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Section One: DSpace Logical Item filtering (org.dspace.content.logic.*)

Inspired by the powerful conditional filters in XOAI, this component offers a simple but flexible way to write logical statements and tests, and use the results of those tests in other services or DSpace code.

LogicalStatement

LogicalStatement is a simple interface ultimately implemented by all the other interfaces and classes described below. It just requires that a class implements a Boolean getResult(context, item) method.

Filters

Filters are at the root of any test definition, and it is the filter ID that is used to load up the filter in spring configurations for other services, or with DSpace Service Manager.

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There is one simple implementation of Filter included - DefaultFilter.

Operators

Operators are the basic logical building blocks that implement operations like AND, OR, NOT, NAND and NOR. An Operator can contain any number of other Operators or Conditions.

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(x AND (y OR z) AND a AND (b OR NOT(d))

Conditions

Conditions are where the actual DSpace item evaluation code is written. A condition accepts a Map<String, Object> map of parameters. Conditions don’t contain any other LogicalStatement classes – the are at the bottom of the chain.

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Typically, commonly used Conditions will be defined as beans elsewhere in the spring config and then referenced inside Filters and Operators to create more complex statements.

Configuring Filters in Spring

Conditions, Operators and Filters are all defined in ${dspace}/config/spring/api/item-filters.xml

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<!-- An example of an OpenAIRE compliance filter based on the same rules in xoai.xml
      some sub-statements are defined within this bean, and some are referenced from earlier definitions
-->
<bean id="openaire_filter" class="org.dspace.content.logic.DefaultFilter">
    <property name="statement">
        <bean class="org.dspace.content.logic.operator.And">
            <property name="statements">
                <list>
                    <!-- Has a non-empty title -->
                    <bean id="has-title_condition"
                          class="org.dspace.content.logic.condition.MetadataValueMatchCondition">
                        <property name="parameters">
                            <map>
                                <entry key="field" value="dc.title" />
                                <entry key="pattern" value=".*" />
                            </map>
                        </property>
                    </bean>
                    <!-- AND has a non-empty author -->
                    <bean id="has-author_condition"
                          class="org.dspace.content.logic.condition.MetadataValueMatchCondition">
                        <property name="parameters">
                            <map>
                                <entry key="field" value="dc.contributor.author" />
                                <entry key="pattern" value=".*" />
                            </map>
                        </property>
                    </bean>
                    <!-- AND has a valid DRIVER document type (defined earlier) -->
                    <ref bean="driver-document-type_condition" />
                    <!-- AND (the item is publicly accessible OR withdrawn) -->
                    <bean class="org.dspace.content.logic.operator.Or">
                        <property name="statements">
                            <list>
                                <!-- item is public, defined earlier -->
                                <ref bean="item-is-public_condition" />
                                <!-- OR item is withdrawn, for tombstoning -->
                                <bean class="org.dspace.content.logic.condition.IsWithdrawnCondition">
                                    <property name="parameters"><map></map></property>
                                </bean>
                            </list>
                        </property>
                    </bean>
                    <!-- AND the dc.relation is a valid OpenAIRE identifier
                          (starts with "info:eu-repo/grantAgreement/") -->
                    <bean id="has-openaire-relation_condition"
                          class="org.dspace.content.logic.condition.MetadataValueMatchCondition">
                        <property name="parameters">
                            <map>
                                <entry key="field" value="dc.relation" />
                                <entry key="pattern" value="^info:eu-repo/grantAgreement/" />
                            </map>
                        </property>
                    </bean>
                </list>
            </property>
        </bean>
    </property>
</bean>

Running Tests on the Command Line

There is a launcher command that can arbitrarily run tests on an item or all items, eg.

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A simple true or false is printed for each item tested.

Using Filters in other Spring Services

The Filter beans can be referenced (or defined) in other services, for instance, here is adding the bean we configured earlier, as a filterService to a new FilteredDOIIdentifierProvider:

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In the TestLogicRunner, you can see a way to get the filters by name using the DSpaceServiceManager as well.

Section Two: DOI Filtered Provider

New FilteredProvider: DOIIdentifierProvider

DOIIdentifierProvider now extends a base FilteredIdentifierProvider, which looks for any configured filters and only allows minting DOIs for items where the filter returns true

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Where the "openaire_filter" reference is the ID of a filter bean defined in item-filters.xml

New Curation Task:

In DSpace 5 and 6 implementations of this feature, JSPUI and XMLUI buttons were added to the Edit Item administrative pages so that DOIs could be manually registered (queued for registration) by administrators, explicitly skipping the filter.

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