/**
* <code>ExpressionFilenameParser</code> can use any expression language supported by Mule to
* construct a file name for the current message. Expressions can be xpath, xquery, ognl, mvel,
* header, function and more. For more information see
* http://www.mulesoft.org/documentation/display/MULE3USER/Using+Expressions.
*
* <p>For example an xpath expression can be defined to pull a message id out of an xml message and
* use that as the file name - <code>
* #[xpath:/message/header/@id]
* </code>
*
* <p>This parser superseeds the (now removed) <code>org.mule.transport.file.SimpleFilenameParser
* </code> which has been kept in Mule 2 for compatibility. The following demonstrates how to
* achieve the same results when using the <code>ExpressionFilenameParser</code> over the <code>
* SimpleFilenameParser</code>
*
* <ul>
* <li>#[DATE] : #[function:datestamp]
* <li>#[DATE:yy-MM-dd] : #[function:datestamp-yy-MM-dd]
* <li>#[SYSTIME] : #[function:systime]
* <li>#[UUID] : #[function:uuid]
* <li>#[ORIGINALNAME] : #[header:originalFilename]
* <li>#[COUNT] : #[function:count] - note that this is a global counter.
* <li>#[<Message Property Name>] : #[header:<Message Property Name>]
* </ul>
*/
public class ExpressionFilenameParser implements FilenameParser, MuleContextAware {
public static final String DEFAULT_DATE_FORMAT = "dd-MM-yy_HH-mm-ss.SSS";
public static final String DEFAULT_EXPRESSION =
MessageFormat.format(
"{0}function:uuid{1}.dat",
ExpressionManager.DEFAULT_EXPRESSION_PREFIX,
ExpressionManager.DEFAULT_EXPRESSION_POSTFIX);
private final TemplateParser wigglyMuleParser = TemplateParser.createMuleStyleParser();
private final TemplateParser squareParser = TemplateParser.createSquareBracesStyleParser();
protected MuleContext muleContext;
public void setMuleContext(MuleContext context) {
this.muleContext = context;
}
public String getFilename(MuleMessage message, String expression) {
if (expression == null) {
expression = DEFAULT_EXPRESSION;
}
if (expression.indexOf(ExpressionManager.DEFAULT_EXPRESSION_PREFIX) > -1) {
return getFilename(message, expression, wigglyMuleParser);
} else {
return getFilename(message, expression, squareParser);
}
}
protected String getFilename(
final MuleMessage message, String expression, TemplateParser parser) {
return parser.parse(
new TemplateParser.TemplateCallback() {
public Object match(String token) {
return muleContext.getExpressionManager().evaluate(token, message);
}
},
expression);
}
}
/**
* Provides universal access for evaluating expressions embedded in Mule configurations, such as
* Xml, Java, scripting and annotations.
*
* <p>Users can register or unregister {@link ExpressionEvaluator} through this interface.
*/
public class DefaultExpressionManager implements ExpressionManager {
/** logger used by this class */
protected static final transient Log logger = LogFactory.getLog(DefaultExpressionManager.class);
// default style parser
private TemplateParser parser = TemplateParser.createMuleStyleParser();
private ConcurrentMap evaluators = new ConcurrentHashMap(8);
public void registerEvaluator(ExpressionEvaluator evaluator) {
if (evaluator == null) {
throw new IllegalArgumentException(CoreMessages.objectIsNull("evaluator").getMessage());
}
final String name = evaluator.getName();
// TODO MULE-3809 Eliminate duplicate evaluators registration
if (logger.isDebugEnabled()) {
logger.debug(
"Evaluators already contain an object named '"
+ name
+ "'. The previous object will be overwritten.");
}
evaluators.put(evaluator.getName(), evaluator);
}
/**
* Checks whether an evaluator is registered with the manager
*
* @param name the name of the expression evaluator
* @return true if the evaluator is registered with the manager, false otherwise
*/
public boolean isEvaluatorRegistered(String name) {
return evaluators.containsKey(name);
}
/**
* Removes the evaluator with the given name
*
* @param name the name of the evaluator to remove
*/
public ExpressionEvaluator unregisterEvaluator(String name) {
if (name == null) {
return null;
}
ExpressionEvaluator evaluator = (ExpressionEvaluator) evaluators.remove(name);
if (evaluator instanceof Disposable) {
((Disposable) evaluator).dispose();
}
return evaluator;
}
/**
* Evaluates the given expression. The expression should be a single expression definition with or
* without enclosing braces. i.e. "mule:serviceName" and "#[mule:serviceName]" are both valid. For
* situations where one or more expressions need to be parsed within a single text, the {@link
* org.mule.api.expression.ExpressionManager#parse(String,org.mule.api.MuleMessage,boolean)}
* method should be used since it will iterate through all expressions in a string.
