[
https://issues.apache.org/jira/browse/APEXMALHAR-2010?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15203808#comment-15203808
]
ASF GitHub Bot commented on APEXMALHAR-2010:
--------------------------------------------
Github user chinmaykolhatkar commented on a diff in the pull request:
https://github.com/apache/incubator-apex-malhar/pull/209#discussion_r56785718
--- Diff: library/src/main/java/com/datatorrent/lib/util/PojoUtils.java ---
@@ -696,11 +662,97 @@ private static Object createSetter(Class<?>
pojoClass, String setterExpr, String
code = getSingleFieldSetterExpression(pojoClass, setterExpr,
exprClass);
}
+ return compileExpression(code, setterClass, new String[]
{PojoUtils.OBJECT, PojoUtils.VAL});
+ }
+
+ /**
+ * This method takes in expression, compiles the expression to provide a
executable form of expression.
+ * This method uses {@link
com.datatorrent.lib.expression.JavaExpressionParser} as expression parser.
+ *
+ * @param inputType Type of input object
+ * @param expr expression to be compiled.
+ * @param returnType Return type of the expression.
+ * @return Object of type {@link Expression} which can be directly
executed.
+ */
+ public static Expression createExpression(Class<?> inputType, String
expr, Class<?> returnType)
+ {
+ return createExpression(inputType, expr, returnType, null);
+ }
+
+ /**
+ * This method takes in expression, compiles the expression to provide a
executable form of expression.
+ * This methods also takes in list of classes and method which can be
imported statically in expression.
+ * <p/>
+ * This method uses {@link JavaExpressionParser} as expression parser.
+ *
+ * @param inputType Type of input object
+ * @param expr expression to be compiled.
+ * @param returnType Return type of the expression.
+ * @param defaultImports List of classes/method which will be statically
imported to expression compilation.
+ * @return Object of type {@link Expression} which can be directly
executed.
+ */
+ public static Expression createExpression(Class<?> inputType, String
expr, Class<?> returnType,
+ String[] defaultImports)
+ {
+ JavaExpressionParser javaExpressionParser = new JavaExpressionParser();
+ javaExpressionParser.setInputObjectPlaceholder("$", PojoUtils.OBJECT);
+
+ return createExpression(inputType, expr, returnType, defaultImports,
javaExpressionParser);
+ }
+
+ /**
+ * This method takes in expression, compiles the expression to provide a
executable form of expression.
+ * This methods also takes in list of classes and method which can be
imported statically in expression.
+ * <p/>
+ * Using this method one can override expression parser implementation.
+ *
+ * @param inputType Type of input object
+ * @param expr expression to be compiled.
+ * @param returnType Return type of the expression.
+ * @param defaultImports List of classes/method which will be statically
imported to expression compilation.
+ * @param parser Expression parser that should be used to parse
expression.
+ * @return Object of type {@link Expression} which can be directly
executed.
+ * @see {@link JavaExpressionParser} as a example.
+ */
+ public static Expression createExpression(Class<?> inputType, String
expr, Class<?> returnType,
+ String[] defaultImports, Expression.ExpressionParser parser)
+ {
+ String code = parser.convertToCompilableExpression(expr, inputType,
returnType);
+
+ return (Expression)compileExpression(code, Expression.class, new
String[] {PojoUtils.OBJECT}, defaultImports);
+ }
+
+ private static Object compileExpression(String code, Class<?> implClass,
String[] params)
+ {
+ return compileExpression(code, implClass, params, null);
+ }
+
+ private static Object compileExpression(String code, Class<?> implClass,
String[] params, String[] defaultImports)
+ {
+ List<String> imports = new LinkedList<>();
+ if (defaultImports != null && defaultImports.length != 0) {
+ for (String defaultImport : defaultImports) {
+ if (!defaultImport.startsWith("static")) {
--- End diff --
When adding a given import as static, that means the method will be
directly available in expression to be used. This way, the expression writer
can use similar syntax like excel functions.
> Add transform operator
> ----------------------
>
> Key: APEXMALHAR-2010
> URL: https://issues.apache.org/jira/browse/APEXMALHAR-2010
> Project: Apache Apex Malhar
> Issue Type: New Feature
> Components: algorithms
> Affects Versions: 3.4.0
> Reporter: Chinmay Kolhatkar
> Assignee: Chinmay Kolhatkar
>
> Add transform operator
> Details to be added soon once the mailing thread reaching conclusion:
> http://mail-archives.apache.org/mod_mbox/incubator-apex-dev/201603.mbox/%3CCABAipVZUdRGx5dS35bYPN46koLQU5gSLgbCeRH8aM_y9ANRU2w%40mail.gmail.com%3E
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