#919 - io.ebean package initial

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

@@ -0,0 +1,96 @@
+package io.ebeaninternal.server.deploy;
+
+import io.ebeaninternal.server.deploy.meta.DeployBeanDescriptor;
+import io.ebeaninternal.server.deploy.meta.DeployBeanProperty;
+import io.ebeaninternal.server.deploy.meta.DeployBeanPropertyAssocMany;
+import io.ebeaninternal.server.deploy.meta.DeployBeanPropertyAssocOne;
+
+class DetermineAggPath {
+
+  /**
+   * Return the many path for the given aggregation formula.
+   */
+  static String manyPath(String aggregation, DeployBeanDescriptor<?> desc) {
+    DetermineAggPath.Path path = paths(aggregation);
+    return path.getManyPath(0, desc);
+  }
+
+  static Path paths(String aggregation) {
+    String aggPath = path(aggregation);
+    return new Path(aggPath.split("\\."), aggregation);
+  }
+
+  /**
+   * Parse and return the full path for the aggregation.
+   */
+  static String path(String aggregation) {
+
+    // aggregations always have a form of sum(), avg(), max(), count() etc
+    // so find the first open bracket
+    int start = aggregation.indexOf('(');
+    if (start == -1) {
+      throw new IllegalArgumentException("Aggregation formula ["+aggregation+"] is expected to have a '(' ?");
+    }
+    for (int i = start + 1; i< aggregation.length(); i++) {
+      char ch = aggregation.charAt(i);
+      if (!isNamePart(ch)) {
+        return aggregation.substring(start + 1, i);
+      }
+    }
+
+    throw new IllegalArgumentException("Could not find path in aggregation formula ["+aggregation+"]");
+  }
+
+  private static boolean isNamePart(char ch) {
+    return ch == '.' || Character.isJavaIdentifierPart(ch);
+  }
+
+
+  /**
+   * Helper class holding aggregation path segments.
+   */
+  static class Path {
+
+    final String aggregation;
+    final String[] paths;
+
+    Path(String[] paths, String aggregation) {
+      this.paths = paths;
+      this.aggregation = aggregation;
+    }
+
+    int length() {
+      return paths.length;
+    }
+
+    String path(int pos) {
+      if (pos == 0) {
+        return paths[0];
+      } else {
+        StringBuilder sb = new StringBuilder();
+        for (int i = 0; i < pos; i++) {
+          if (i > 0) {
+            sb.append(".");
+          }
+          sb.append(paths[i]);
+        }
+        return sb.toString();
+      }
+    }
+
+    String getManyPath(int pos, DeployBeanDescriptor<?> desc) {
+
+      String path = paths[pos];
+      DeployBeanProperty details = desc.getBeanProperty(path);
+      if (details instanceof DeployBeanPropertyAssocMany<?>) {
+        return path(pos);
+
+      } else if (details instanceof DeployBeanPropertyAssocOne<?>) {
+        DeployBeanPropertyAssocOne<?> one = (DeployBeanPropertyAssocOne<?>)details;
+        DeployBeanDescriptor<?> targetDesc = one.getTargetDeploy();
+        return getManyPath(pos + 1, targetDesc);
+      }
+      throw new IllegalArgumentException("Can not find path to many in aggregation formula ["+aggregation+"]");
+    }
+  }
+}