Allow custom SQL queries

Fix broken where string handling

src/com/roscopeco/ormdroid/Query.java

@@ -108,8 +108,9 @@ private static StringBuilder joinStrings(StringBuilder sb, String... strings) {
   }
 
   private final Class<T> mClass;
-  private final EntityMapping mEntityMapping; 
-  private String sqlCache, sqlCache1;
+  private final EntityMapping mEntityMapping;
+  private String customSql;
+  private String sqlCache, sqlCache1, whereCache;
   private SQLExpression whereExpr;
   private String[] orderByColumns;
   private int limit = -1;
@@ -154,38 +155,84 @@ public static SQLExpression or(SQLExpression... operands) {
     return new LogicalExpr("OR", operands);
   }
 
+  /**
+   * Set this query to execute the given custom SQL. This SQL must have proper
+   * syntax, and will be appended after the "SELECT * FROM sometable " generated
+   * by the Query itself.
+   * 
+   * Note that when using this method, you will no longer be able to use the
+   * other methods to set query parameters (e.g. {@link #where(SQLExpression)}
+   * and {@link #limit(int)}).
+   */
+  public Query<T> sql(String sql) {
+    sqlCache = null;
+    sqlCache1 = null;
+    whereCache = null;
+    whereExpr = null;
+    orderByColumns = null;
+    limit = -1;
+    customSql = sql;
+    return this;
+  }
+
   public Query<T> where(SQLExpression expr) {
+    if (customSql != null) {
+      throw new IllegalStateException("Cannot change query parameters on custom SQL Query");
+    }
+
     sqlCache = null;
     sqlCache1 = null;
+    whereCache = null;
     whereExpr = expr;
     return this;    
   }
 
   public Query<T> where(String sql) {
-    sqlCache = sql;
-    sqlCache1 = sql;
+    if (customSql != null) {
+      throw new IllegalStateException("Cannot change query parameters on custom SQL Query");
+    }
+
+    sqlCache = null;
+    sqlCache1 = null;
+    whereCache = sql;
     whereExpr = null;
     return this;    
   }
 
   public Query<T> orderBy(String... columns) {
+    if (customSql != null) {
+      throw new IllegalStateException("Cannot change query parameters on custom SQL Query");
+    }
+
     sqlCache = null;
     sqlCache1 = null;
     orderByColumns = columns;
     return this;
   }
 
   public Query<T> limit(int limit) {
+    if (customSql != null) {
+      throw new IllegalStateException("Cannot change query parameters on custom SQL Query");
+    }
+
     sqlCache = null;
     sqlCache1 = null;
     this.limit = limit;
     return this;
   }
 
   private String generate(int limit) {
+    if (customSql != null) {
+      return customSql;
+    }
+
     StringBuilder sb = new StringBuilder().append("SELECT * FROM ").append(mEntityMapping.mTableName);
-    if (whereExpr != null) {
-      sb.append(" WHERE ").append(whereExpr.generate());
+    if (whereCache != null) {
+      sb.append(" WHERE ").append(whereCache);      
+    } else {
+      if (whereExpr != null) {
+        sb.append(" WHERE ").append(whereCache = whereExpr.generate());
+      }
     }
     if (orderByColumns != null && orderByColumns.length > 0) {
       joinStrings(sb.append(" ORDER BY "), orderByColumns);