Index_O

O

Object class, clone method of, 158

Object equivalence. See Equality (==) operator; equals method

Object graph, cutting by using transient keyword, 156

Object model for Library app, 64

Object pooling, 338

Object recycling, 338

Object reuse, 338

objectid-class attribute of metadata class tag, 31

ObjectOutputStream defaultWriteObject method, 153

Ockham's razor, 34

OIDString field, 242, 244

One-cache-per-PM architecture, 137–140

One-pm-per-request design (Web app), 334–335, 339–354

One-pm-per-request design example, 340–354

One-pm-per-session design (Web app), 334, 354–355

One-pm-per-update design (Web app), 335, 355–357

One-to-many relationship, select on join using, 68

One-to-one relationship, select on join using, 67–68

onMessage method, 225

open command, 297

Operators (JDOQL), 52–54

Optimistic concurrency check, 330

Optimistic concurrency value, 106

Optimistic lock failure, handling, 262–263

Optimistic property (transaction), 112–113, 124–127, 262

Optimistic transaction failure, view after, 310

Optimistic transactions, 105–106, 262–263, 315

vs. datastore transactions, 112–113

and flushing the cache, 64

for long-running transactions, 308

makeTransactional in, 85

performance boost for, 140

state transitions unique to, 127–129

for user think time, 112

Optimizations, for before-image, 119–120

OR operator (||), 53–54, 60

Oracle SELECT-FOR-UPDATE statement, 107

Ordering operator, 53

Ordering string (query results), 61

Ordering string property (query), 60

Outdated update, explained, 107

Overriding methods, 252