$filter $top $skip $count logic

implemented eq and ne (case-sensitive) for String values, and eq, ne, gt ,ge , lt, le  on the Timestamp field

src/main/java/org/reso/service/data/GenericEntityCollectionProcessor.java

@@ -18,7 +18,10 @@ import org.apache.olingo.server.api.serializer.SerializerResult;
 import org.apache.olingo.server.api.uri.UriInfo;
 import org.apache.olingo.server.api.uri.UriResource;
 import org.apache.olingo.server.api.uri.UriResourceEntitySet;
+import org.apache.olingo.server.api.uri.queryoption.*;
+import org.apache.olingo.server.api.uri.queryoption.expression.Expression;
 import org.reso.service.data.meta.FieldInfo;
+import org.reso.service.data.meta.FilterExpressionVisitor;
 import org.reso.service.data.meta.ResourceInfo;
 import org.reso.service.edmprovider.RESOedmProvider;
 import org.slf4j.Logger;
@@ -30,6 +33,7 @@ import java.net.URISyntaxException;
 import java.sql.*;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 
 public class GenericEntityCollectionProcessor implements EntityCollectionProcessor
@@ -82,9 +86,18 @@ public class GenericEntityCollectionProcessor implements EntityCollectionProcess
       UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths.get(0); // in our example, the first segment is the EntitySet
       EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();
 
+      boolean isCount = false;
+      CountOption countOption = uriInfo.getCountOption();
+      if (countOption != null) {
+         isCount = countOption.getValue();
+         if (isCount){
+            LOG.info("Count str:"+countOption.getText() );
+         }
+      }
+
       // 2nd: fetch the data from backend for this requested EntitySetName
       // it has to be delivered as EntitySet object
-      EntityCollection entitySet = getData(edmEntitySet);
+      EntityCollection entitySet = getData(edmEntitySet, uriInfo, isCount);
 
       // 3rd: create a serializer based on the requested format (json)
       try
@@ -105,7 +118,19 @@ public class GenericEntityCollectionProcessor implements EntityCollectionProcess
       ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).build();
 
       final String id = request.getRawBaseUri() + "/" + edmEntitySet.getName();
-      EntityCollectionSerializerOptions opts = EntityCollectionSerializerOptions.with().id(id).contextURL(contextUrl).build();
+      EntityCollectionSerializerOptions opts = null;
+      if (isCount)  // If there's a $count=true in the query string, we need to have a different formatting options.
+      {
+         opts = EntityCollectionSerializerOptions.with()
+                  .contextURL(contextUrl)
+                  .id(id)
+                  .count(countOption)
+                  .build();
+      }
+      else
+      {
+         opts = EntityCollectionSerializerOptions.with().id(id).contextURL(contextUrl).build();
+      }
       SerializerResult serializerResult = serializer.entityCollection(serviceMetadata, edmEntityType, entitySet, opts);
       InputStream serializedContent = serializerResult.getContent();
 
@@ -116,20 +141,85 @@ public class GenericEntityCollectionProcessor implements EntityCollectionProcess
    }
 
 
-   protected EntityCollection getData(EdmEntitySet edmEntitySet){
+   protected EntityCollection getData(EdmEntitySet edmEntitySet, UriInfo uriInfo, boolean isCount) throws ODataApplicationException {
       ArrayList<FieldInfo> fields = this.resourceInfo.getFieldList();
 
-      EntityCollection lookupsCollection = new EntityCollection();
+      EntityCollection entCollection = new EntityCollection();
 
-      List<Entity> productList = lookupsCollection.getEntities();
+      List<Entity> productList = entCollection.getEntities();
 
       Map<String, String> properties = System.getenv();
 
