org.codehaus.plexus.interpolation
Class PrefixAwareRecursionInterceptor

java.lang.Object
  org.codehaus.plexus.interpolation.PrefixAwareRecursionInterceptor

All Implemented Interfaces:

RecursionInterceptor

public class PrefixAwareRecursionInterceptor
extends java.lang.Object
implements RecursionInterceptor

RecursionInterceptor implementation that provides support for expressions with multiple synonyms, such as project.build.directory == pom.build.directory == build.directory in Maven's POM.

Version:

$Id: PrefixAwareRecursionInterceptor.java 7529 2008-07-20 20:24:21Z olamy $

Author:

jdcasey

Field Summary

static java.lang.String	DEFAULT_END_TOKEN
static java.lang.String	DEFAULT_START_TOKEN

Constructor Summary

PrefixAwareRecursionInterceptor(java.util.Collection possiblePrefixes)
Use the specified expression prefixes to detect synonyms.

PrefixAwareRecursionInterceptor(java.util.Collection possiblePrefixes, boolean watchUnprefixedExpressions)
Use the specified expression prefixes to detect synonyms, and specify whether unprefixed expressions can be considered synonyms.

Method Summary

void	expressionResolutionFinished(java.lang.String expression) Signal to the interceptor that the all efforts to resolve the given expression have completed - whether successfully or not is irrelevant - and that the expression should not be tracked for recursion any longer.
void	expressionResolutionStarted(java.lang.String expression) Log the intention to start resolving the given expression.
java.util.List	getExpressionCycle(java.lang.String expression) When an expression is determined to be a recursive reference, this method returns the sublist of tracked expressions that participate in this cycle.
boolean	hasRecursiveExpression(java.lang.String expression) Check whether the given value contains an expression that is currently being tracked by this interceptor.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_START_TOKEN

public static final java.lang.String DEFAULT_START_TOKEN

See Also:

Constant Field Values

DEFAULT_END_TOKEN

public static final java.lang.String DEFAULT_END_TOKEN

See Also:

Constant Field Values

Constructor Detail

PrefixAwareRecursionInterceptor

public PrefixAwareRecursionInterceptor(java.util.Collection possiblePrefixes,
                                       boolean watchUnprefixedExpressions)

Use the specified expression prefixes to detect synonyms, and specify whether unprefixed expressions can be considered synonyms.

Parameters:

possiblePrefixes - The collection of expression prefixes supported

watchUnprefixedExpressions - Whether to consider unprefixed expressions as synonyms

PrefixAwareRecursionInterceptor

public PrefixAwareRecursionInterceptor(java.util.Collection possiblePrefixes)

Use the specified expression prefixes to detect synonyms. Consider unprefixed expressions synonyms as well.

Parameters:

possiblePrefixes - The collection of expression prefixes supported

Method Detail

hasRecursiveExpression

public boolean hasRecursiveExpression(java.lang.String expression)

Description copied from interface: RecursionInterceptor

Check whether the given value contains an expression that is currently being tracked by this interceptor. If so, that expression is still in the process of being resolved, and this constitutes an expression cycle.

Specified by:

hasRecursiveExpression in interface RecursionInterceptor

Parameters:

expression - The value to check for expression cycles.

Returns:

True if the value contains tracked expressions; false otherwise.

expressionResolutionFinished

public void expressionResolutionFinished(java.lang.String expression)

Description copied from interface: RecursionInterceptor

Signal to the interceptor that the all efforts to resolve the given expression have completed - whether successfully or not is irrelevant - and that the expression should not be tracked for recursion any longer.

Specified by:

expressionResolutionFinished in interface RecursionInterceptor

Parameters:

expression - The expression to stop tracking.

expressionResolutionStarted

public void expressionResolutionStarted(java.lang.String expression)

Description copied from interface: RecursionInterceptor

Log the intention to start resolving the given expression. This signals the interceptor to start tracking that expression to make sure it doesn't come up again until after it has been resolved (or, fails to resolve).

Specified by:

expressionResolutionStarted in interface RecursionInterceptor

Parameters:

expression - The expression to be resolved.

getExpressionCycle

public java.util.List getExpressionCycle(java.lang.String expression)

When an expression is determined to be a recursive reference, this method returns the sublist of tracked expressions that participate in this cycle. Otherwise, if the expression isn't present in the in-process stack, return Collections.EMPTY_LIST. Also, if the expression doesn't have a matched prefix from this interceptor's list, and unprefixed expressions aren't allowed then return Collections.EMPTY_LIST.

Specified by:

getExpressionCycle in interface RecursionInterceptor

Returns:

The list of expressions that participate in the cycle caused by the given expression.