コード例 #1
0
ファイル: ExpressionTest.java プロジェクト: ergatech/linq4j
  public void testLambdaCallsBinaryOp() {
    // A parameter for the lambda expression.
    ParameterExpression paramExpr = Expressions.parameter(Integer.TYPE, "arg");

    // This expression represents a lambda expression
    // that adds 1 to the parameter value.
    FunctionExpression lambdaExpr =
        Expressions.lambda(
            Expressions.add(paramExpr, Expressions.constant(2)), Arrays.asList(paramExpr));

    // Print out the expression.
    String s = Expressions.toString(lambdaExpr);
    assertEquals(
        "new net.hydromatic.linq4j.function.Function1() {\n"
            + "  public int apply(Integer arg) {\n"
            + "    return arg + 2;\n"
            + "  }\n"
            + "  public Object apply(Object arg) {\n"
            + "    return apply(\n"
            + "      (Integer) arg);\n"
            + "  }\n"
            + "}\n",
        s);

    // Compile and run the lambda expression.
    // The value of the parameter is 1.
    int n = (Integer) lambdaExpr.compile().dynamicInvoke(1);

    // This code example produces the following output:
    //
    // arg => (arg +2)
    // 3
    assertEquals(3, n);
  }
コード例 #2
0
ファイル: ExpressionTest.java プロジェクト: ergatech/linq4j
  public void testLambdaCallsTwoArgMethod() throws NoSuchMethodException {
    // A parameter for the lambda expression.
    ParameterExpression paramS = Expressions.parameter(String.class, "s");
    ParameterExpression paramBegin = Expressions.parameter(Integer.TYPE, "begin");
    ParameterExpression paramEnd = Expressions.parameter(Integer.TYPE, "end");

    // This expression represents a lambda expression
    // that adds 1 to the parameter value.
    FunctionExpression lambdaExpr =
        Expressions.lambda(
            Expressions.call(
                paramS,
                String.class.getMethod("substring", Integer.TYPE, Integer.TYPE),
                paramBegin,
                paramEnd),
            paramS,
            paramBegin,
            paramEnd);

    // Compile and run the lambda expression.
    String s = (String) lambdaExpr.compile().dynamicInvoke("hello world", 3, 7);

    assertEquals("lo w", s);
  }