0.10/commons/src/main/java/org/apache/oodt/commons/util/Utility.java - oodt - Git at Google

 // Licensed to the Apache Software Foundation (ASF) under one or more contributor
 // license agreements.  See the NOTICE.txt file distributed with this work for
 // additional information regarding copyright ownership.  The ASF licenses this
 // file to you 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.apache.oodt.commons.util;

 import java.io.BufferedInputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Properties;
 import java.util.StringTokenizer;

 /** Miscellaneous utilities.
  *
  * This class contains various miscellaneous functions as static methods.
  *
  * @author Kelly
  */
 public class Utility {
 	/** Load properties from a resource.
 	 *
 	 * This loads properties from the given resource (relative to the given class)
 	 * into the given properties object.  If any error occurs, this method prints a
 	 * message to stderr but otherwise takes no special action.
 	 *
 	 * <p>You typically use this to merge properties for your application into the
 	 * System properties by calling this method as follows:
 	 * <pre>Utility.loadProperties(System.getProperties(), MyClass.class,
 	 * "MyClass.properties");</pre> This adds the properties from the file
 	 * <code>MyClass.properties</code> (which must exist in the same directory as the
 	 * file <code>MyClass.class</code>, whether in the filesystem or in a jar) into
 	 * the system properties.  You can then fetch these properties from anywhere in
 	 * your program with <code>System.getProperty(String)</code>,
 	 * <code>Integer.getInteger</code>, etc.
 	 *
 	 * <p>You can also use the method to load properties into a newly created
 	 * properties object that you provide.  This keeps your properties separate, but
 	 * then you have to pass a properties object all over the place, and you can't
 	 * take advantage of non-String properties through methods like
 	 * <code>Long#getLong(String)</code>, etc.
 	 *
 	 * @param props The properties object to load.
 	 * @param clazz The class used to locate the resource.
 	 * @param resourceName The name of the resource.
 	 */
 	public static void loadProperties(Properties props, final Class clazz, final String resourceName) {
 		BufferedInputStream in = null;
 		try {
 			in = new BufferedInputStream(clazz.getResourceAsStream(resourceName));
 			props.load(in);
 		} catch (IOException ex) {
 			System.err.println("I/O exception while loading \"" + resourceName + "\": " + ex.getMessage());
 		} finally {
 			if (in != null) try {
 				in.close();
 			} catch (IOException ignore) {}
 		}
 	}

 	/** Parse a list.
 	 *
 	 * This yields an iterator created from a list where commas (and optional leading
 	 * and trailing whitespace) separate each element.  Each element will occur only
 	 * once in the iterator regardless of how many times it appeared in the string.
 	 *
 	 * @param list The list to parse.
 	 * @return The iterator over unique elements in the <var>list</var>.
 	 */
 	public static Iterator parseCommaList(final String list) {
 		if (list == null) return new Iterator() {
 			public boolean hasNext() {
 				return false;
 			}
 			public Object next() {
 				throw new java.util.NoSuchElementException("There weren't ANY elements in this iterator, ever");
 			}
 			public void remove() {
 				throw new UnsupportedOperationException("Can't remove elements from this iterator");
 			}
 		};
 		HashSet set = new HashSet();
 		StringTokenizer tokens = new StringTokenizer(list, ",");
 		while (tokens.hasMoreTokens())
 			set.add(tokens.nextToken().trim());
 		return set.iterator();
 	}

 	/** Asynchronously redirect an input stream onto an output stream.
 	 *
 	 * The output stream is never closed.
 	 *
 	 * @param in Input stream to redirect.
 	 * @param out Where to redirect <var>in</var>.
 	 */
 	public static void redirect(final InputStream in, final OutputStream out) {
 		new Thread() {
 			public void run() {
 				try {
 					byte[] buf = new byte[1024];
 					for (;;) {
 						int numRead = in.read(buf);
 						if (numRead == -1) {
 							in.close();
 							break;
 						}
 						out.write(buf, 0, numRead);
 					}
 				} catch (IOException ex) {
 					try {
 						in.close();
 					} catch (IOException ignore) {}
 				}
 			}
 		}.start();
 	}

