Add emptyList/emptyMap functions #477

fizz-core/src/main/java/com/fizzgate/fizz/function/CommonFunc.java

@@ -18,7 +18,10 @@
 package com.fizzgate.fizz.function;
 
 import java.lang.reflect.Array;
+import java.util.ArrayList;
 import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import org.apache.commons.lang3.StringUtils;
@@ -65,6 +68,8 @@ public class CommonFunc implements IFunc {
 		FuncExecutor.register(NAME_SPACE_PREFIX + "common.and", this);
 		FuncExecutor.register(NAME_SPACE_PREFIX + "common.or", this);
 		FuncExecutor.register(NAME_SPACE_PREFIX + "common.not", this);
+		FuncExecutor.register(NAME_SPACE_PREFIX + "common.emptyMap", this);
+		FuncExecutor.register(NAME_SPACE_PREFIX + "common.emptyList", this);
 	}
 
 	/**
@@ -174,4 +179,22 @@ public class CommonFunc implements IFunc {
 		return !(obj == null ? false : obj);
 	}
 	
+	/**
+	 * Return an empty map
+	 * 
+	 * @return
+	 */
+	public Map<String, Object> emptyMap() {
+		return new HashMap<>();
+	}
+	
+	/**
+	 * Return an empty list
+	 * 
+	 * @return
+	 */
+	public List<Map<String, Object>> emptyList() {
+		return new ArrayList<>();
+	}
+	
 }

fizz-core/src/main/java/com/fizzgate/fizz/function/FuncExecutor.java

@@ -312,6 +312,26 @@ public class FuncExecutor {
 				argsStrContainer = this.trimArgStr(argsStrContainer, 5, isVarArgs, paramTypes.length, funcExpression);
 				argsStr = argsStrContainer.getArgsStr();
 				i = argsStrContainer.getIndex();
+			} else if (argsStr.matches("^\\[\\]\\s*,.*") || argsStr.matches("^\\[\\]\\s*\\).*")) { // []
+				if (isVarArgs && i == paramTypes.length - 1) {
+					varArgs.add(new ArrayList());
+					args[i] = varArgs.toArray(new ArrayList[varArgs.size()]);
+				} else {
+					args[i] = new ArrayList();
+				}
+				argsStrContainer = this.trimArgStr(argsStrContainer, 2, isVarArgs, paramTypes.length, funcExpression);
+				argsStr = argsStrContainer.getArgsStr();
+				i = argsStrContainer.getIndex();
+			} else if (argsStr.matches("^\\{\\}\\s*,.*") || argsStr.matches("^\\{\\}\\s*\\).*")) { // {}
+				if (isVarArgs && i == paramTypes.length - 1) {
+					varArgs.add(new HashMap());
+					args[i] = varArgs.toArray(new HashMap[varArgs.size()]);
+				} else {
+					args[i] = new HashMap();
+				}
+				argsStrContainer = this.trimArgStr(argsStrContainer, 2, isVarArgs, paramTypes.length, funcExpression);
+				argsStr = argsStrContainer.getArgsStr();
+				i = argsStrContainer.getIndex();
 			} else if (argsStr.startsWith("{")) { // reference value
 				int pos = argsStr.indexOf("}", 1);
 				if (pos != -1) {

fizz-core/src/main/java/com/fizzgate/fizz/function/ListFunc.java

@@ -62,6 +62,7 @@ public class ListFunc implements IFunc {
 		FuncExecutor.register(NAME_SPACE_PREFIX + "list.join", this);
 		FuncExecutor.register(NAME_SPACE_PREFIX + "list.rename", this);
 		FuncExecutor.register(NAME_SPACE_PREFIX + "list.removeFields", this);
+		FuncExecutor.register(NAME_SPACE_PREFIX + "list.emptyList", this);
 	}
 
 	/**
@@ -227,5 +228,14 @@ public class ListFunc implements IFunc {
 		}
 		return data;
 	}
+	
+	/**
+	 * Return an empty list
+	 * 
+	 * @return
+	 */
+	public List<Map<String, Object>> emptyList() {
+		return new ArrayList<>();
+	}
 
 }

fizz-core/src/test/java/com/fizzgate/fizz/function/CommonFuncTests.java

@@ -16,6 +16,7 @@
  */
 package com.fizzgate.fizz.function;
 
+import static org.junit.Assert.assertNull;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.ArrayList;
@@ -116,6 +117,46 @@ class CommonFuncTests {
 		assertEquals(true, result);
 	}
 	
+	@Test
+	void testIif6() {
+		// test [] 
+		String funcExpression = "fn.common.iif(false, \"abc\", [])";
+		List result = (List)FuncExecutor.getInstance().exec(null, funcExpression);
+		assertEquals(true, result.size() == 0);
+	}
+	
+	@Test
+	void testIif7() {
+		// test {}
+		String funcExpression = "fn.common.iif(false, \"abc\", {})";
+		Map result = (Map)FuncExecutor.getInstance().exec(null, funcExpression);
+		assertEquals(true, result.size() == 0);
+	}
+	
+	@Test
+	void testIif8() {
+		// test [] 
+		String funcExpression = "fn.common.iif(false, \"abc\", fn.common.emptyList())";
+		List result = (List)FuncExecutor.getInstance().exec(null, funcExpression);
+		assertEquals(true, result.size() == 0);
+	}
+	
+	@Test
+	void testIif9() {
+		// test {}
+		String funcExpression = "fn.common.iif(false, \"abc\", fn.common.emptyMap())";
+		Map result = (Map)FuncExecutor.getInstance().exec(null, funcExpression);
+		assertEquals(true, result.size() == 0);
+	}
+	
+	@Test
+	void testIif10() {
+		// test null
+		String funcExpression = "fn.common.iif(false, \"abc\", null)";
+		Map result = (Map)FuncExecutor.getInstance().exec(null, funcExpression);
+		assertNull(result);
+	}
+	
 	@Test
 	void testEquals() {
 		String funcExpression = "fn.common.equals(\"abc\", true)";

fizz-core/src/test/java/com/fizzgate/fizz/function/ListFuncTests.java

@@ -106,6 +106,29 @@ class ListFuncTests {
 		assertEquals("a2", ((Map<String, Object>) result.get(1)).get("a").toString());
 		assertEquals("a4", ((Map<String, Object>) result.get(3)).get("a").toString());
 	}
+	
+	@Test
+	void testMerge2() {
+		List<Object> subList1 = new ArrayList<>();
+		subList1.add(createRecord("a", "a1"));
+		subList1.add(createRecord("a", "a2"));
+		subList1.add(createRecord("a", "a3"));
+
+		List<Object> subList2 = new ArrayList<>();
+		subList2.add(createRecord("a", "a4"));
+		subList2.add(createRecord("a", "a5"));
+		subList2.add(createRecord("a", "a6"));
+
+		ONode ctxNode = ONode.load(new HashMap());
+		PathMapping.setByPath(ctxNode, "test.data1", subList1, true);
+		PathMapping.setByPath(ctxNode, "test.data2", subList2, true);
+
+		String funcExpression = "fn.list.merge({test.data1}, [] , {test.data2})";
+		List<Object> result = (List<Object>) FuncExecutor.getInstance().exec(ctxNode, funcExpression);
+		assertEquals(6, result.size());
+		assertEquals("a2", ((Map<String, Object>) result.get(1)).get("a").toString());
+		assertEquals("a4", ((Map<String, Object>) result.get(3)).get("a").toString());
+	}
 
 	@Test
 	void testExtract() {