org.apache.maven.project.interpolation.RegexBasedModelInterpolator Maven / Gradle / Ivy
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This library is used to not only read Maven project object model files, but to assemble inheritence
and to retrieve remote models as required.
package org.apache.maven.project.interpolation;
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE 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.
*/
import org.apache.maven.model.Model;
import org.apache.maven.model.io.xpp3.MavenXpp3Reader;
import org.apache.maven.model.io.xpp3.MavenXpp3Writer;
import org.codehaus.plexus.logging.AbstractLogEnabled;
import org.codehaus.plexus.logging.Logger;
import org.codehaus.plexus.util.StringUtils;
import org.codehaus.plexus.util.cli.CommandLineUtils;
import org.codehaus.plexus.util.introspection.ReflectionValueExtractor;
import org.codehaus.plexus.util.xml.pull.XmlPullParserException;
import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;
import java.util.Map;
import java.util.Properties;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Use a regular expression search to find and resolve expressions within the POM.
*
* @author jdcasey Created on Feb 3, 2005
* @version $Id: RegexBasedModelInterpolator.java 688884 2008-08-25 21:11:19Z jdcasey $
* @todo Consolidate this logic with the PluginParameterExpressionEvaluator, minus deprecations/bans.
*/
public class RegexBasedModelInterpolator
extends AbstractLogEnabled
implements ModelInterpolator
{
private static final Pattern EXPRESSION_PATTERN = Pattern.compile( "\\$\\{(pom\\.|project\\.|env\\.)?([^}]+)\\}" );
private Properties envars;
public RegexBasedModelInterpolator( Properties envars )
{
this.envars = envars;
}
public RegexBasedModelInterpolator()
throws IOException
{
envars = CommandLineUtils.getSystemEnvVars();
}
public Model interpolate( Model model, Map context )
throws ModelInterpolationException
{
return interpolate( model, context, true );
}
/**
* Serialize the inbound Model instance to a StringWriter, perform the regex replacement to resolve
* POM expressions, then re-parse into the resolved Model instance.
*
* NOTE: This will result in a different instance of Model being returned!!!
*
* @param model The inbound Model instance, to serialize and reference for expression resolution
* @param context The other context map to be used during resolution
* @return The resolved instance of the inbound Model. This is a different instance!
*/
public Model interpolate( Model model, Map context, boolean strict )
throws ModelInterpolationException
{
StringWriter sWriter = new StringWriter();
MavenXpp3Writer writer = new MavenXpp3Writer();
try
{
writer.write( sWriter, model );
}
catch ( IOException e )
{
throw new ModelInterpolationException( "Cannot serialize project model for interpolation.", e );
}
String serializedModel = sWriter.toString();
serializedModel = interpolateInternal( serializedModel, model, context );
StringReader sReader = new StringReader( serializedModel );
MavenXpp3Reader modelReader = new MavenXpp3Reader();
try
{
model = modelReader.read( sReader );
}
catch ( IOException e )
{
throw new ModelInterpolationException(
"Cannot read project model from interpolating filter of serialized version.", e );
}
catch ( XmlPullParserException e )
{
throw new ModelInterpolationException(
"Cannot read project model from interpolating filter of serialized version.", e );
}
return model;
}
private String interpolateInternal( String src, Model model, Map context )
throws ModelInterpolationException
{
String result = src;
Matcher matcher = EXPRESSION_PATTERN.matcher( result );
while ( matcher.find() )
{
String wholeExpr = matcher.group( 0 );
String realExpr = matcher.group( 2 );
Object value = context.get( realExpr );
if ( value == null )
{
// This may look out of place, but its here for the MNG-2124/MNG-1927 fix described in the project builder
if ( context.containsKey( realExpr ) )
{
// It existed, but was null. Leave it alone.
continue;
}
value = model.getProperties().getProperty( realExpr );
}
if ( value == null )
{
try
{
// NOTE: We've already trimmed off any leading expression parts like 'project.'
// or 'pom.', and now we have to ensure that the ReflectionValueExtractor
// doesn't try to do it again.
value = ReflectionValueExtractor.evaluate( realExpr, model, false );
}
catch ( Exception e )
{
Logger logger = getLogger();
if ( logger != null )
{
logger.debug( "POM interpolation cannot proceed with expression: " + wholeExpr + ". Skipping...", e );
}
}
}
if ( value == null )
{
value = envars.getProperty( realExpr );
}
// if the expression refers to itself, skip it.
if ( String.valueOf( value ).indexOf( wholeExpr ) > -1 )
{
throw new ModelInterpolationException( wholeExpr, "Expression value '" + value + "' references itself in '" + model.getId() + "'." );
}
if ( value != null )
{
result = StringUtils.replace( result, wholeExpr, String.valueOf( value ) );
// could use:
// result = matcher.replaceFirst( stringValue );
// but this could result in multiple lookups of stringValue, and replaceAll is not correct behaviour
matcher.reset( result );
}
/*
// This is the desired behaviour, however there are too many crappy poms in the repo and an issue with the
// timing of executing the interpolation
else
{
throw new ModelInterpolationException(
"Expression '" + wholeExpr + "' did not evaluate to anything in the model" );
}
*/
}
return result;
}
}