Packages

Definition Classes: root

Definition Classes: root

OPAL is a Scala-based framework for the static analysis, manipulation and creation of Java bytecode.

OPAL is a Scala-based framework for the static analysis, manipulation and creation of Java bytecode. OPAL is designed with performance, scalability and adaptability in mind.

Its main components are:

a library (Common) which provides generally useful data-structures and algorithms for static analyses.
a framework for implementing lattice based static analyses (Static Analysis Infrastructure)
a framework for parsing Java bytecode (Bytecode Infrastructure - org.opalj.bi) that can be used to create arbitrary representations.
a library to create a one-to-one in-memory representation of Java bytecode (Bytecode Disassembler - org.opalj.da).
a library to convert this representation to Java class files (Bytecode Creator - org.opalj.bc).
a library to create a representation of Java bytecode that facilitates writing simple static analyses (Bytecode Representation - org.opalj.br).
a library to create a stackless, three-address code representation of Java bytecode that facilitates writing complex static analyses (Three Address Code - org.opalj.tac).
a scalable, easily customizable framework for the abstract interpretation of Java bytecode (Abstract Interpretation Framework - org.opalj.ai).
a library to extract dependencies between code elements (Dependencies Extraction - org.opalj.de) and to facilitate checking architecture definitions (Architecture Validation - org.opalj.av).
a library for the lightweight manipulation and creation of Java bytecode (Bytecode Assembler - org.opalj.ba).
a library for parsing Android packages (APK - org.opalj.apk).
libraries for writing static analyses using the interprocedural finite distributive subset (IFDS - org.opalj.ifds) and interprocedural distributive environment (IDE - org.opal.ide) algorithms.

General Design Decisions

Thread Safety

Unless explicitly noted, OPAL is thread safe. I.e., the classes defined by OPAL can be considered to be thread safe unless otherwise stated. (For example, it is possible to read and process class files concurrently without explicit synchronization on the client side.)

No `null` Values

Unless explicitly noted, OPAL does not null values I.e., fields that are accessible will never contain null values and methods will never return null. If a method accepts null as a value for a parameter or returns a null value it is always explicitly documented. In general, the behavior of methods that are passed null values is undefined unless explicitly documented.

No Typecasts for Collections

For efficiency reasons, OPAL sometimes uses mutable data-structures internally. After construction time, these data-structures are generally represented using their generic interfaces (e.g., scala.collection.{Set,Map}). However, a downcast (e.g., to add/remove elements) is always forbidden as it would effectively prevent thread-safety.

Assertions

OPAL makes heavy use of Scala's Assertion Facility to facilitate writing correct code. Hence, for production builds (after thorough testing(!)) it is highly recommend to build OPAL again using -Xdisable-assertions.

Definition Classes: org

package ai

Implementation of an abstract interpretation (ai) framework.

Please note that the abstract interpreter just refers to the classes and traits defined in this package (ai). The classes and traits defined in the sub-packages (in particular in domain) are not considered to be part of the core of the abstract interpreter.

Definition Classes: opalj
Note: This framework assumes that the analyzed bytecode is valid; i.e., the JVM's bytecode verifier would be able to verify the code. Furthermore, load-time errors (e.g., LinkageErrors) are – by default – completely ignored to facilitate the analysis of parts of a project. In general, if the presented bytecode is not valid, the result is undefined (i.e., OPAL may report meaningless results, crash or run indefinitely).
See also: org.opalj.ai.AI - Implements the abstract interpreter that processes a methods code and uses an analysis-specific domain to perform the abstract computations.
org.opalj.ai.Domain - The core interface between the abstract interpretation framework and the abstract domain that is responsible for performing the abstract computations.

package apk

Definition Classes: opalj

package av

Definition Classes: opalj

package ba

Implementation of an eDSL for creating Java bytecode.

Implementation of an eDSL for creating Java bytecode. The eDSL is designed to facilitate the creation of correct class files; i.e., whenever possible it tries to fill wholes. For example, when an interface is specified the library automatically ensures that the super class type is (initially) set to java.lang.Object as required by the JVM specification.

This package in particular provides functionality to convert org.opalj.br classes to org.opalj.da classes.

Definition Classes: opalj

package bc

Definition Classes: opalj

package bi

Implementation of a library for parsing Java bytecode and creating arbitrary representations.

OPAL's primary representation of Java byte code is the org.opalj.br representation which is defined in the respective package. A second representation that represents bytecode one-by-one is found in the org.opalj.da package.

This Package

Common constants and type definitions used across OPAL.

Definition Classes: opalj

package br

In this representation of Java bytecode references to a Java class file's constant pool and to attributes are replaced by direct references to the corresponding constant pool entries.

In this representation of Java bytecode references to a Java class file's constant pool and to attributes are replaced by direct references to the corresponding constant pool entries. This facilitates developing analyses and fosters comprehension.

Based on the fact that indirect references to constant pool entries are resolved and replaced by direct references this representation is called the resolved representation.

This representation of Java bytecode is considered as OPAL's standard representation for writing simple Scala based analyses. This representation is engineered such that it facilitates writing analyses that use pattern matching.

Definition Classes: opalj

package bytecode

Defines functionality commonly useful when processing Java bytecode.

Definition Classes: opalj

package ce

Definition Classes: opalj

package cli

Definition Classes: opalj

package collection

OPAL's collection library is primarily designed with high performance in mind.