*
* @param expression a single expression i.e. xpath://foo
* @param message the current message to process. The expression will evaluata on the message.
* @return the result of the evaluation. Expressions that return collection will return an empty
* collection, not null.
* @throws ExpressionRuntimeException if the expression is invalid, or a null is found for the
* expression and 'failIfNull is set to true.
*/
public Object evaluate(String expression, MuleMessage message) throws ExpressionRuntimeException {
return evaluate(expression, message, false);
}
/**
* Evaluates the given expression. The expression should be a single expression definition with or
* without enclosing braces. i.e. "mule:serviceName" and "#[mule:serviceName]" are both valid. For
* situations where one or more expressions need to be parsed within a single text, the {@link
* org.mule.api.expression.ExpressionManager#parse(String,org.mule.api.MuleMessage,boolean)}
* method should be used since it will iterate through all expressions in a string.
*
* @param expression a single expression i.e. xpath://foo
* @param message the current message to process. The expression will evaluata on the message.
* @param failIfNull determines if an exception should be thrown if expression could not be
* evaluated or returns null.
* @return the result of the evaluation. Expressions that return collection will return an empty
* collection, not null.
* @throws ExpressionRuntimeException if the expression is invalid, or a null is found for the
* expression and 'failIfNull is set to true.
*/
public Object evaluate(String expression, MuleMessage message, boolean failIfNull)
throws ExpressionRuntimeException {
String name;
if (expression == null) {
throw new IllegalArgumentException(CoreMessages.objectIsNull("expression").getMessage());
}
if (expression.startsWith(DEFAULT_EXPRESSION_PREFIX)) {
expression = expression.substring(2, expression.length() - 1);
}
int i = expression.indexOf(":");
if (i > -1) {
name = expression.substring(0, i);
expression = expression.substring(i + DEFAULT_EXPRESSION_POSTFIX.length());
} else {
name = expression;
expression = null;
}
return evaluate(expression, name, message, failIfNull);
}
/**
* Evaluates the given expression. The expression should be a single expression definition with or
* without enclosing braces. i.e. "mule:serviceName" and "#[mule:serviceName]" are both valid. For
* situations where one or more expressions need to be parsed within a single text, the {@link
* org.mule.api.expression.ExpressionManager#parse(String,org.mule.api.MuleMessage,boolean)}
* method should be used since it will iterate through all expressions in a string.
*
* @param expression a single expression i.e. xpath://foo
* @param evaluator the evaluator to use when executing the expression
* @param message the current message to process. The expression will evaluata on the message.
* @param failIfNull determines if an exception should be thrown if expression could not be
* evaluated or returns null or if an exception should be thrown if an empty collection is
* returned.
* @return the result of the evaluation. Expressions that return collection will return an empty
* collection, not null.
* @throws ExpressionRuntimeException if the expression is invalid, or a null is found for the
* expression and 'failIfNull is set to true.
