#919 - io.ebean package initial

src/main/java/io/ebeaninternal/server/deploy/ChainedBeanQueryAdapter.java

@@ -0,0 +1,96 @@
+package io.ebeaninternal.server.deploy;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.List;
+
+import io.ebean.event.BeanQueryAdapter;
+import io.ebean.event.BeanQueryRequest;
+
+/**
+ * Handles multiple BeanQueryAdapter for a given entity type.
+ */
+public class ChainedBeanQueryAdapter implements BeanQueryAdapter {
+
+	private static final Sorter SORTER = new Sorter();
+
+	private final List<BeanQueryAdapter> list;
+
+	private final BeanQueryAdapter[] chain;
+
+	/**
+	 * Construct given the list of BeanQueryAdapter's.
+	 */
+	public ChainedBeanQueryAdapter(List<BeanQueryAdapter> list) {
+		this.list = list;
+		BeanQueryAdapter[] c = list.toArray(new BeanQueryAdapter[list.size()]);
+		Arrays.sort(c, SORTER);
+		this.chain = c;
+	}
+
+	/**
+	 * Register a new BeanQueryAdapter and return the resulting chain.
+	 */
+	public ChainedBeanQueryAdapter register(BeanQueryAdapter c) {
+		if (list.contains(c)){
+			return this;
+		} else {
+			List<BeanQueryAdapter> newList = new ArrayList<>();
+			newList.addAll(list);
+			newList.add(c);
+
+			return new ChainedBeanQueryAdapter(newList);
+		}
+	}
+
+	/**
+	 * De-register a BeanQueryAdapter and return the resulting chain.
+	 */
+	public ChainedBeanQueryAdapter deregister(BeanQueryAdapter c) {
+		if (!list.contains(c)){
+			return this;
+		} else {
+			ArrayList<BeanQueryAdapter> newList = new ArrayList<>();
+			newList.addAll(list);
+			newList.remove(c);
+
+			return new ChainedBeanQueryAdapter(newList);
+		}
+	}
+
+
+	/**
+	 * Return 0 as not used by this Chained adapter.
+	 */
+	public int getExecutionOrder() {
+		return 0;
+	}
+
+	/**
+	 * Return false as only individual adapters are registered.
+	 */
+	public boolean isRegisterFor(Class<?> cls) {
+		return false;
+	}
+
+	public void preQuery(BeanQueryRequest<?> request) {
+
+    for (BeanQueryAdapter aChain : chain) {
+      aChain.preQuery(request);
+    }
+	}
+	/**
+	 * Helper to order the BeanQueryAdapter's in a chain.
+	 */
+	private static class Sorter implements Comparator<BeanQueryAdapter> {
+
+		public int compare(BeanQueryAdapter o1, BeanQueryAdapter o2) {
+
+			int i1 = o1.getExecutionOrder() ;
+			int i2 = o2.getExecutionOrder() ;
+			return (i1<i2 ? -1 : (i1==i2 ? 0 : 1));
+		}
+
+	}
+}