Merge pull request #249 from DawnScience/DAQ-146

[DAQ-146] support adding nexus object to a collection

org.eclipse.dawnsci.nexus.test/src/org/eclipse/dawnsci/nexus/builder/impl/DefaultNexusEntryBuilderTest.java

@@ -10,10 +10,12 @@
 import static org.hamcrest.Matchers.notNullValue;
 import static org.hamcrest.Matchers.nullValue;
 import static org.hamcrest.Matchers.sameInstance;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertThat;
 
 import java.util.Arrays;
 
+import org.eclipse.dawnsci.nexus.NXcollection;
 import org.eclipse.dawnsci.nexus.NXdetector;
 import org.eclipse.dawnsci.nexus.NXentry;
 import org.eclipse.dawnsci.nexus.NXinstrument;
@@ -31,8 +33,6 @@
 import org.eclipse.dawnsci.nexus.builder.NexusObjectProvider;
 import org.eclipse.dawnsci.nexus.builder.appdef.NexusApplicationBuilder;
 import org.eclipse.dawnsci.nexus.builder.data.NexusDataBuilder;
-import org.eclipse.dawnsci.nexus.builder.impl.DefaultNexusFileBuilder;
-import org.eclipse.dawnsci.nexus.builder.impl.MapBasedMetadataProvider;
 import org.eclipse.dawnsci.nexus.validation.NexusValidationException;
 import org.junit.Before;
 import org.junit.Test;
@@ -151,6 +151,27 @@ public void testAdd_namedGroup() throws NexusException {
 		assertThat(instrument.getPositioner("x"), is(sameInstance(positionerProvider.getNexusObject())));
 	}
 
+	@Test
+	public void testAdd_positionerWithCollectionName() throws NexusException {
+		entryBuilder.addDefaultGroups();
+		assertThat(nxEntry.getNumberOfGroupNodes(), is(3));
+		NXinstrument instrument = nxEntry.getInstrument();
+		assertThat(instrument.getNumberOfGroupNodes(), is(0));
+
+		AbstractNexusObjectProvider<NXpositioner> positioner = new TestPositioner("xPos");
+		positioner.setCollectionName("scannables");
+		entryBuilder.add(positioner);
+
+		assertThat(nxEntry.getNumberOfGroupNodes(), is(3));
+		assertThat(instrument.getNumberOfGroupNodes(), is(1));
+
+		NXcollection collection = instrument.getCollection("scannables");
+		assertNotNull(collection);
+		NXpositioner xPositioner = (NXpositioner) collection.getGroupNode("xPos");
+		assertNotNull(xPositioner);
+		assertThat(xPositioner, is(sameInstance(positioner.getNexusObject())));
+	}
+
 	@Test
 	public void testAdd_samplePositioner() throws NexusException {
 		entryBuilder.addDefaultGroups();

org.eclipse.dawnsci.nexus/src/org/eclipse/dawnsci/nexus/builder/AbstractNexusObjectProvider.java

@@ -89,6 +89,8 @@ public abstract class AbstractNexusObjectProvider<N extends NXobject> implements
 
 	private String defaultAxisDataFieldName = null;
 
+	private String collectionName = null;
+
 	private NexusBaseClass category = null;
 
 	private Boolean useDeviceNameInNXdata = null;
@@ -461,6 +463,14 @@ public void setCategory(NexusBaseClass category) {
 		this.category = category;
 	}
 
+	public String getCollectionName() {
+		return collectionName;
+	}
+
+	public void setCollectionName(String collectionName) {
+		this.collectionName = collectionName;
+	}
+
 	@Override
 	public Integer getDefaultAxisDimension(String primaryDataFieldName, String dataFieldName) {
 		PrimaryDataFieldModel dataFieldModel = getPrimaryDataFieldModel(primaryDataFieldName, false);

org.eclipse.dawnsci.nexus/src/org/eclipse/dawnsci/nexus/builder/NexusObjectProvider.java

@@ -14,6 +14,7 @@
 
 import java.util.List;
 
+import org.eclipse.dawnsci.nexus.NXcollection;
 import org.eclipse.dawnsci.nexus.NXdata;
 import org.eclipse.dawnsci.nexus.NXinstrument;
 import org.eclipse.dawnsci.nexus.NXobject;
@@ -88,6 +89,16 @@ public interface NexusObjectProvider<N extends NXobject> extends NexusEntryModif
 	 */
 	public NexusBaseClass getCategory();
 
