Liskov substitution principle Violation

lsp_violation.php

<?php

// conditions are just semantic value objects containing constraint data
// handlers now how to interact with a condition it supports and operates on the given $querybuilder

// The LSP Violation happens in the generateCondition() method of the handler where we want to pull additional values from the condition object.

$condition = new SearchTermCondition("foobar");
$handler = new SearchTermConditionHandler();

if ($handler->supportsCondition($condition)) {
   $handler->generateCondition($condition, $queryBuilder);
}



interface ConditionInterface
{
    public function getName();
}

interface ConditionHandlerInterface
{
    public function supportsCondition(ConditionInterface $condition);

    public function generateCondition(
        ConditionInterface $condition,
        QueryBuilder $qb,
    );
}

class SearchTermCondition implements ConditionInterface
{
    public function __construct($term)
    {
        $this->term = $term;
    }

    public function getName()
    public function getTerm(); // additional method not defined in ConditionInterface
}

class SearchTermConditionHandler implements ConditionHandlerInterface
{
    public function supportsCondition(ConditionInterface $condition)
    {
        return ($condition instanceof SearchTermCondition);
    }

    public function generateCondition(ConditionInterface $condition, QueryBuilder $qb) 
    {
        $term = $condition->getTerm(); // Violation of LSP, getTerm() is not defined in ConditionInterface

        $qb->andWhere('term = ?', $term)
    }
}