@Override
    public final int hashCode() {
        if (hashCode == null) {
            hashCode = accept(HashCodeVisitor.DEFAULT, null);
        }
        return hashCode;
    }
{@code ExpressionBase} is the base class for immutable {@link Expression} implementations

@author tiwe

@param <T> expression type
querydsl-core/src/main/java/com/querydsl/core/types/ExpressionBase.java