+	/**
+	 * Returns the name of the collection for this {@link NexusObjectProvider}. When adding
+	 * a nexus object to a {@link NexusEntryBuilder}, if this method does not return
+	 * <code>null</code>, then the nexus object will be added to the {@link NXcollection} with this
+	 * name within the group that it would have been added to otherwise. The collection will be
+	 * created if it does not already exist.
+	 * @return collection name or <code>null</code>
+	 */
+	public String getCollectionName();
+
 	/**
 	 * Returns the name of the external HDF5 file that this device writes
 	 * its data to, or <code>null</code> if none

org.eclipse.dawnsci.nexus/src/org/eclipse/dawnsci/nexus/builder/impl/DefaultNexusEntryBuilder.java

@@ -18,7 +18,9 @@
 import java.util.List;
 
 import org.eclipse.dawnsci.analysis.api.tree.DataNode;
+import org.eclipse.dawnsci.analysis.api.tree.GroupNode;
 import org.eclipse.dawnsci.analysis.api.tree.NodeLink;
+import org.eclipse.dawnsci.nexus.NXcollection;
 import org.eclipse.dawnsci.nexus.NXdata;
 import org.eclipse.dawnsci.nexus.NXentry;
 import org.eclipse.dawnsci.nexus.NXinstrument;
@@ -66,10 +68,11 @@ public class DefaultNexusEntryBuilder implements NexusEntryBuilder {
 	 * Creates a new {@link DefaultNexusEntryBuilder}. This constructor should only be called
 	 * by {@link DefaultNexusFileBuilder}.
 	 * @param nexusNodeFactory node factory
-	 * @param entryName TODO
+	 * @param entryName name of entry
 	 * @param nxEntry entry to wrap
 	 */
-	protected DefaultNexusEntryBuilder(final NexusNodeFactory nexusNodeFactory, String entryName, final NXentry nxEntry) {
+	protected DefaultNexusEntryBuilder(final NexusNodeFactory nexusNodeFactory,
+			String entryName, final NXentry nxEntry) {
 		this.nexusNodeFactory = nexusNodeFactory;
 		this.nxEntry = nxEntry;
 		this.entryName = entryName;
@@ -250,7 +253,6 @@ public DataNode getDataNode(String relativePath) throws NexusException {
 
 	/**
 	 * Adds the default groups for the entry. Subclasses may override as appropriate.
-	 * @return
 	 */
 	@Override
 	public void addDefaultGroups() {
@@ -310,10 +312,13 @@ protected <N extends NXobject> void addGroupToNexusTree(NexusObjectProvider<N> n
 			final String name = nexusObjectProvider.getName();
 			final NexusBaseClass category = nexusObjectProvider.getCategory();
 
+			// find the parent group
 			NXobject parentGroup = null;
 			if (category != null) {
+				// if a category is specified, the parent group is the first group for this category
 				parentGroup = findGroupForCategory(category);
 			} else {
+				// otherwise the parent group is the first group we can add this type of object to
 				for (final NXobject group : defaultGroups) {
 					if (group.canAddChild(nexusObject)) {
 						parentGroup = group;
@@ -324,10 +329,33 @@ protected <N extends NXobject> void addGroupToNexusTree(NexusObjectProvider<N> n
 					throw new NexusException("Cannot find a parent group that accepts a " + nexusObject.getNexusBaseClass());
 				}
 			}
+
+			// if a collection name is specified, get the parent collection - creating it if necessary
+			String collectionName = nexusObjectProvider.getCollectionName();
+			if (collectionName != null) {
+				parentGroup = getCollection(parentGroup, collectionName);
+			}
 
 			parentGroup.addGroupNode(name, nexusObject);
 		}
 	}
+
+	private NXcollection getCollection(NXobject group, String collectionName) {
+		NXcollection collection = null;
+
+		GroupNode collectionGroup = group.getGroupNode(collectionName);
+		if (collectionGroup == null) {
+			collection = nexusNodeFactory.createNXcollection();
+			group.addGroupNode(collectionName, collection);
+		} else if (collectionGroup instanceof NXcollection) {
+			collection = (NXcollection) collectionGroup;
+		} else {
+			throw new IllegalArgumentException("Cannot add collection " + collectionName +
+					". A child group with that name already exists");
+		}
+
+		return collection;
+	}
 
 	private NXobject findGroupForCategory(NexusBaseClass category) throws NexusException {
 		if (category == NexusBaseClass.NX_ENTRY) {