#919 - io.ebean package initial

src/main/java/io/ebeaninternal/server/querydefn/OrmQueryDetailParser.java

@@ -0,0 +1,107 @@
+package io.ebeaninternal.server.querydefn;
+
+import javax.persistence.PersistenceException;
+
+/**
+ * Parses a Object relational query statement into a OrmQueryDetail and OrmQueryAttributes.
+ * <p>
+ * The reason they are split into detail and attributes is that the AutoTune feature is used to
+ * replace the OrmQueryDetail leaving the attributes unchanged.
+ * </p>
+ */
+public class OrmQueryDetailParser {
+
+  private final OrmQueryDetail detail = new OrmQueryDetail();
+
+  private final SimpleTextParser parser;
+
+  public OrmQueryDetailParser(String oql) {
+    this.parser = new SimpleTextParser(oql);
+  }
+
+  public OrmQueryDetail parse() throws PersistenceException {
+
+    if (parser.isEmpty()) return detail;
+
+    parser.nextWord();
+    processInitial();
+    return detail;
+  }
+
+  private void processInitial() {
+    if (parser.isMatch("select")) {
+      readSelect();
+    } else if (parser.isMatch("find")) {
+      OrmQueryProperties props = readFindFetch();
+      detail.setBase(props);
+    } else {
+      process();
+    }
+    while (!parser.isFinished()) {
+      process();
+    }
+  }
+
+  private boolean isFetch() {
+    return parser.isMatch("fetch") || parser.isMatch("join");
+  }
+
+  private void process() {
+    if (isFetch()) {
+      detail.fetch(readFindFetch());
+    } else {
+      throw new PersistenceException("Query expected 'fetch', 'where','order by' or 'limit' keyword but got ["
+        + parser.getWord() + "] \r " + parser.getOql());
+    }
+  }
+
+  private void readSelect() {
+    String props = parser.nextWord();
+    if (props.startsWith("(")) {
+      props = props.substring(1, props.length() - 1);
+      OrmQueryProperties base = new OrmQueryProperties(null, props);
+      detail.setBase(base);
+      parser.nextWord();
+    } else {
+      process();
+    }
+  }
+
+  private OrmQueryProperties readFindFetch() {
+
+    boolean readAlias = false;
+
+    String props = null;
+    String path = parser.nextWord();
+    String token;
+    while ((token = parser.nextWord()) != null) {
+      if (!readAlias && parser.isMatch("as")) {
+        // next token is alias
+        parser.nextWord();
+        readAlias = true;
+
+      } else if ('(' == token.charAt(0)) {
+        props = token;
+        parser.nextWord();
+        break;
+
+      } else if (isFindFetchEnd()) {
+        break;
+
+      } else if (!readAlias) {
+        readAlias = true;
+
+      } else {
+        throw new PersistenceException("Expected (props) or new 'fetch' 'where' but got " + token);
+      }
+    }
+    if (props != null) {
+      props = props.substring(1, props.length() - 1);
+    }
+    return new OrmQueryProperties(path, props);
+  }
+
+  private boolean isFindFetchEnd() {
+    return isFetch() || parser.isMatch("where") || parser.isMatch("order", "by");
+  }
+}