perform property resolution as indicated by <code>Constants.DEFAULT_GLOBAL_PROPERTIES_MODE</code>
 	 */
 	public static final Properties getResolvedProperties(Properties properties, PropertyPlaceholderHelper helper) {
 		return getResolvedProperties(properties, helper, Constants.DEFAULT_GLOBAL_PROPERTIES_MODE);
 	}
 
 	/**
 	 * Return a new <code>Properties</code> object containing only those properties where the resolved value is different from the original value. Using global properties to
 	 * perform property resolution as indicated by <code>globalPropertiesMode</code>
 	 */
 	public static final Properties getResolvedProperties(Properties properties, PropertyPlaceholderHelper helper, GlobalPropertiesMode globalPropertiesMode) {
 		Properties global = PropertyUtils.getProperties(properties, globalPropertiesMode);
 		List<String> keys = PropertyUtils.getSortedKeys(properties);
 		Properties newProperties = new Properties();
 		for (String key : keys) {
 			String originalValue = properties.getProperty(key);
 			String resolvedValue = helper.replacePlaceholders(originalValue, global);
 			if (!resolvedValue.equals(originalValue)) {
 				logger.debug("Resolved property '" + key + "' [{}] -> [{}]", Str.flatten(originalValue), Str.flatten(resolvedValue));
 				newProperties.setProperty(key, resolvedValue);
 			}
 		}
 		return newProperties;
 	}
 
 	/**
 	 * Return the property values from <code>keys</code>
 	 */
 	public static final List<String> getValues(Properties properties, List<String> keys) {
 		List<String> values = new ArrayList<String>();
 		for (String key : keys) {
 			values.add(properties.getProperty(key));
 		}
 		return values;
 	}
 
 	/**
 	 * Return a sorted <code>List</code> of keys from <code>properties</code> that end with <code>suffix</code>.
 	 */
 	public static final List<String> getEndsWithKeys(Properties properties, String suffix) {
 		List<String> keys = getSortedKeys(properties);
 		List<String> matches = new ArrayList<String>();
 		for (String key : keys) {
 			if (StringUtils.endsWith(key, suffix)) {
 				matches.add(key);
 			}
 		}
 		return matches;
 	}
 
 	/**
 	 * Alter the <code>properties</code> passed in to contain only the desired property values. <code>includes</code> and <code>excludes</code> are comma separated values.
 	 */
 	public static final void trim(Properties properties, String includesCSV, String excludesCSV) {
 		List<String> includes = CollectionUtils.getTrimmedListFromCSV(includesCSV);
 		List<String> excludes = CollectionUtils.getTrimmedListFromCSV(excludesCSV);
 		trim(properties, includes, excludes);
 	}
 
 	/**
 	 * Alter the <code>properties</code> passed in to contain only the desired property values.
 	 */
 	public static final void trim(Properties properties, List<String> includes, List<String> excludes) {
 		List<String> keys = getSortedKeys(properties);
 		for (String key : keys) {
 			if (!include(key, includes, excludes)) {
 				logger.debug("Removing [{}]", key);
 				properties.remove(key);
 			}
 		}
 	}
 
 	/**
 	 * Return true if <code>value</code> should be included, false otherwise.<br>
 	 * If <code>excludes</code> is not empty and matches <code>value</code> return false.<br>
 	 * If <code>value</code> has not been explicitly excluded, check the <code>includes</code> list.<br>
 	 * If <code>includes</code> is empty return true.<br>
 	 * If <code>includes</code> is not empty, return true if, and only if, <code>value</code> matches a pattern from the <code>includes</code> list.<br>
 	 * A single wildcard <code>*</code> is supported for <code>includes</code> and <code>excludes</code>.<br>
 	 */
 	public static final boolean include(String value, List<String> includes, List<String> excludes) {
 		if (isSingleWildcardMatch(value, excludes)) {
 			// No point incurring the overhead of matching an include pattern
 			return false;
 		} else {
 			// If includes is empty always return true
 			return CollectionUtils.isEmpty(includes) || isSingleWildcardMatch(value, includes);
 		}
 	}
 
 	public static final boolean isSingleWildcardMatch(String s, List<String> patterns) {
 		for (String pattern : CollectionUtils.toEmptyList(patterns)) {
 			if (isSingleWildcardMatch(s, pattern)) {
 				return true;
 			}
 		}
 		return false;
 	}
 