       try {
+
+         FilterOption filter = uriInfo.getFilterOption();
+         String sqlCriteria = null;
+         if (filter!=null)
+         {
+            sqlCriteria = filter.getExpression().accept(new FilterExpressionVisitor(this.resourceInfo));
+         }
+
          // Statements allow to issue SQL queries to the database
          Statement statement = connect.createStatement();
          // Result set get the result of the SQL query
-         ResultSet resultSet = statement.executeQuery("select * from "+this.resourceInfo.getTableName());
+         String queryString = null;
+
+         // Logic for $count
+         if (isCount)
+         {
+            queryString = "select count(*) AS rowcount from " + this.resourceInfo.getTableName();
+         }
+         else
+         {
+            queryString = "select * from " + this.resourceInfo.getTableName();
+         }
+         if (null!=sqlCriteria && sqlCriteria.length()>0)
+         {
+            queryString = queryString + " WHERE " + sqlCriteria;
+         }
+
+         // Logic for $top
+         TopOption topOption = uriInfo.getTopOption();
+         if (topOption != null) {
+            int topNumber = topOption.getValue();
+            if (topNumber >= 0)
+            {
+               // Logic for $skip
+               SkipOption skipOption = uriInfo.getSkipOption();
+               if (skipOption != null)
+               {
+                  int skipNumber = skipOption.getValue();
+                  if (skipNumber >= 0)
+                  {
+                     queryString = queryString + " LIMIT "+skipNumber+", "+topNumber;
+                  }
+                  else
+                  {
+                     throw new ODataApplicationException("Invalid value for $skip", HttpStatusCode.BAD_REQUEST.getStatusCode(), Locale.ROOT);
+                  }
+               }
+               else
+               {
+                  queryString = queryString + " LIMIT " + topNumber;
+               }
+            }
+            else
+            {
+               throw new ODataApplicationException("Invalid value for $top", HttpStatusCode.BAD_REQUEST.getStatusCode(), Locale.ROOT);
+            }
+         }
+
+         LOG.info("SQL Query: "+queryString);
+         ResultSet resultSet = statement.executeQuery(queryString);
+
+         // special return logic for $count
+         if (isCount && resultSet.next())
+         {
+            int size = resultSet.getInt("rowcount");
+            LOG.info("Size = "+size);
+            entCollection.setCount(size);
+            return entCollection;
+         }
 
          String primaryFieldName = fields.get(0).getFieldName();
 
@@ -149,7 +239,7 @@ public class GenericEntityCollectionProcessor implements EntityCollectionProcess
                }
                else if (field.getType().equals(EdmPrimitiveTypeKind.DateTimeOffset.getFullQualifiedName()))
                {
-                  value = resultSet.getDate(fieldName);
+                  value = resultSet.getTimestamp(fieldName);
                }
                else
                {
@@ -167,10 +257,10 @@ public class GenericEntityCollectionProcessor implements EntityCollectionProcess
 
       } catch (Exception e) {
             LOG.error("Server Error occurred in reading "+this.resourceInfo.getResourceName(), e);
-         return lookupsCollection;
+         return entCollection;
       }
 
