#755 added Package filter

based on docs https://docs.gitlab.com/ee/api/packages.html and inspired by GroupProjectsFilter

src/main/java/org/gitlab4j/api/Constants.java

@@ -131,6 +131,52 @@ public interface Constants {
         }
     }
 
+    /** Enum to use for ordering the results of getPackages(). */
+    public enum PackageOrderBy {
+
+        NAME, CREATED_AT, VERSION, TYPE, PROJECT_PATH;
+
+        private static JacksonJsonEnumHelper<PackageOrderBy> enumHelper = new JacksonJsonEnumHelper<>(PackageOrderBy.class);
+
+        @JsonCreator
+        public static PackageOrderBy forValue(String value) {
+            return enumHelper.forValue(value);
+        }
+
+        @JsonValue
+        public String toValue() {
+            return (enumHelper.toString(this));
+        }
+
+        @Override
+        public String toString() {
+            return (enumHelper.toString(this));
+        }
+    }
+
+    /** Enum to use for filtering the results of getPackages(). */
+    public enum PackageStatus {
+
+        DEFAULT, HIDDEN, PROCESSING;
+
+        private static JacksonJsonEnumHelper<PackageStatus> enumHelper = new JacksonJsonEnumHelper<>(PackageStatus.class);
+
+        @JsonCreator
+        public static PackageStatus forValue(String value) {
+            return enumHelper.forValue(value);
+        }
+
+        @JsonValue
+        public String toValue() {
+            return (enumHelper.toString(this));
+        }
+
+        @Override
+        public String toString() {
+            return (enumHelper.toString(this));
+        }
+    }
+
     /** Enum to use for ordering the results of getProjects(). */
     public enum ProjectOrderBy {
 

src/main/java/org/gitlab4j/api/models/PackageFilter.java

+package org.gitlab4j.api.models;
+
+import org.gitlab4j.api.Constants.PackageStatus;
+import org.gitlab4j.api.Constants.PackageOrderBy;
+import org.gitlab4j.api.Constants.SortOrder;
+import org.gitlab4j.api.GitLabApiForm;
+
+/**
+ *  This class is used to filter Projects when getting lists of projects for a specified group.
+ */
+public class PackageFilter {
+
+    private Boolean excludeSubgroups;
+    private PackageOrderBy orderBy;
+    private SortOrder sort;
+    private PackageType packageType;
+    private String packageName;
+    private Boolean includeVersionless;
+    private PackageStatus status;
+
+    /**
+     * Exclude Subgroups.
+     *
+     * @param excludeSubgroups if true, packages from projects from subgroups are not listed.
+     * @return the reference to this ProjectFilter instance
+     */
+    public PackageFilter withExcludeSubgroups(Boolean excludeSubgroups) {
+        this.excludeSubgroups = excludeSubgroups;
+        return (this);
+    }
+
+    /**
+     * Return projects ordered by created_at, name, version, type, or project_path
+     *
+     * @param orderBy specifies what field to order by
+     * @return the reference to this ProjectFilter instance
+     */
+    public PackageFilter withOrderBy(PackageOrderBy orderBy) {
+        this.orderBy = orderBy;
+        return (this);
+    }
+
+    /**
+     * Return projects sorted in asc or desc order. Default is desc.
+     *
+     * @param sort sort direction, ASC or DESC
+     * @return the reference to this ProjectFilter instance
+     */
+    public PackageFilter withSortOder(SortOrder sort) {
+        this.sort = sort;
+        return (this);
+    }
+
+    /**
+     * Filter the returned packages by type.
+     *
+     * @param packageType One of conan, maven, npm, pypi, composer, nuget, helm, generic or golang
+     * @return the reference to this ProjectFilter instance
+     */
+    public PackageFilter withPackageType(PackageType packageType) {
+        this.packageType = packageType;
+        return (this);
+    }
+
+    /**
+     * Filter the project packages with a fuzzy search by name
+     *
+     * @param packageName
+     * @return the reference to this ProjectFilter instance
+     */
+    public PackageFilter withPackageName(String packageName) {
+        this.packageName = packageName;
+        return (this);
+    }
+
+    /**
+     * @param includeVersionless if true, versionless packages are included in the response
+     * @return the reference to this ProjectFilter instance
+     */
+    public PackageFilter withIncludeVersionless(Boolean includeVersionless) {
+        this.includeVersionless = includeVersionless;
+        return (this);
+    }
+
+    /**
+     * Filter the returned packages by status.
+     *
+     * @param status One of default (default), hidden, or processing
+     * @return the reference to this ProjectFilter instance
+     */
+    public PackageFilter withStatus(PackageStatus status) {
+        this.status = status;
+        return (this);
+    }
+
+    /**
+     * Get the query params specified by this filter.
+     *
+     * @return a GitLabApiForm instance holding the query parameters for this ProjectFilter instance
+     */
+    public GitLabApiForm getQueryParams() {
+        return (new GitLabApiForm()
+            .withParam("order_by", orderBy)
+            .withParam("sort", sort)
+            .withParam("exclude_subgroups", excludeSubgroups)
+            .withParam("package_type", packageType)
+            .withParam("package_name", packageName)
+            .withParam("include_versionless", includeVersionless)
+            .withParam("status", status)
+        );
+    }
+}