HHH-2761 : null and empty string consistency in PropertiesHelper (javadocs)

git-svn-id: https://svn.jboss.org/repos/hibernate/core/trunk@12889 1b8cb986-b30d-0410-93ca-fae66ebed9b2
This commit is contained in:
Steve Ebersole 2007-08-03 03:57:59 +00:00
parent e9065e13a0
commit 6472dac702
1 changed files with 127 additions and 7 deletions

View File

@ -7,16 +7,48 @@ import java.util.Properties;
import java.util.StringTokenizer; import java.util.StringTokenizer;
import java.util.Iterator; import java.util.Iterator;
/**
* Collection of helper methods for dealing with {@link java.util.Properties}
* objects.
*
* @author Gavin King
* @author Steve Ebersole
*/
public final class PropertiesHelper { public final class PropertiesHelper {
private static final String PLACEHOLDER_START = "${"; private static final String PLACEHOLDER_START = "${";
/**
* Disallow instantiation
*/
private PropertiesHelper() {
}
/**
* Get a property value as a string.
*
* @see #extractPropertyValue(String, java.util.Properties)
*
* @param propertyName The name of the property for which to retrieve value
* @param properties The properties object
* @param defaultValue The default property value to use.
* @return The property value; may be null.
*/
public static String getString(String propertyName, Properties properties, String defaultValue) { public static String getString(String propertyName, Properties properties, String defaultValue) {
String value = extractPropertyValue( propertyName, properties ); String value = extractPropertyValue( propertyName, properties );
return value == null ? defaultValue : value; return value == null ? defaultValue : value;
} }
private static String extractPropertyValue(String propertyName, Properties properties) { /**
* Extract a property value by name from the given properties object.
* <p/>
* Both <tt>null</tt> and <tt>empty string</tt> are viewed as the same, and return null.
*
* @param propertyName The name of the property for which to extract value
* @param properties The properties object
* @return The property value; may be null.
*/
public static String extractPropertyValue(String propertyName, Properties properties) {
String value = properties.getProperty( propertyName ); String value = properties.getProperty( propertyName );
if ( value == null ) { if ( value == null ) {
return null; return null;
@ -28,25 +60,85 @@ public final class PropertiesHelper {
return value; return value;
} }
public static boolean getBoolean(String property, Properties properties) { /**
return getBoolean( property, properties, false ); * Get a property value as a boolean. Shorthand for calling
* {@link #getBoolean(String, java.util.Properties, boolean)} with <tt>false</tt>
* as the default value.
*
* @param propertyName The name of the property for which to retrieve value
* @param properties The properties object
* @return The property value.
*/
public static boolean getBoolean(String propertyName, Properties properties) {
return getBoolean( propertyName, properties, false );
} }
/**
* Get a property value as a boolean.
* <p/>
* First, the string value is extracted, and then {@link Boolean#valueOf(String)} is
* used to determine the correct boolean value.
*
* @see #extractPropertyValue(String, java.util.Properties)
*
* @param propertyName The name of the property for which to retrieve value
* @param properties The properties object
* @param defaultValue The default property value to use.
* @return The property value.
*/
public static boolean getBoolean(String propertyName, Properties properties, boolean defaultValue) { public static boolean getBoolean(String propertyName, Properties properties, boolean defaultValue) {
String value = extractPropertyValue( propertyName, properties ); String value = extractPropertyValue( propertyName, properties );
return value == null ? defaultValue : Boolean.valueOf( value ).booleanValue(); return value == null ? defaultValue : Boolean.valueOf( value ).booleanValue();
} }
/**
* Get a property value as an int.
* <p/>
* First, the string value is extracted, and then {@link Integer#parseInt(String)} is
* used to determine the correct int value for any non-null property values.
*
* @see #extractPropertyValue(String, java.util.Properties)
*
* @param propertyName The name of the property for which to retrieve value
* @param properties The properties object
* @param defaultValue The default property value to use.
* @return The property value.
*/
public static int getInt(String propertyName, Properties properties, int defaultValue) { public static int getInt(String propertyName, Properties properties, int defaultValue) {
