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Java lang extensions for java6+, a supplement to , replacement of a Guava, commons-lang.
Core utilities, Collection utilities, IO utilities, Cache, Configuration library ...
package com.jn.langx.commandline.environment;
import java.io.IOException;
import java.util.Map;
import java.util.Map.Entry;
/**
* Wrapper for environment variables.
*/
public class EnvironmentUtils {
private static final DefaultProcessingEnvironment PROCESSING_ENVIRONMENT_IMPLEMENTATION;
static {
// if (OS.isFamilyOpenVms()) {
// PROCESSING_ENVIRONMENT_IMPLEMENTATION = new OpenVmsProcessingEnvironment();
// } else {
PROCESSING_ENVIRONMENT_IMPLEMENTATION = new DefaultProcessingEnvironment();
// }
}
/**
* Disable constructor.
*/
private EnvironmentUtils() {
}
/**
* Get the variable list as an array.
*
* @param environment the environment to use, may be {@code null}
* @return array of key=value assignment strings or {@code null} if and only if
* the input map was {@code null}
*/
public static String[] toStrings(final Map environment) {
if (environment == null) {
return null;
}
final String[] result = new String[environment.size()];
int i = 0;
for (final Entry entry : environment.entrySet()) {
final String key = entry.getKey() == null ? "" : entry.getKey().toString();
final String value = entry.getValue() == null ? "" : entry.getValue().toString();
result[i] = key + "=" + value;
i++;
}
return result;
}
/**
* Find the list of environment variables for this process. The returned map preserves
* the casing of a variable's name on all platforms but obeys the casing rules of the
* current platform during lookup, e.g. key names will be case-insensitive on Windows
* platforms.
*
* @return a map containing the environment variables, may be empty but never {@code null}
* @throws IOException the operation failed
*/
public static Map getProcEnvironment() throws IOException {
return PROCESSING_ENVIRONMENT_IMPLEMENTATION.getProcEnvironment();
}
/**
* Add a key/value pair to the given environment.
* If the key matches an existing key, the previous setting is replaced.
*
* @param environment the current environment
* @param keyAndValue the key/value pair
*/
public static void addVariableToEnvironment(final Map environment, final String keyAndValue) {
final String[] parsedVariable = parseEnvironmentVariable(keyAndValue);
environment.put(parsedVariable[0], parsedVariable[1]);
}
/**
* Split a key/value pair into a String[]. It is assumed
* that the ky/value pair contains a '=' character.
*
* @param keyAndValue the key/value pair
* @return a String[] containing the key and value
*/
private static String[] parseEnvironmentVariable(final String keyAndValue) {
final int index = keyAndValue.indexOf('=');
if (index == -1) {
throw new IllegalArgumentException(
"Environment variable for this platform "
+ "must contain an equals sign ('=')");
}
final String[] result = new String[2];
result[0] = keyAndValue.substring(0, index);
result[1] = keyAndValue.substring(index + 1);
return result;
}
}