 	/**
 	 * Match {@code value} against {@code pattern} where {@code pattern} can optionally contain a single wildcard {@code *}. If both are {@code null} return {@code true}. If one of
 	 * {@code value} or {@code pattern} is {@code null} but the other isn't, return {@code false}. Any {@code pattern} containing more than a single wildcard throws
 	 * {@code IllegalArgumentException}.
 	 * 
 	 * <pre>
 	 * PropertyUtils.isSingleWildcardMatch(null, null)          = true
 	 * PropertyUtils.isSingleWildcardMatch(null, *)             = false
 	 * PropertyUtils.isSingleWildcardMatch(*, null)             = false
 	 * PropertyUtils.isSingleWildcardMatch(*, "*")              = true
 	 * PropertyUtils.isSingleWildcardMatch("abcdef", "bcd")     = false
 	 * PropertyUtils.isSingleWildcardMatch("abcdef", "*def")    = true
 	 * PropertyUtils.isSingleWildcardMatch("abcdef", "abc*")    = true
 	 * PropertyUtils.isSingleWildcardMatch("abcdef", "ab*ef")   = true
 	 * PropertyUtils.isSingleWildcardMatch("abcdef", "abc*def") = true
 	 * PropertyUtils.isSingleWildcardMatch(*, "**")             = IllegalArgumentException
 	 * </pre>
 	 */
 	public static final boolean isSingleWildcardMatch(String value, String pattern) {
 		if (value == null && pattern == null) {
 			// both are null
 			return true;
 		} else if (value != null && pattern == null || value == null && pattern != null) {
 			// One is null, but not the other
 			return false;
 		} else if (pattern.equals(Constants.WILDCARD)) {
 			// neither one is null and pattern is the wildcard. Value is irrelevant
 			return true;
 		} else if (StringUtils.countMatches(pattern, Constants.WILDCARD) > 1) {
 			// More than one wildcard in the pattern is not supported
 			throw new IllegalArgumentException("Pattern [" + pattern + "] is not supported.  Only one wildcard is allowed in the pattern");
 		} else if (!StringUtils.contains(pattern, Constants.WILDCARD)) {
 			// Neither one is null and there is no wildcard in the pattern. They must match exactly
 			return StringUtils.equals(value, pattern);
 		} else {
 			// The pattern contains 1 (and only 1) wildcard
 			// Make sure value starts with the characters to the left of the wildcard
 			// and ends with the characters to the right of the wildcard
 			int pos = StringUtils.indexOf(pattern, Constants.WILDCARD);
 			int suffixPos = pos + Constants.WILDCARD.length();
 			boolean nullPrefix = pos == 0;
 			boolean nullSuffix = suffixPos >= pattern.length();
 			String prefix = nullPrefix ? null : StringUtils.substring(pattern, 0, pos);
 			String suffix = nullSuffix ? null : StringUtils.substring(pattern, suffixPos);
 			boolean prefixMatch = nullPrefix || StringUtils.startsWith(value, prefix);
 			boolean suffixMatch = nullSuffix || StringUtils.endsWith(value, suffix);
 			return prefixMatch && suffixMatch;
 		}
 	}
 
 	/**
 	 * Return property keys that should be included as a sorted list.
 	 */
 	public static final Properties getProperties(Properties properties, String include, String exclude) {
 		List<String> keys = getSortedKeys(properties, include, exclude);
 		Properties newProperties = new Properties();
 		for (String key : keys) {
 			String value = properties.getProperty(key);
 			newProperties.setProperty(key, value);
 		}
 		return newProperties;
 	}
 
 	/**
 	 * Return property keys that should be included as a sorted list.
 	 */
 	public static final List<String> getSortedKeys(Properties properties, String include, String exclude) {
 		return getSortedKeys(properties, CollectionUtils.toEmptyList(include), CollectionUtils.toEmptyList(exclude));
 	}
 
 	/**
 	 * Return property keys that should be included as a sorted list.
 	 */
 	public static final List<String> getSortedKeys(Properties properties, List<String> includes, List<String> excludes) {
 		List<String> keys = getSortedKeys(properties);
 		List<String> includedKeys = new ArrayList<String>();
 		for (String key : keys) {
 			if (include(key, includes, excludes)) {
 				includedKeys.add(key);
 			}
 		}
 		return includedKeys;
 	}
 