 	/** Log statistics on memory to stderr.
 	 *
 	 * @param msg Text to include in log.
 	 */
 	public static void logMemoryStats(String msg) {
 		Runtime rt = Runtime.getRuntime();
 		System.err.println(msg + ": total=" + (rt.totalMemory() / 1024) + "KB, free=" + (rt.freeMemory() / 1024) + "KB");
 	}

 	/** Check string s is numeric.  Numeric strings include 5.7, -3.9, 14.981E16, etc.
          *
          * @param s Text to be checked.
 	 * @return True is <var>s</var> is a numeric string.
          */
 	public static boolean isNumeric(String s) {
                 try {
                         Double.parseDouble(s);
                 } catch (NumberFormatException ex) {
                          return false;
                 }
                 return true;
         }

 	/**
 	 * Delete a file or directory.  If <var>file</var> references a directory, it
 	 * recursively deletes all the directory tree.
 	 *
 	 * @param file File, directory, or other filesystem artifact to delete.
 	 * @return True if <var>file</var> was deleted, false otherwise.
 	 */
 	public static boolean delete(File file) {
 		if (file.isDirectory()) {
 			File[] entries = file.listFiles();
 			for (int i = 0; i < entries.length; ++i)
 				if (!delete(entries[i]))
 					return false;
 		}
 		return file.delete();
 	}

    /**
     * This method will escape any single quotes found in the input string
     * and return the escaped string. This will ready the string for
     * insertion into a database. The single quote is escaped by inserting
     * an additional single quote in front of it in the string. If some
     * considerate developer has already escaped the single quotes in the
     * input string, this method will essentially do nothing.
     *
     * @param inputString The string to be escaped.
     * @return The escaped string.
     */
    public static String escapeSingleQuote(String inputString) {

       int index = inputString.indexOf('\'');
       if (index == -1) {
          return (inputString);
       }

       String outputString = inputString;
       while (index != -1) {

          // If the single quote is the last character in the string or
          // the next character is not another single quote, insert a
          // single quote in front of the current single quote.
          if ((index == (outputString.length() - 1)) || (outputString.charAt(index + 1) != '\'')) {
             outputString = outputString.substring(0, index) + "'" + outputString.substring(index);
          }

          // If we are not at the end of the string, check for another
          // single quote.
          if ((index + 2) <= (outputString.length() - 1)) {
             index = outputString.indexOf('\'', index + 2);
          }
          else {
             index = -1;
          }
       }
       return (outputString);
    }
 }
	// Licensed to the Apache Software Foundation (ASF) under one or more contributor
	// license agreements. See the NOTICE.txt file distributed with this work for
	// additional information regarding copyright ownership. The ASF licenses this
	// file to you 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.apache.oodt.commons.util;

	import java.io.BufferedInputStream;
	import java.io.File;
	import java.io.IOException;
	import java.io.InputStream;
	import java.io.OutputStream;
	import java.util.HashSet;
	import java.util.Iterator;
	import java.util.Properties;
	import java.util.StringTokenizer;

	/** Miscellaneous utilities.
	*
	* This class contains various miscellaneous functions as static methods.
	*
	* @author Kelly
	*/
	public class Utility {
	/** Load properties from a resource.
	*
	* This loads properties from the given resource (relative to the given class)
	* into the given properties object. If any error occurs, this method prints a
	* message to stderr but otherwise takes no special action.
	*
	* <p>You typically use this to merge properties for your application into the
	* System properties by calling this method as follows:
	* <pre>Utility.loadProperties(System.getProperties(), MyClass.class,
	* "MyClass.properties");</pre> This adds the properties from the file
	* <code>MyClass.properties</code> (which must exist in the same directory as the
	* file <code>MyClass.class</code>, whether in the filesystem or in a jar) into
	* the system properties. You can then fetch these properties from anywhere in
	* your program with <code>System.getProperty(String)</code>,
	* <code>Integer.getInteger</code>, etc.
	*
	* <p>You can also use the method to load properties into a newly created
	* properties object that you provide. This keeps your properties separate, but
	* then you have to pass a properties object all over the place, and you can't
	* take advantage of non-String properties through methods like
	* <code>Long#getLong(String)</code>, etc.
	*
	* @param props The properties object to load.
	* @param clazz The class used to locate the resource.
	* @param resourceName The name of the resource.
	*/
	public static void loadProperties(Properties props, final Class clazz, final String resourceName) {
	BufferedInputStream in = null;
	try {
	in = new BufferedInputStream(clazz.getResourceAsStream(resourceName));
	props.load(in);
	} catch (IOException ex) {
	System.err.println("I/O exception while loading \"" + resourceName + "\": " + ex.getMessage());
	} finally {
	if (in != null) try {
	in.close();
	} catch (IOException ignore) {}
	}
	}

