PT-1987-projects: Added PrimaryEntityProperty and AbstractPrimaryEnti…

…tyProperty.

components/entities/api/src/main/java/org/phenotips/entities/PrimaryEntityProperty.java

@@ -0,0 +1,57 @@
+/*
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see http://www.gnu.org/licenses/
+ */
+package org.phenotips.entities;
+
+import org.xwiki.stability.Unstable;
+
+/**
+ * A property of a {@link PrimaryEntity}, which in turn is another type of entity. For example, a Project has an image,
+ * a Patient has a template.
+ *
+ * @param <E> the type of the property
+ * @version $Id$
+ * @since 1.3M2
+ */
+@Unstable("New API introduced in 1.3")
+public interface PrimaryEntityProperty<E extends PrimaryEntity> extends PrimaryEntity
+{
+    /**
+     * Returns the property, if exists.
+     *
+     * @return a property, or null
+     */
+    E get();
+
+    /**
+     * Sets the property.
+     *
+     * @param property the property
+     * @return {@code true} if the property was successfully set, or was already set, {@code false} if the
+     *         operation failed
+     */
+    boolean set(E property);
+
+    /**
+     * Removes the property.
+     *
+     * @return {@code true} if the property was successfully removed, or if it wasn't set, {@code false} if the
+     *         operation failed
+     */
+    boolean remove();
+
+}

components/entities/api/src/main/java/org/phenotips/entities/internal/AbstractPrimaryEntityProperty.java

@@ -0,0 +1,85 @@
+/*
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see http://www.gnu.org/licenses/
+ */
+package org.phenotips.entities.internal;
+
+import org.phenotips.entities.PrimaryEntity;
+import org.phenotips.entities.PrimaryEntityProperty;
+
+import org.xwiki.model.reference.DocumentReference;
+
+import java.util.Collection;
+import java.util.Iterator;
+
+import com.xpn.xwiki.doc.XWikiDocument;
+
+/**
+ * Base class for implementing PrimaryEntityProperty. The implementation is done as a container of one object.
+ *
+ * @param <E> the type of entity of the property
+ * @version $Id$
+ * @since 1.3M2
+ */
+public abstract class AbstractPrimaryEntityProperty<E extends PrimaryEntity>
+    extends AbstractContainerPrimaryEntityGroup<E>
+    implements PrimaryEntityProperty<E>
+{
+    protected AbstractPrimaryEntityProperty(XWikiDocument document)
+    {
+        super(document);
+    }
+
+    protected AbstractPrimaryEntityProperty(DocumentReference reference)
+    {
+        super(reference);
+    }
+
+    @Override
+    public E get()
+    {
+        Collection<E> members = this.getMembers();
+        Iterator<E> iterator = members.iterator();
+        if (iterator.hasNext()) {
+            return iterator.next();
+        } else {
+            return null;
+        }
+    }
+
+    @Override
+    public boolean set(E property)
+    {
+        if (property == null) {
+            return false;
+        }
+        if (!this.remove()) {
+            return false;
+        }
+        return addMember(property);
+    }
+
+    @Override
+    public boolean remove()
+    {
+        E property = this.get();
+        if (property == null) {
+            return true;
+        } else {
+            return this.removeMember(property);
+        }
+    }
+}