 	/**
 	 * Return a sorted <code>List</code> of keys from <code>properties</code> that start with <code>prefix</code>
 	 */
 	public static final List<String> getStartsWithKeys(Properties properties, String prefix) {
 		List<String> keys = getSortedKeys(properties);
 		List<String> matches = new ArrayList<String>();
 		for (String key : keys) {
 			if (StringUtils.startsWith(key, prefix)) {
 				matches.add(key);
 			}
 		}
 		return matches;
 	}
 
 	/**
 	 * Return the property keys as a sorted list.
 	 */
 	public static final List<String> getSortedKeys(Properties properties) {
 		List<String> keys = new ArrayList<String>(properties.stringPropertyNames());
 		Collections.sort(keys);
 		return keys;
 	}
 
 	public static final String toString(Properties properties) {
 		List<String> keys = getSortedKeys(properties);
 		StringBuilder sb = new StringBuilder();
 		for (String key : keys) {
 			String value = Str.flatten(properties.getProperty(key));
 			sb.append(key + "=" + value + "\n");
 		}
 		return sb.toString();
 	}
 
 	public static final void info(Properties properties) {
 		properties = toEmpty(properties);
 		logger.info("--- Displaying {} properties ---\n\n{}", properties.size(), toString(properties));
 	}
 
 	public static final void debug(Properties properties) {
 		properties = toEmpty(properties);
 		logger.debug("--- Displaying {} properties ---\n\n{}", properties.size(), toString(properties));
 	}
 
 	/**
 	 * Store the properties to the indicated file using the platform default encoding.
 	 */
 	public static final void store(Properties properties, File file) {
 		store(properties, file, null);
 	}
 
 	/**
 	 * Store the properties to the indicated file using the indicated encoding.
 	 */
 	public static final void store(Properties properties, File file, String encoding) {
 		store(properties, file, encoding, null);
 	}
 
 	/**
 	 * Store the properties to the indicated file using the indicated encoding with the indicated comment appearing at the top of the file.
 	 */
 	public static final void store(Properties properties, File file, String encoding, String comment) {
 		OutputStream out = null;
 		Writer writer = null;
 		try {
 			out = FileUtils.openOutputStream(file);
 			String path = file.getCanonicalPath();
 			boolean xml = isXml(path);
 			Properties sorted = getSortedProperties(properties);
 			comment = getComment(encoding, comment, xml);
 			if (xml) {
 				logger.info("Storing XML properties - [{}] encoding={}", path, StringUtils.defaultIfBlank(encoding, DEFAULT_ENCODING));
 				if (encoding == null) {
 					sorted.storeToXML(out, comment);
 				} else {
 					sorted.storeToXML(out, comment, encoding);
 				}
 			} else {
 				writer = LocationUtils.getWriter(out, encoding);
 				logger.info("Storing properties - [{}] encoding={}", path, StringUtils.defaultIfBlank(encoding, DEFAULT_ENCODING));
 				sorted.store(writer, comment);
 			}
 		} catch (IOException e) {
 			throw new IllegalStateException("Unexpected IO error", e);
 		} finally {
 			IOUtils.closeQuietly(writer);
 			IOUtils.closeQuietly(out);
 		}
 	}
 
 	/**
 	 * Return a new properties object containing the properties from <code>getEnvAsProperties()</code> and <code>System.getProperties()</code>. Properties from
 	 * <code>System.getProperties()</code> override properties from <code>getEnvAsProperties</code> if there are duplicates.
 	 */
 	public static final Properties getGlobalProperties() {
 		return getProperties(Constants.DEFAULT_GLOBAL_PROPERTIES_MODE);
 	}
 
 	/**
 	 * Return a new properties object containing the properties passed in, plus any properties returned by <code>getEnvAsProperties()</code> and <code>System.getProperties()</code>
 	 * . Properties from <code>getEnvAsProperties()</code> override <code>properties</code> and properties from <code>System.getProperties()</code> override everything.
 	 */
 	public static final Properties getGlobalProperties(Properties properties) {
 		return getProperties(properties, Constants.DEFAULT_GLOBAL_PROPERTIES_MODE);
 	}
 
