Flow Control - Java for COBOL Programmers - page 169

This basic control flow statement will evaluate condition , and if true , the first
block of code will execute; if false , the second block will be performed. As is the
case in COBOL, the second code block (the else condition) is optional.
if (inputMsg.equals ("Any Text")) {
...
}
else {
...
}
condition can be any Java expression that returns a boolean. The result of that ex-
pression is evaluated.
if (myErrorMsg.msgText.equals ("Any Text")) {
...
}
condition must be a boolean expression, that is, one that evaluates to either true or
false. In the example, the equals() method returns a true or false boolean, so it is a
good candidate for inclusion in an if statement.
The expression myErrorMsg.msgText.equals contains two member operators (that
is, two periods). This implies that two members (a data member and a method
member in this case) will be accessed.
Evaluate the expression this way: The data member msgText in the object myErrorMsg
is a String variable. As a result, it contains a method named equals() . This method
accepts a String parameter and returns a boolean result of true if the passed String
parameter contains the same text as is contained in this String . The boolean result is
evaluated by the if operator.
Multiple expressions can be grouped, and the result of such grouping will be eval-
uated. The logical operators AND (&&), OR(||), and NOT (!) group boolean expres-
sions in the same way their text equivalents do in COBOL. For example, this statement:
if (myErrorMsg.msgText.equals ("Any Text") ||
(myErrorMsg.msgText.equals ("Some Text")) {
... // The IF code block
}