-      return lookupsCollection;
+      return entCollection;
    }
 
    private URI createId(String entitySetName, Object id) {

src/main/java/org/reso/service/data/meta/FilterExpressionVisitor.java

@@ -0,0 +1,172 @@
+package org.reso.service.data.meta;
+
+import org.apache.olingo.commons.api.edm.EdmEnumType;
+import org.apache.olingo.commons.api.edm.EdmPrimitiveTypeKind;
+import org.apache.olingo.commons.api.edm.EdmType;
+import org.apache.olingo.commons.api.http.HttpStatusCode;
+import org.apache.olingo.server.api.ODataApplicationException;
+import org.apache.olingo.server.api.uri.UriResource;
+import org.apache.olingo.server.api.uri.UriResourcePrimitiveProperty;
+import org.apache.olingo.server.api.uri.queryoption.expression.BinaryOperatorKind;
+import org.apache.olingo.server.api.uri.queryoption.expression.Expression;
+import org.apache.olingo.server.api.uri.queryoption.expression.ExpressionVisitException;
+import org.apache.olingo.server.api.uri.queryoption.expression.ExpressionVisitor;
+import org.apache.olingo.server.api.uri.queryoption.expression.Literal;
+import org.apache.olingo.server.api.uri.queryoption.expression.Member;
+import org.apache.olingo.server.api.uri.queryoption.expression.MethodKind;
+import org.apache.olingo.server.api.uri.queryoption.expression.UnaryOperatorKind;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.text.SimpleDateFormat;
+import java.time.format.DateTimeFormatter;
+import java.time.temporal.TemporalAccessor;
+import java.util.*;
+
+/**
+ * $filter
+ */
+public class FilterExpressionVisitor implements ExpressionVisitor<String> {
+   private static final Logger                          LOG              = LoggerFactory.getLogger(FilterExpressionVisitor.class);
+   private static final Map<BinaryOperatorKind, String> BINARY_OPERATORS = new HashMap<BinaryOperatorKind, String>() {{
+      put(BinaryOperatorKind.ADD, " + ");
+      put(BinaryOperatorKind.AND, " AND ");
+      put(BinaryOperatorKind.DIV, " / ");
+      put(BinaryOperatorKind.EQ, " = ");
+      put(BinaryOperatorKind.GE, " >= ");
+      put(BinaryOperatorKind.GT, " > ");
+      put(BinaryOperatorKind.LE, " <= ");
+      put(BinaryOperatorKind.LT, " < ");
+      put(BinaryOperatorKind.MOD, " % ");
+      put(BinaryOperatorKind.MUL, " * ");
+      put(BinaryOperatorKind.NE, " <> ");
+      put(BinaryOperatorKind.OR, " OR ");
+      put(BinaryOperatorKind.SUB, " - ");
+   }};
+
+   private String entityAlias;
+   private ResourceInfo resourceInfo;
+
+   public FilterExpressionVisitor(ResourceInfo resourceInfo) {
+      this.entityAlias = resourceInfo.getTableName();
+      this.resourceInfo = resourceInfo;
+   }
+
+   @Override
+   public String visitBinaryOperator(BinaryOperatorKind operator, String left, String right)
+            throws ExpressionVisitException, ODataApplicationException {
+      String strOperator = BINARY_OPERATORS.get(operator);
+
+      if (strOperator == null) {
+         throw new ODataApplicationException("Unsupported binary operation: " + operator.name(),
+                                             operator == BinaryOperatorKind.HAS ?
+                                                      HttpStatusCode.NOT_IMPLEMENTED.getStatusCode() :
+                                                      HttpStatusCode.BAD_REQUEST.getStatusCode(), Locale.ENGLISH);
+      }
+      return left + strOperator + right;
+   }
+
+   @Override
+   public String visitUnaryOperator(UnaryOperatorKind operator, String operand)
+            throws ExpressionVisitException, ODataApplicationException {
+      switch (operator) {
+         case NOT:
+            return "NOT " + operand;
+         case MINUS:
+            return "-" + operand;
+      }
+      throw new ODataApplicationException("Wrong unary operator: " + operator,
+                                          HttpStatusCode.BAD_REQUEST.getStatusCode(), Locale.ENGLISH);
+   }
+
+   @Override
+   public String visitMethodCall(MethodKind methodCall, List<String> parameters)
+            throws ExpressionVisitException, ODataApplicationException {
+      if (parameters.isEmpty() && methodCall.equals(MethodKind.NOW)) {
+         return "CURRENT_DATE";
+      }
+      String firsEntityParam = parameters.get(0);
+      switch (methodCall) {
+         case CONTAINS:
+            return firsEntityParam + " LIKE '%" + extractFromStringValue(parameters.get(1)) + "%'";
+         case STARTSWITH:
+            return firsEntityParam + " LIKE '" + extractFromStringValue(parameters.get(1)) + "%'";
+         case ENDSWITH:
+            return firsEntityParam + " LIKE '%" + extractFromStringValue(parameters.get(1));
+         case DAY:
+            return "DAY(" + firsEntityParam + ")";
+         case MONTH:
+            return "MONTH(" + firsEntityParam + ")";
+         case YEAR:
+            return "YEAR(" + firsEntityParam + ")";
+      }
+      throw new ODataApplicationException("Method call " + methodCall + " not implemented",
+                                          HttpStatusCode.NOT_IMPLEMENTED.getStatusCode(), Locale.ENGLISH);
+   }
+
+   @Override
+   public String visitLiteral(Literal literal) throws ExpressionVisitException, ODataApplicationException {
+      String literalAsString = literal.getText();
+      if (literal.getType() == null) {
+         literalAsString = "NULL";
+      }
+      if (literal.getType().getFullQualifiedName().equals( EdmPrimitiveTypeKind.DateTimeOffset.getFullQualifiedName() ) )
+      {
+         return "'"+literalAsString+"'";
+      }
+
+      return literalAsString;
+   }
+
+   @Override
+   public String visitMember(Member member) throws ExpressionVisitException, ODataApplicationException {
+      List<UriResource> resources = member.getResourcePath().getUriResourceParts();
+
+      UriResource first = resources.get(0);
+
+      // TODO: Enum and ComplexType; joins
+      if (resources.size() == 1 && first instanceof UriResourcePrimitiveProperty) {
+         UriResourcePrimitiveProperty primitiveProperty = (UriResourcePrimitiveProperty) first;
+         return entityAlias + "." + primitiveProperty.getProperty().getName();
+      } else {
+         throw new ODataApplicationException("Only primitive properties are implemented in filter expressions",
+                                             HttpStatusCode.NOT_IMPLEMENTED.getStatusCode(), Locale.ENGLISH);
+      }
+   }
+
+   @Override
+   public String visitEnum(EdmEnumType type, List<String> enumValues)
+            throws ExpressionVisitException, ODataApplicationException {
+      throw new ODataApplicationException("Enums are not implemented", HttpStatusCode.NOT_IMPLEMENTED.getStatusCode(),
+                                          Locale.ENGLISH);
+   }
+
+   @Override
+   public String visitLambdaExpression(String lambdaFunction, String lambdaVariable, Expression expression)
+            throws ExpressionVisitException, ODataApplicationException {
+      throw new ODataApplicationException("Lambda expressions are not implemented",
+                                          HttpStatusCode.NOT_IMPLEMENTED.getStatusCode(), Locale.ENGLISH);
+   }
+
+   @Override
+   public String visitAlias(String aliasName) throws ExpressionVisitException, ODataApplicationException {
+      throw new ODataApplicationException("Aliases are not implemented",
+                                          HttpStatusCode.NOT_IMPLEMENTED.getStatusCode(), Locale.ENGLISH);
+   }
+
+   @Override
+   public String visitTypeLiteral(EdmType type) throws ExpressionVisitException, ODataApplicationException {
+      throw new ODataApplicationException("Type literals are not implemented",
+                                          HttpStatusCode.NOT_IMPLEMENTED.getStatusCode(), Locale.ENGLISH);
+   }
+
+   @Override
+   public String visitLambdaReference(String variableName) throws ExpressionVisitException, ODataApplicationException {
+      throw new ODataApplicationException("Lambda references are not implemented",
+                                          HttpStatusCode.NOT_IMPLEMENTED.getStatusCode(), Locale.ENGLISH);
+   }
+
+   private String extractFromStringValue(String val) {
+      return val.substring(1, val.length() - 1);
+   }
+}

