public interface ModelInterpolator {

    /**
     * Interpolates expressions in the specified model. Note that implementations are free to either interpolate the
     * provided model directly or to create a clone of the model and interpolate the clone. Callers should always use
     * the returned model and must not rely on the input model being updated.
     *
     * @param model The model to interpolate, must not be {@code null}.

                    fileString = interpolator.interpolate(fileString, "").replace("\\", "/");
                    File file = new File(fileString);
                    return !file.exists();
                }
            } catch (InterpolationException e) {
                if (logger.isDebugEnabled()) {
                    logger.debug("Failed to interpolate missing file location for profile activator: " + fileString, e);
                } else {

            }
        });

        interpolator.addValueSource(new MapBasedValueSource(context.getProjectProperties()));
        interpolator.addValueSource(new MapBasedValueSource(context.getUserProperties()));
        interpolator.addValueSource(new MapBasedValueSource(context.getSystemProperties()));

        String absolutePath = interpolator.interpolate(path, "");

    /**
     * @deprecated Use {@link ModelInterpolator#interpolate(Model, File, ProjectBuilderConfiguration, boolean)} instead.
     */
    @Deprecated
    Model interpolate(Model project, Map<String, ?> context) throws ModelInterpolationException;

    /**
     * @deprecated Use {@link ModelInterpolator#interpolate(Model, File, ProjectBuilderConfiguration, boolean)} instead.
     */
    @Deprecated

        }

        toolchains = interpolate(toolchains, request, problems);

        return toolchains;
    }

    private PersistedToolchains interpolate(
            PersistedToolchains toolchains, ToolchainsBuilderRequest request, List<BuilderProblem> problems) {

        RegexBasedInterpolator interpolator = new RegexBasedInterpolator();

        }

        try {
            path = profileActivationFilePathInterpolator.interpolate(path, context);
        } catch (InterpolationException e) {
            problems.add(
                    BuilderProblem.Severity.ERROR,
                    ModelProblem.Version.BASE,
                    "Failed to interpolate file location " + path + " for profile " + profile.getId() + ": "
                            + e.getMessage(),

    interface Transformer {
        /**
         * Interpolate the value read from the xml document
         *
         * @param source    The source value
         * @param fieldName A description of the field being interpolated. The implementation may use this to
         *                  log stuff.
         * @return the interpolated value
         */
        String transform(String source, String fieldName);
    }

 */
package org.apache.maven.project.interpolation;

import java.io.IOException;
import java.util.Properties;

import org.apache.maven.project.path.PathTranslator;
import org.codehaus.plexus.interpolation.Interpolator;
import org.codehaus.plexus.interpolation.RegexBasedInterpolator;

/**
 * Use a regular expression search to find and resolve expressions within the POM.
 *

        if (path == null || path.isEmpty()) {
            // TODO This replacing shouldn't be necessary as user.home should be in the
            // context of the container and thus the value would be interpolated by Plexus
            String basedir = System.getProperty(basedirSysProp);
            if (basedir == null) {
                basedir = System.getProperty("user.dir");
            }

 have properties file (something I would like to avoid) say they don't
 contribute in any meaningful way to information in the POM. For example a
 properties file could be used the specify $ so it can be interpolated in
 <developerConnection/> but you couldn't use a properties file to specify the
 version of your project say. Anyway, food for thought to begin with.

 - elements that are critical for pom dissemination