org.codehaus.plexus.interpolation.SimpleRecursionInterceptor Maven / Gradle / Ivy
package org.codehaus.plexus.interpolation;
/*
* Copyright 2001-2008 Codehaus Foundation.
*
* Licensed 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.
*/
import java.util.Collections;
import java.util.List;
import java.util.Stack;
/**
* Simplest implementation of a {@link RecursionInterceptor}, which checks whether
* the existing interpolation effort is already attempting to resolve an exact
* expression, but has not finished. This will not catch synonym expressions, as
* are found in Maven (${project.build.directory}, ${pom.build.directory}, and
* ${build.directory} are synonyms).
*
* @author jdcasey
* @version $Id$
*/
public class SimpleRecursionInterceptor
implements RecursionInterceptor
{
private Stack expressions = new Stack();
/**
* {@inheritDoc}
*/
public void expressionResolutionFinished( String expression )
{
expressions.pop();
}
/**
* {@inheritDoc}
*/
public void expressionResolutionStarted( String expression )
{
expressions.push( expression );
}
/**
* Check whether the current expression is already present in the in-process
* stack.
*/
public boolean hasRecursiveExpression( String expression )
{
return expressions.contains( 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
* {@link Collections#EMPTY_LIST}.
*/
public List getExpressionCycle( String expression )
{
int idx = expressions.indexOf( expression );
if ( idx < 0 )
{
return Collections.EMPTY_LIST;
}
else
{
return expressions.subList( idx, expressions.size() );
}
}
}
© 2015 - 2024 Weber Informatics LLC | Privacy Policy