src/main/java/org/reso/service/security/providers/BasicAuthProvider.java

@@ -23,7 +23,7 @@ public class BasicAuthProvider implements Provider
    private static final Logger LOG = LoggerFactory.getLogger(BasicAuthProvider.class);
 
    /**
-    * A simple BEARER Token Auth with a set token.
+    * A simple BASIC Auth with static username and password.
     * @param req The HTTP Request object from the servlet.
     * @return true if authorized, false otherwise.
     */
@@ -38,7 +38,6 @@ public class BasicAuthProvider implements Provider
          if (authResp!=null && authResp.length()>0)
          {
             String[] parts = authResp.split(BasicAuthProvider.AUTH_SPACE);
-            LOG.info("header:"+authResp);
             if (parts[0].equals(BasicAuthProvider.BASIC_STR) && parts.length==2)
             {
                String base64decoded = new String(Base64.getDecoder().decode(parts[1]));
@@ -48,8 +47,6 @@ public class BasicAuthProvider implements Provider
                {
                   String username = parts[0];
                   String password = parts[1];
-                  LOG.info("User:"+username);
-                  LOG.info("Pass:"+password);
 
                   if (username.equals(AUTH_USER) && password.equals(AUTH_PASSWORD))
                   {

src/main/java/org/reso/service/security/providers/BearerAuthProvider.java

@@ -20,7 +20,7 @@ public class BearerAuthProvider implements Provider
    private static final Logger LOG = LoggerFactory.getLogger(BearerAuthProvider.class);
 
    /**
-    * A simple BASIC Auth with static username and password.  Purely for testing purposes.
+    * A simple BEARER Token Auth with a set token.
     * @param req The HTTP Request object from the servlet.
     * @return true if authorized, false otherwise.
     */

src/main/java/org/reso/service/servlet/RESOservlet.java

@@ -49,7 +49,7 @@ public class RESOservlet extends HttpServlet
       }
 
       this.validator = new Validator();
-//      this.validator.addProvider(new BasicAuthProvider());
+//      this.validator.addProvider(new BasicAuthProvider());  // We're using this for the token auth.  Only use here for easy browser testing.
       this.validator.addProvider(new BearerAuthProvider());
 
       String mysqlHost = env.get("SQL_HOST");