#1211 - ENH: Support L2 cache complex natural keys include findList() queries

src/main/java/io/ebeaninternal/api/NaturalKeyQueryData.java

@@ -0,0 +1,170 @@
+package io.ebeaninternal.api;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Collects the data for processing the natural key cache processing.
+ */
+public class NaturalKeyQueryData<T> {
+
+  private final String[] naturalKey;
+
+  private Collection<?> inValues;
+
+  private String inProperty;
+
+  private List<NaturalKeyEq> eqList;
+
+  private NaturalKeySet set;
+
+  private int hitCount;
+
+  public NaturalKeyQueryData(String[] naturalKey) {
+    this.naturalKey = naturalKey;
+  }
+
+  private boolean matchProperty(String propName) {
+
+    for (String key : naturalKey) {
+      if (key.equals(propName)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  /**
+   * Match for IN expression. We only allow one IN clause.
+   */
+  public boolean matchIn(String propName, Collection<?> sourceValues) {
+    if (inProperty != null) {
+      // only 1 IN allowed (to project naturalIds)
+      return false;
+    }
+    if (matchProperty(propName)) {
+      this.inProperty = propName;
+      this.inValues = sourceValues;
+      return true;
+    }
+    return false;
+  }
+
+  /**
+   * Match for an EQ expression.
+   */
+  public boolean matchEq(String propName, Object bindValue) {
+    if (matchProperty(propName)) {
+      if (eqList == null) {
+        eqList = new ArrayList<>();
+      }
+      eqList.add(new NaturalKeyEq(propName, bindValue));
+      return true;
+    }
+    return false;
+  }
+
+  /**
+   * Build and return the set of natural keys we will use.
+   */
+  public NaturalKeySet buildKeys() {
+
+    if (!expressionCount() || !matchProperties()) {
+      return null;
+    }
+
+    this.set = new NaturalKeySet();
+    if (inValues == null) {
+      // only one - a findOne()
+      set.add(new NaturalKeyEntry(naturalKey, eqList));
+
+    } else {
+      // a findList() with an IN clause so we project
+      // for every IN value a natural key combination
+      for (Object inValue : inValues) {
+        set.add(new NaturalKeyEntry(naturalKey, eqList, inProperty, inValue));
+      }
+    }
+
+    return set;
+  }
+
+  /**
+   * Return true if the properties match the natural key properties.
+   */
+  private boolean matchProperties() {
+    if (naturalKey.length == 1) {
+      // simple single property case
+      if (inProperty != null) {
+        return inProperty.equals(naturalKey[0]);
+      } else {
+        return eqList.get(0).property.equals(naturalKey[0]);
+      }
+    }
+
+    // multiple properties case
+    Set<String> exprProps = new HashSet<>();
+    if (inProperty != null) {
+      exprProps.add(inProperty);
+    }
+    if (eqList != null) {
+      for (NaturalKeyEq eq : eqList) {
+        exprProps.add(eq.property);
+      }
+    }
+    if (exprProps.size() != naturalKey.length) {
+      return false;
+    }
+    for (String key : naturalKey) {
+      if (!exprProps.remove(key)) {
+        return false;
+      }
+    }
+
+    return exprProps.isEmpty();
+  }
+
+  /**
+   * Check that all the natural key properties are defined.
+   */
+  private boolean expressionCount() {
+
+    int defined = (inValues == null) ? 0 : 1;
+    defined += (eqList == null) ? 0 : eqList.size();
+    return defined == naturalKey.length;
+  }
+
+  /**
+   * Return the number of entries in the IN clause left remaining (to hit the DB with).
+   */
+  public boolean allHits() {
+    return hitCount > 0
+      && hitCount == set.size()
+      && (inValues == null || inValues.isEmpty());
+  }
+
+  /**
+   * Adjust the IN clause removing the hit entry.
+   */
+  public List<T> removeHits(BeanCacheResult<T> cacheResult) {
+
+    List<BeanCacheResult.Entry<T>> hits = cacheResult.hits();
+    this.hitCount = hits.size();
+
+    List<T> beans = new ArrayList<>(hitCount);
+
+    for (BeanCacheResult.Entry<T> hit : hits) {
+      if (inValues != null) {
+        Object naturalKey = hit.getKey();
+        Object inValue = set.getInValue(naturalKey);
+        inValues.remove(inValue);
+      }
+      beans.add(hit.getBean());
+    }
+
+    return beans;
+  }
+}