plugin.setArtifactId(gs.artifactId);
                plugin.setVersion(gs.version);

                plugin.setLocation("", location);
                plugin.setLocation("groupId", location);
                plugin.setLocation("artifactId", location);
                plugin.setLocation("version", location);

                Plugin existing = plugins.get(plugin);
                if (existing != null) {

            build = new Build();
            model.setBuild(build);
            model.setLocation("build", location);
        }

        Plugin sitePlugin = findSitePlugin(build);

        if (sitePlugin == null) {
            sitePlugin = new Plugin();
            sitePlugin.setArtifactId("maven-site-plugin");
            sitePlugin.setLocation("artifactId", location);

    } // -- String getModelId()

    /**
     * Set the path/URL of the POM or {@code null} if unknown.
     *
     * @param location
     */
    public void setLocation(String location) {
        this.location = location;
    } // -- void setLocation( String )

    /**
     * Set the identifier of the POM in the format {@code
     * <groupId>:<artifactId>:<version>}.
     *
     * @param modelId
     */

                    problems.add(new ModelProblemCollectorRequest(Severity.ERROR, Version.BASE)
                            .setMessage("Failed to interpolate value " + value + ": " + e.getMessage())
                            .setLocation(target.getLocation(locationKey))
                            .setException(e));
                }
            }
        }
        for (Profile profile : interpolatedActivations) {

                putAll(merged, source.getProperties(), CHILD_DIRECTORY_PROPERTY);
                merged.putAll(target.getProperties());
            }
            target.setProperties(merged);
            target.setLocation(
                    "properties",
                    InputLocation.merge(
                            target.getLocation("properties"), source.getLocation("properties"), sourceDominant));
        }

        if (defaultPlugins == null) {
            problems.add(new ModelProblemCollectorRequest(Severity.ERROR, Version.BASE)
                    .setMessage("Unknown packaging: " + packaging)
                    .setLocation(model.getLocation("packaging")));
        } else if (!defaultPlugins.isEmpty()) {
            Model lifecycleModel = new Model();
            lifecycleModel.setBuild(new Build());

            problems.add(new ModelProblemCollectorRequest(Severity.ERROR, Version.BASE)
                    .setMessage("The property name is required to activate the profile " + profile.getId())
                    .setLocation(property.getLocation("")));
            return false;
        }

        String sysValue = context.getUserProperties().get(name);
        if (sysValue == null) {

            problems.add(new ModelProblemCollectorRequest(Severity.ERROR, Version.BASE)
                    .setMessage("Failed to determine Java version for profile " + profile.getId())
                    .setLocation(activation.getLocation("jdk")));
            return false;
        }

        if (jdk.startsWith("!")) {
            return !version.startsWith(jdk.substring(1));
        } else if (isRange(jdk)) {
            try {

                        .setMessage(
                                "Failed to determine activation for profile " + profile.getId() + ": " + e.getMessage())
                        .setLocation(profile.getLocation(""))
                        .setException(e));
                return false;
            }
        }
        return isActive;
    }

     *
     * @param field The key of the field, must not be
     * <code>null</code>.
     * @param location The location of the field, may be
     * <code>null</code>.
     */
    public void setLocation(Object field, InputLocation location);