 	/**
 	 * Return a new properties object containing the properties passed in, plus any global properties as requested. If <code>mode</code> is <code>NONE</code> the new properties are
 	 * a duplicate of the properties passed in. If <code>mode</code> is <code>ENVIRONMENT</code> the new properties contain the original properties plus any properties returned by
 	 * <code>getEnvProperties()</code>. If <code>mode</code> is <code>SYSTEM</code> the new properties contain the original properties plus <code>System.getProperties()</code>. If
 	 * <code>mode</code> is <code>BOTH</code> the new properties contain the original properties plus <code>getEnvProperties()</code> and <code>System.getProperties()</code>.
 	 */
 	public static final Properties getProperties(Properties properties, GlobalPropertiesMode mode) {
 		Properties newProperties = duplicate(properties);
 		List<PropertyProcessor> modifiers = getPropertyProcessors(mode);
 		for (PropertyProcessor modifier : modifiers) {
 			modifier.process(newProperties);
 		}
 		return newProperties;
 	}
 
 	/**
 	 * Return a new properties object containing global properties as requested. If <code>mode</code> is <code>NONE</code> the new properties are empty. If <code>mode</code> is
 	 * <code>ENVIRONMENT</code> the new properties contain the properties returned by <code>getEnvProperties()</code>. If <code>mode</code> is <code>SYSTEM</code> the new
 	 * properties contain <code>System.getProperties()</code>. If <code>mode</code> is <code>BOTH</code> the new properties contain <code>getEnvProperties</code> plus
 	 * <code>System.getProperties()</code> with system properties overriding environment variables if the same case sensitive property key is supplied in both places.
 	 */
 	public static final Properties getProperties(GlobalPropertiesMode mode) {
 		return getProperties(new Properties(), mode);
 	}
 
 	/**
 	 * Search global properties to find a value for <code>key</code> according to the mode passed in.
 	 */
 	public static final String getProperty(String key, GlobalPropertiesMode mode) {
 		return getProperty(key, new Properties(), mode);
 	}
 
 	/**
 	 * Search <code>properties</code> plus global properties to find a value for <code>key</code> according to the mode passed in. If the property is present in both, the value
 	 * from the global properties is returned.
 	 */
 	public static final String getProperty(String key, Properties properties, GlobalPropertiesMode mode) {
 		return getProperties(properties, mode).getProperty(key);
 	}
 
 	/**
 	 * Return modifiers that add environment variables, system properties, or both, according to the mode passed in.
 	 */
 	public static final List<PropertyProcessor> getPropertyProcessors(GlobalPropertiesMode mode) {
 		List<PropertyProcessor> processors = new ArrayList<PropertyProcessor>();
 		switch (mode) {
 		case NONE:
 			return processors;
 		case ENVIRONMENT:
 			processors.add(new AddPropertiesProcessor(getEnvAsProperties()));
 			return processors;
 		case SYSTEM:
 			processors.add(new AddPropertiesProcessor(System.getProperties()));
 			return processors;
 		case BOTH:
 			processors.add(new AddPropertiesProcessor(getEnvAsProperties()));
 			processors.add(new AddPropertiesProcessor(System.getProperties()));
 			return processors;
 		default:
 			throw new IllegalStateException(mode + " is unknown");
 		}
 	}
 
 	/**
 	 * Convert the <code>Map</code> to a <code>Properties</code> object.
 	 */
 	public static final Properties convert(Map<String, String> map) {
 		Properties props = new Properties();
 		for (String key : map.keySet()) {
 			String value = map.get(key);
 			props.setProperty(key, value);
 		}
 		return props;
 	}
 
 	/**
 	 * Return a new properties object that duplicates the properties passed in.
 	 */
 	public static final Properties duplicate(Properties properties) {
 		Properties newProperties = new Properties();
 		newProperties.putAll(properties);
 		return newProperties;
 	}
 
 	/**
 	 * Return a new properties object containing environment variables as properties prefixed with <code>env</code>
 	 */
 	public static Properties getEnvAsProperties() {
 		return getEnvAsProperties(ENV_PREFIX);
 	}
 