	/** Parse a list.
	*
	* This yields an iterator created from a list where commas (and optional leading
	* and trailing whitespace) separate each element. Each element will occur only
	* once in the iterator regardless of how many times it appeared in the string.
	*
	* @param list The list to parse.
	* @return The iterator over unique elements in the <var>list</var>.
	*/
	public static Iterator parseCommaList(final String list) {
	if (list == null) return new Iterator() {
	public boolean hasNext() {
	return false;
	}
	public Object next() {
	throw new java.util.NoSuchElementException("There weren't ANY elements in this iterator, ever");
	}
	public void remove() {
	throw new UnsupportedOperationException("Can't remove elements from this iterator");
	}
	};
	HashSet set = new HashSet();
	StringTokenizer tokens = new StringTokenizer(list, ",");
	while (tokens.hasMoreTokens())
	set.add(tokens.nextToken().trim());
	return set.iterator();
	}

	/** Asynchronously redirect an input stream onto an output stream.
	*
	* The output stream is never closed.
	*
	* @param in Input stream to redirect.
	* @param out Where to redirect <var>in</var>.
	*/
	public static void redirect(final InputStream in, final OutputStream out) {
	new Thread() {
	public void run() {
	try {
	byte[] buf = new byte[1024];
	for (;;) {
	int numRead = in.read(buf);
	if (numRead == -1) {
	in.close();
	break;
	}
	out.write(buf, 0, numRead);
	}
	} catch (IOException ex) {
	try {
	in.close();
	} catch (IOException ignore) {}
	}
	}
	}.start();
	}

	/** Log statistics on memory to stderr.
	*
	* @param msg Text to include in log.
	*/
	public static void logMemoryStats(String msg) {
	Runtime rt = Runtime.getRuntime();
	System.err.println(msg + ": total=" + (rt.totalMemory() / 1024) + "KB, free=" + (rt.freeMemory() / 1024) + "KB");
	}

	/** Check string s is numeric. Numeric strings include 5.7, -3.9, 14.981E16, etc.
	*
	* @param s Text to be checked.
	* @return True is <var>s</var> is a numeric string.
	*/
	public static boolean isNumeric(String s) {
	try {
	Double.parseDouble(s);
	} catch (NumberFormatException ex) {
	return false;
	}
	return true;
	}

	/**
	* Delete a file or directory. If <var>file</var> references a directory, it
	* recursively deletes all the directory tree.
	*
	* @param file File, directory, or other filesystem artifact to delete.
	* @return True if <var>file</var> was deleted, false otherwise.
	*/
	public static boolean delete(File file) {
	if (file.isDirectory()) {
	File[] entries = file.listFiles();
	for (int i = 0; i < entries.length; ++i)
	if (!delete(entries[i]))
	return false;
	}
	return file.delete();
	}

	/**
	* This method will escape any single quotes found in the input string
	* and return the escaped string. This will ready the string for
	* insertion into a database. The single quote is escaped by inserting
	* an additional single quote in front of it in the string. If some
	* considerate developer has already escaped the single quotes in the
	* input string, this method will essentially do nothing.
	*
	* @param inputString The string to be escaped.
	* @return The escaped string.
	*/
	public static String escapeSingleQuote(String inputString) {

	int index = inputString.indexOf('\'');
	if (index == -1) {
	return (inputString);
	}

	String outputString = inputString;
	while (index != -1) {

	// If the single quote is the last character in the string or
	// the next character is not another single quote, insert a
	// single quote in front of the current single quote.
	if ((index == (outputString.length() - 1)) \|\| (outputString.charAt(index + 1) != '\'')) {
	outputString = outputString.substring(0, index) + "'" + outputString.substring(index);
	}

	// If we are not at the end of the string, check for another
	// single quote.
	if ((index + 2) <= (outputString.length() - 1)) {
	index = outputString.indexOf('\'', index + 2);
	}
	else {
	index = -1;
	}
	}
	return (outputString);
	}
	}