Author: michiel
Date: 2010-03-30 11:57:03 +0200 (Tue, 30 Mar 2010)
New Revision: 41663
Modified:
mmbase/branches/MMBase-1_9/core/src/main/java/org/mmbase/bridge/util/Queries.java
Log:
added a utility funciton 'getSubQuery'
Modified:
mmbase/branches/MMBase-1_9/core/src/main/java/org/mmbase/bridge/util/Queries.java
===================================================================
---
mmbase/branches/MMBase-1_9/core/src/main/java/org/mmbase/bridge/util/Queries.java
2010-03-30 09:48:43 UTC (rev 41662)
+++
mmbase/branches/MMBase-1_9/core/src/main/java/org/mmbase/bridge/util/Queries.java
2010-03-30 09:57:03 UTC (rev 41663)
@@ -2047,5 +2047,90 @@
}
+ /**
+ * Given a Query, and Node, produces a new query, where the first part of
the query is replaced by the Node.
+ * So, e.g. if you have a query mags,posrel,news,posrel,images and a news
node, you can feed this query, and
+ * the node into this method (with step is 2), to produce a query
news,posrel,images, where the start node is the given news node. All
+ * constraints, nodes, and aliases on the remainings steps are copied.
+ *
+ * The query is a NodeQuery, where the NodeStep is the (normal) step after
the node.
+ *
+ * @param q The query to base the new query
+ * @param node The node to start the query with. If this is
<code>null</code> then step must be 0, and the original query will be
+ * returned, only converted to a NodeQuery for the first step.
+ * @param The element step. The first non-relation step after the first
step where the node is fixed.
+ * @exception ClassCastException if step+1 is not a relationstep. (This
restriction may perhaps be removed).
+ * @since MMBase-1.9.3
+ */
+ public static NodeQuery getSubQuery(final Query q, final Node node, int
step) {
+ Cloud cloud = q.getCloud();
+ NodeQuery subQuery = cloud.createNodeQuery();
+
+ if (step % 2 != 0) {
+ throw new UnsupportedOperationException("Only non-relation steps
are supported, so step must be even (now " + step + ")");
+ }
+ if (node != null) {
+ Step firstStep = q.getSteps().get(step - 2);
+ Step copyFirstStep =
subQuery.addStep(cloud.getNodeManager(firstStep.getTableName()));
+ subQuery.addNode(copyFirstStep, node);
+ addConstraint(subQuery, copyConstraint(q.getConstraint(),
firstStep, subQuery, copyFirstStep));
+ } else {
+ if (step == 0) {
+ Step sourceStep = q.getSteps().get(0);
+ Step destStep =
subQuery.addStep(cloud.getNodeManager(sourceStep.getTableName()));
+ addConstraint(subQuery, copyConstraint(q.getConstraint(),
sourceStep, subQuery, destStep));
+ subQuery.setAlias(destStep, sourceStep.getAlias());
+ addConstraint(subQuery, copyConstraint(q.getConstraint(),
sourceStep, subQuery, destStep));
+ step += 2;
+ } else {
+ throw new IllegalArgumentException();
+ }
+ }
+ for (int i = step - 1; i < q.getSteps().size(); i+=2) {
+ RelationStep sourceRelStep = (RelationStep) q.getSteps().get(i);
+
+ // Seems a bit cumbersome...
+ Integer role = sourceRelStep.getRole();
+ log.debug("Found role " + role);
+ String roleAsString = role == null ? null :
cloud.getNode(role).getStringValue("sname");
+
+ RelationStep destRelStep =
subQuery.addRelationStep(cloud.getNodeManager(sourceRelStep.getNext().getTableName()),
+ roleAsString,
+
RelationStep.DIRECTIONALITY_DESCRIPTIONS[sourceRelStep.getDirectionality()]);
+
+ addConstraint(subQuery, copyConstraint(q.getConstraint(),
sourceRelStep, subQuery, destRelStep));
+ if (sourceRelStep.getNodes() != null) {
+ for (int n : sourceRelStep.getNodes()) {
+ subQuery.addNode(destRelStep, n);
+ }
+ }
+ subQuery.setAlias(destRelStep, sourceRelStep.getAlias());
+
+
+ Step sourceStep = sourceRelStep.getNext();
+ Step destStep = destRelStep.getNext();
+ addConstraint(subQuery, copyConstraint(q.getConstraint(),
sourceStep, subQuery, destStep));
+
+ if (sourceStep.getNodes() != null) {
+ for (int n : sourceStep.getNodes()) {
+ subQuery.addNode(destStep, n);
+ }
+ }
+ subQuery.setAlias(destStep, sourceStep.getAlias());
+ copySortOrders(q.getSortOrders(), sourceRelStep, subQuery,
destRelStep);
+ copySortOrders(q.getSortOrders(), sourceStep, subQuery, destStep);
+ }
+ if (log.isDebugEnabled()) {
+ log.debug("Setting nodeStep to " + subQuery.getSteps().get(2));
+ }
+ if (node != null) {
+ subQuery.setNodeStep(subQuery.getSteps().get(2));
+ } else {
+ subQuery.setNodeStep(subQuery.getSteps().get(0));
+ }
+ subQuery.setDistinct(true);
+ return subQuery;
+ }
+
}
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