 	/**
 	 * Return a new properties object containing environment variables as properties prefixed with <code>prefix</code>
 	 */
 	public static Properties getEnvAsProperties(String prefix) {
 		Properties properties = convert(System.getenv());
 		return getPrefixedProperties(properties, prefix);
 	}
 
 	/**
 	 * Return true if, and only if, location ends with <code>.xml</code> (case insensitive).
 	 */
 	public static final boolean isXml(String location) {
 		return StringUtils.endsWithIgnoreCase(location, XML_EXTENSION);
 	}
 
 	/**
 	 * Return a new <code>Properties</code> object loaded from <code>file</code>.
 	 */
 	public static final Properties load(File file) {
 		return load(file, null);
 	}
 
 	/**
 	 * Return a new <code>Properties</code> object loaded from <code>file</code> using the given encoding.
 	 */
 	public static final Properties load(File file, String encoding) {
 		String location = LocationUtils.getCanonicalPath(file);
 		return load(location, encoding);
 	}
 
 	/**
 	 * Return a new <code>Properties</code> object loaded from <code>location</code>.
 	 */
 	public static final Properties load(String location) {
 		return load(location, null);
 	}
 
 	/**
 	 * Return a new <code>Properties</code> object loaded from <code>location</code> using <code>encoding</code>.
 	 */
 	public static final Properties load(String location, String encoding) {
 		InputStream in = null;
 		Reader reader = null;
 		try {
 			Properties properties = new Properties();
 			boolean xml = isXml(location);
 			location = getCanonicalLocation(location);
 			if (xml) {
 				in = LocationUtils.getInputStream(location);
 				logger.info("Loading XML properties - [{}]", location);
 				properties.loadFromXML(in);
 			} else {
 				logger.info("Loading properties - [{}] encoding={}", location, StringUtils.defaultIfBlank(encoding, DEFAULT_ENCODING));
 				reader = LocationUtils.getBufferedReader(location, encoding);
 				properties.load(reader);
 			}
 			return properties;
 		} catch (IOException e) {
 			throw new IllegalStateException("Unexpected IO error", e);
 		} finally {
 			IOUtils.closeQuietly(in);
 			IOUtils.closeQuietly(reader);
 		}
 	}
 
 	protected static String getCanonicalLocation(String location) {
 		if (LocationUtils.isExistingFile(location)) {
 			return LocationUtils.getCanonicalPath(new File(location));
 		} else {
 			return location;
 		}
 	}
 
 	/**
 	 * Return a new <code>Properties</code> object containing properties prefixed with <code>prefix</code>. If <code>prefix</code> is blank, the new properties object duplicates
 	 * the properties passed in.
 	 */
 	public static final Properties getPrefixedProperties(Properties properties, String prefix) {
 		if (StringUtils.isBlank(prefix)) {
 			return duplicate(properties);
 		}
 		Properties newProperties = new Properties();
 		for (String key : properties.stringPropertyNames()) {
 			String value = properties.getProperty(key);
 			String newKey = StringUtils.startsWith(key, prefix + ".") ? key : prefix + "." + key;
 			newProperties.setProperty(newKey, value);
 		}
 		return newProperties;
 	}
 
 	/**
 	 * Return a new properties object where the keys have been converted to upper case and periods have been replaced with an underscore.
 	 */
 	public static final Properties reformatKeysAsEnvVars(Properties properties) {
 		Properties newProperties = new Properties();
 		for (String key : properties.stringPropertyNames()) {
 			String value = properties.getProperty(key);
 			String newKey = StringUtils.upperCase(StringUtils.replace(key, ".", "-"));
 			newProperties.setProperty(newKey, value);
 		}
 		return newProperties;
 	}
 
 	/**
 	 * Before setting the newValue, check to see if there is a conflict with an existing value. If there is no existing value, add the property. If there is a conflict, check
 	 * <code>propertyOverwriteMode</code> to make sure we have permission to override the value.
 	 */
 	public static final void addOrOverrideProperty(Properties properties, String key, String newValue, Mode propertyOverwriteMode) {
 		String oldValue = properties.getProperty(key);
 		if (StringUtils.equals(newValue, oldValue)) {
 			// Nothing to do! New value is the same as old value.
 			return;
 		}
 		boolean overwrite = !StringUtils.isBlank(oldValue);
 