String value = extractPropertyValue( propertyName, properties ); String value = extractPropertyValue( propertyName, properties );
return value == null ? defaultValue : Integer.parseInt( value ); return value == null ? defaultValue : Integer.parseInt( value );
} }
/**
* Get a property value as an Integer.
* <p/>
* First, the string value is extracted, and then {@link Integer#valueOf(String)} is
* used to determine the correct boolean value for any non-null property values.
*
* @see #extractPropertyValue(String, java.util.Properties)
*
* @param propertyName The name of the property for which to retrieve value
* @param properties The properties object
* @return The property value; may be null.
*/
public static Integer getInteger(String propertyName, Properties properties) { public static Integer getInteger(String propertyName, Properties properties) {
String value = extractPropertyValue( propertyName, properties ); String value = extractPropertyValue( propertyName, properties );
return value == null ? null : Integer.valueOf( value ); return value == null ? null : Integer.valueOf( value );
} }
/**
* Constructs a map from a property value.
* <p/>
* The exact behavior here is largely dependant upon what is passed in as
* the delimiter.
*
* @see #extractPropertyValue(String, java.util.Properties)
*
* @param propertyName The name of the property for which to retrieve value
* @param delim The string defining tokens used as both entry and key/value delimiters.
* @param properties The properties object
* @return The resulting map; never null, though perhaps empty.
*/
public static Map toMap(String propertyName, String delim, Properties properties) { public static Map toMap(String propertyName, String delim, Properties properties) {
Map map = new HashMap(); Map map = new HashMap();
String value = extractPropertyValue( propertyName, properties ); String value = extractPropertyValue( propertyName, properties );
@ -59,11 +151,32 @@ public final class PropertiesHelper {
return map; return map;
} }
/**
* Get a property value as a string array.
*
* @see #extractPropertyValue(String, java.util.Properties)
* @see #toStringArray(String, String)
*
* @param propertyName The name of the property for which to retrieve value
* @param delim The delimiter used to separate individual array elements.
* @param properties The properties object
* @return The array; never null, though may be empty.
*/
public static String[] toStringArray(String propertyName, String delim, Properties properties) { public static String[] toStringArray(String propertyName, String delim, Properties properties) {
return toStringArray( extractPropertyValue( propertyName, properties ), delim ); return toStringArray( extractPropertyValue( propertyName, properties ), delim );
} }
/**
* Convert a string to an array of strings. The assumption is that
* the individual array elements are delimited in the source stringForm
* param by the delim param.
*
* @param stringForm The string form of the string array.
* @param delim The delimiter used to separate individual array elements.
* @return The array; never null, though may be empty.
*/
public static String[] toStringArray(String stringForm, String delim) { public static String[] toStringArray(String stringForm, String delim) {
// todo : move to StringHelper?
if ( stringForm != null ) { if ( stringForm != null ) {
return StringHelper.split( delim, stringForm ); return StringHelper.split( delim, stringForm );
} }
@ -87,6 +200,11 @@ public final class PropertiesHelper {
return clone; return clone;
} }
/**
* Handles interpolation processing for all entries in a properties object.
*
* @param properties The properties object.
*/
public static void resolvePlaceHolders(Properties properties) { public static void resolvePlaceHolders(Properties properties) {
Iterator itr = properties.entrySet().iterator(); Iterator itr = properties.entrySet().iterator();
while ( itr.hasNext() ) { while ( itr.hasNext() ) {
@ -106,6 +224,12 @@ public final class PropertiesHelper {
} }
} }
/**
* Handles interpolation processing for a single property.
*
* @param property The property value to be processed for interpolation.
* @return The (possibly) interpolated property value.
*/
public static String resolvePlaceHolder(String property) { public static String resolvePlaceHolder(String property) {
if ( property.indexOf( PLACEHOLDER_START ) < 0 ) { if ( property.indexOf( PLACEHOLDER_START ) < 0 ) {
return property; return property;
@ -150,8 +274,4 @@ public final class PropertiesHelper {
return null; return null;
} }
} }
private PropertiesHelper() {
}
} }