NestedTryDepth

Since Checkstyle 3.2

Description

Restricts nested try-catch-finally blocks to a specified depth.

Properties

name description type default value since
max Specify maximum allowed nesting depth. int 1 3.2

Examples

To configure the check: 

<module name="Checker">
  <module name="TreeWalker">
    <module name="NestedTryDepth"/>
  </module>
</module>

case 1: Example of code with violation: 

try {
    try {
        try { // violation, current depth is 2, default max allowed depth is 1
        } catch (Exception e) {
        }
    } catch (Exception e) {
    }
} catch (Exception e) {
}

case 1: Example of compliant code: 

try {
    try { // OK, current depth is 1, default max allowed depth is also 1
    } catch (Exception e) {
    }
} catch (Exception e) {
}

case 2: Example of code for handling unique and general exceptions

try {
    try { // OK, current depth is 1, default max allowed depth is also 1
            // any more nesting could cause code violation!
            throw ArithmeticException();
    } catch (ArithmeticException e) { // catches arithmetic exceptions
    } catch (NumberFormatException e) { // catches number-format exceptions
    } catch (Exception e) { // catches general exceptions other than stated above
    }
} catch (
  ArithmeticException
  | NumberFormatException
  | ArrayIndexOutOfBoundsException e) { // catches any of the 3 exception
} catch (Exception e) { // catches general exception
} finally { // do something when try-catch block finished execution
}

To configure the check to allow nesting depth 3: 

<module name="Checker">
  <module name="TreeWalker">
    <module name="NestedTryDepth">
      <property name="max" value="3"/>
    </module>
  </module>
</module>

Example of code with violation: 

try {
    try {
        try {
            try {
                try { // violation, current depth is 4, max allowed depth is 3
                } catch (Exception e) {
                }
            } catch (Exception e) {
            }
        } catch (Exception e) {
        }
    } catch (Exception e) {
    }
} catch (Exception e) {
}

Example of compliant code: 

try {
    try {
        try {
            try { // OK, current depth is 3, max allowed depth is also 3
            } catch (Exception e) {
            }
        } catch (Exception e) {
        }
    } catch (Exception e) {
    }
} catch (Exception e) {
}

Example of Usage

Violation Messages

All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.

Package

com.puppycrawl.tools.checkstyle.checks.coding

Parent Module

TreeWalker