 		// TODO Yuck! Do something smarter here
 		String logNewValue = newValue;
 		String logOldValue = oldValue;
 		if (obscure(key)) {
 			logNewValue = "PROTECTED";
 			logOldValue = "PROTECTED";
 		}
 
 		if (overwrite) {
 			// This property already has a value, and it is different from the new value
 			// Check to make sure we are allowed to override the old value before doing so
 			Object[] args = new Object[] { key, Str.flatten(logNewValue), Str.flatten(logOldValue) };
 			ModeUtils.validate(propertyOverwriteMode, "Overriding [{}={}] was [{}]", args, "Override of existing property [" + key + "] is not allowed.");
 		} else {
 			// There is no existing value for this key
 			logger.info("Adding [{}={}]", key, Str.flatten(logNewValue));
 		}
 		properties.setProperty(key, newValue);
 	}
 
 	protected static boolean obscure(String key) {
 		if (StringUtils.containsIgnoreCase(key, ".password")) {
 			return true;
 		}
 		if (StringUtils.containsIgnoreCase(key, ".secret")) {
 			return true;
 		}
 		if (StringUtils.containsIgnoreCase(key, ".private")) {
 			return true;
 		}
 		return false;
 	}
 
 	private static final String getDefaultComment(String encoding, boolean xml) {
 		if (encoding == null) {
 			if (xml) {
 				// Java defaults XML properties files to UTF-8 if no encoding is provided
 				return "encoding.default=" + DEFAULT_XML_ENCODING;
 			} else {
 				// For normal properties files the platform default encoding is used
 				return "encoding.default=" + DEFAULT_ENCODING;
 			}
 		} else {
 			return "encoding.specified=" + encoding;
 		}
 	}
 
 	private static final String getComment(String encoding, String comment, boolean xml) {
 		if (StringUtils.isBlank(comment)) {
 			return getDefaultComment(encoding, xml);
 		} else {
 			return comment + "\n#" + getDefaultComment(encoding, xml);
 		}
 	}
 
 	/**
 	 * This is private because <code>SortedProperties</code> does not fully honor the contract for <code>Properties</code>
 	 */
 	private static final SortedProperties getSortedProperties(Properties properties) {
 		SortedProperties sp = new PropertyUtils().new SortedProperties();
 		sp.putAll(properties);
 		return sp;
 	}
 
 	/**
 	 * This is private since it does not honor the full contract for <code>Properties</code>. <code>PropertyUtils</code> uses it internally to store properties in sorted order.
 	 */
 	private class SortedProperties extends Properties {
 
 		private static final long serialVersionUID = 1330825236411537386L;
 
 		/**
 		 * <code>Properties.storeToXML()</code> uses <code>keySet()</code>
 		 */
 		@Override
 		public Set<Object> keySet() {
 			return Collections.unmodifiableSet(new TreeSet<Object>(super.keySet()));
 		}
 
 		/**
 		 * <code>Properties.store()</code> uses <code>keys()</code>
 		 */
 		@Override
 		public synchronized Enumeration<Object> keys() {
 			return Collections.enumeration(new TreeSet<Object>(super.keySet()));
 		}
 	}
 
 	/**
 	 * Set properties in the given Properties to CSV versions of the lists in the ComparisonResults
 	 * 
 	 * @param properties
 	 *            the Properties to populate
 	 * @param listComparison
 	 *            the ComparisonResults to use for data
 	 * @param propertyNames
 	 *            the list of property keys to set. Exactly 3 names are required, and the assumed order is: index 0: key for the ADDED list index 1: key for the SAME list index 2:
 	 *            key for the DELETED list
 	 */
 	public static final void addListComparisonProperties(Properties properties, ComparisonResults listComparison, List<String> propertyNames) {
 		// make sure that there are three names in the list of property names
 		Assert.isTrue(propertyNames.size() == 3);
 
 		properties.setProperty(propertyNames.get(0), CollectionUtils.getCSV(listComparison.getAdded()));
 		properties.setProperty(propertyNames.get(1), CollectionUtils.getCSV(listComparison.getSame()));
 		properties.setProperty(propertyNames.get(2), CollectionUtils.getCSV(listComparison.getDeleted()));
 	}
 
 }