*/
public Object evaluate(
String expression, String evaluator, MuleMessage message, boolean failIfNull)
throws ExpressionRuntimeException {
ExpressionEvaluator extractor = (ExpressionEvaluator) evaluators.get(evaluator);
if (extractor == null) {
throw new IllegalArgumentException(
CoreMessages.expressionEvaluatorNotRegistered(evaluator).getMessage());
}
Object result = extractor.evaluate(expression, message);
// TODO Handle empty collections || (result instanceof Collection &&
// ((Collection)result).size()==0)
if (failIfNull && (result == null)) {
throw new ExpressionRuntimeException(
CoreMessages.expressionEvaluatorReturnedNull(evaluator, expression));
}
if (logger.isDebugEnabled()) {
logger.debug(
MessageFormat.format(
"Result of expression: {0}:{1} is: {2}", evaluator, expression, result));
}
return result;
}
/**
* Evaluates expressions in a given string. This method will iterate through each expression and
* evaluate it. If a user needs to evaluate a single expression they can use {@link
* org.mule.api.expression.ExpressionManager#evaluate(String,org.mule.api.MuleMessage,boolean)}.
*
* @param expression a single expression i.e. xpath://foo
* @param message the current message to process. The expression will evaluata on the message.
* @return the result of the evaluation. Expressions that return collection will return an empty
* collection, not null.
* @throws org.mule.api.expression.ExpressionRuntimeException if the expression is invalid, or a
* null is found for the expression and 'failIfNull is set to true.
*/
public String parse(String expression, MuleMessage message) throws ExpressionRuntimeException {
return parse(expression, message, false);
}
/**
* Evaluates expressions in a given string. This method will iterate through each expression and
* evaluate it. If a user needs to evaluate a single expression they can use {@link
* org.mule.api.expression.ExpressionManager#evaluate(String,org.mule.api.MuleMessage,boolean)}.
*
* @param expression a single expression i.e. xpath://foo
* @param message the current message to process. The expression will evaluata on the message.
* @param failIfNull determines if an exception should be thrown if expression could not be
* evaluated or returns null.
* @return the result of the evaluation. Expressions that return collection will return an empty
* collection, not null.
* @throws ExpressionRuntimeException if the expression is invalid, or a null is found for the
* expression and 'failIfNull is set to true.
*/
public String parse(final String expression, final MuleMessage message, final boolean failIfNull)
throws ExpressionRuntimeException {
return parser.parse(
new TemplateParser.TemplateCallback() {
public Object match(String token) {
return evaluate(token, message, failIfNull);
}
},
expression);
}
/** Clears all registered evaluators from the manager. */
public synchronized void clearEvaluators() {
for (Iterator iterator = evaluators.values().iterator(); iterator.hasNext(); ) {
ExpressionEvaluator evaluator = (ExpressionEvaluator) iterator.next();
if (evaluator instanceof Disposable) {
((Disposable) evaluator).dispose();
}
}
evaluators.clear();
}
/**
* Determines if the expression is valid or not. This method will validate a single expression or
* expressions embedded in a string. the expression must be well formed i.e. #[bean:user]
*
* @param expression the expression to validate
* @return true if the expression evaluator is recognised
*/
public boolean isValidExpression(String expression) {
final AtomicBoolean valid = new AtomicBoolean(true);
final AtomicBoolean match = new AtomicBoolean(false);
final StringBuffer message = new StringBuffer();
parser.parse(
new TemplateParser.TemplateCallback() {
public Object match(String token) {
match.set(true);
if (token.indexOf(":") == -1) {
if (valid.get()) {
valid.compareAndSet(true, false);
}
message.append(token).append(" is malformed\n");
}
return null;
}
},
expression);
if (message.length() > 0) {
logger.warn("Expression " + expression + " is malformed: " + message.toString());
}
return match.get() && valid.get();
}
}
public GetMentionsDefinitionParser() {
patternInfo = TemplateParser.createMuleStyleParser().getStyle();
}
