*
     * @param properties The map containing key-value pairs to be interpolated.
     * @param callback The function to resolve variable values not found in the map.
     */
    default void interpolate(@Nonnull Map<String, String> properties, @Nullable UnaryOperator<String> callback) {
        interpolate(properties, callback, null, true);
    }

    /**
     * Interpolates the values in the given map using the provided callback function.
     *

                    String value = it.next();
                    String inter = interpolate(value);
                    if (value != inter) {
                        it.set(inter);
                    }
                }
            }
        }

        private String interpolate(String value) {
            return interpolator.interpolate(value);
        }
    }

                    if (String.class == value.getClass()) {
                        String interpolated = ctx.interpolate((String) value);

                        if (interpolated != null && !interpolated.equals(value)) {
                            try {
                                entry.setValue(interpolated);
                            } catch (UnsupportedOperationException ignore) {

            for (ValueSource vs : valueSources) {
                interpolator.addValueSource(vs);
            }

            for (InterpolationPostProcessor postProcessor : postProcessors) {
                interpolator.addPostProcessor(postProcessor);
            }

            try {
                try {
                    result = interpolator.interpolate(result, recursionInterceptor);

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 {

        RegexBasedInterpolator interpolator = new RegexBasedInterpolator();

        interpolator.addValueSource(new PropertiesBasedValueSource(request.getUserProperties()));

        interpolator.addValueSource(new PropertiesBasedValueSource(request.getSystemProperties()));

        try {
            interpolator.addValueSource(new EnvarBasedValueSource());
        } catch (IOException e) {

      <releases>
        <!-- That's the boolean POM field we would like to interpolate -->
        <enabled>${releasesEnabled}</enabled>
      </releases>
    </repository>
  </repositories>

  <build>
    <resources>
      <resource>
        <directory>src/main/resources</directory>
        <!-- That's the boolean POM field we would like to interpolate -->
        <filtering>${filter.resources}</filtering>
      </resource>

        } finally {
            getInterpolator().clearAnswers();
        }
    }

    @Override
    protected Interpolator createInterpolator() {
        StringSearchInterpolator interpolator = new StringSearchInterpolator();
        interpolator.setCacheAnswers(true);

        return interpolator;
    }

    private static final class InterpolateObjectAction implements PrivilegedAction<ModelInterpolationException> {

    /**
     * @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