Design Goals

OPAL's collection library is primarily designed with high performance in mind. I.e., all methods provided by the collection library are reasonably optimized. However, providing a very large number of methods is a non-goal. Overall, OPAL's collection library provides:

collection classes that are manually specialized for primitive data-types.
collection classes that are optimized for particularly small collections of values.
collection classes that target special use cases such as using a collection as a workset/worklist.
collection classes that offer special methods that minimize the number of steps when compared to general purpose methods.

Integration With Scala's Collection Library

Hence, OPAL's collection library complements Scala's default collection library and is not intended to replace it. Integration with Scala's collection library is primarily provided by means of iterators (OPAL's Iterators inherit from Scala's Iterators). Furthermore the companion object of each of OPAL's collection classes generally provides factory methods that facilitate the conversion from Scala collection classes to OPAL collection classes.

Status

The collection library is growing. Nevertheless, the existing classes are production ready.

Definition Classes: opalj

package concurrent

Common constants, factory methods and objects used throughout OPAL when performing concurrent computations.

Definition Classes: opalj

package constraints

Defines helper values and methods related to modeling constraints.

Definition Classes: opalj

package control

Defines common control abstractions.

Definition Classes: opalj

package da

Defines convenience methods related to representing certain class file elements.

Definition Classes: opalj

package de

Functionality to extract dependencies between class files.

Definition Classes: opalj

package fpcf

The fixpoint computations framework (fpcf) is a general framework to perform fixpoint computations of properties ordered by a lattice.

The fixpoint computations framework (fpcf) is a general framework to perform fixpoint computations of properties ordered by a lattice. The framework in particular supports the development of static analyses.

In this case, the fixpoint computations/static analyses are generally operating on the code and need to be executed until the computations have reached their (implicit) fixpoint. The fixpoint framework explicitly supports resolving cyclic dependencies/computations. A prime use case of the fixpoint framework are all those analyses that may interact with the results of other analyses.

For example, an analysis that analyzes all field write accesses to determine if we can refine a field's type (for the purpose of the analysis) can (reuse) the information about the return types of methods, which however may depend on the refined field types.

The framework is generic enough to facilitate the implementation of anytime algorithms.

Definition Classes: opalj
Note: This framework assumes that all data-structures (e.g., dependee lists and properties) that are passed to the framework are effectively immutable! (Effectively immutable means that a data structure is never updated after it was passed to the framework.)
,
The dependency relation is as follows: “A depends on B” === “A is the depender, B is the dependee”. === “B is depended on by A”
,
The very core of the framework is described in: Lattice Based Modularization of Static Analyses

package graphs

This package defines graph algorithms as well as factory methods to describe and compute graphs and trees.

This package supports the following types of graphs:

graphs based on explicitly connected nodes (org.opalj.graphs.Node),
graphs where the relationship between the nodes are encoded externally (org.opalj.graphs.Graph).

Definition Classes: opalj

package ide

Definition Classes: opalj

package ifds

Definition Classes: opalj

package io

Various io-related helper methods and classes.

Definition Classes: opalj
Note: The implementations of the methods rely on Java NIO(2).

package issues

Defines implicit conversions to wrap some types of analyses such that they generate results of type org.opalj.br.analyses.ReportableAnalysisResult.

Definition Classes: opalj

package log

Definition Classes: opalj

package si

Definition Classes: opalj

package tac

Common definitions related to the definition and processing of three address code.

Definition Classes: opalj

package util

Utility methods.

Definition Classes: opalj

package value

Provides a general query interface for querying a value's properties.

Definition Classes: opalj

Answer

BinaryArithmeticOperators

UnaryArithmeticOperators

Unknown

Yes

org.opalj

Answer

Companion object Answer

sealed trait Answer extends AnyRef

Models a three state answer (Yes, No, Unknown).

Source: Answer.scala

Linear Supertypes

AnyRef, Any

Known Subclasses

No, Unknown, Yes

Ordering

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By Inheritance

Inherited

Answer
AnyRef
Any

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Visibility

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Protected

Abstract Value Members

abstract def &&(other: Answer): Answer
The logical conjunction of this answer and the given answer.
The logical conjunction of this answer and the given answer. In this case Unknown is considered to either represent the answer Yes or No; hence, this && other is treated as this && (Yes || No).
abstract def ifUnknown(f: => Answer): Answer
If this answer is unknown the given function is evaluated and that result is returned, otherwise this answer is returned.
abstract def isNo: Boolean
Returns true if and only if this answer is No.
Returns true if and only if this answer is No.
Effectively the same as a comparison with No.
abstract def isNotNo: Boolean
Returns true if this answer is Yes or Unknown, false otherwise.
abstract def isNotYes: Boolean
Returns true if this answer is No or Unknown, false otherwise.
abstract def isUnknown: Boolean
Returns true if and only if this answer is Unknown.
Returns true if and only if this answer is Unknown.
Effectively the same as a comparison with Unknown.
abstract def isYes: Boolean
Returns true if and only if this answer is Yes.
Returns true if and only if this answer is Yes.
Effectively the same as a comparison with Yes.
abstract def isYesOrNo: Boolean
Returns true if this answer is either Yes or No; false if this answer is Unknown.
abstract def join(other: Answer): Answer
Joins this answer and the given answer.
Joins this answer and the given answer. In this case Unknown will represent the case that we have both answers; that is we have a set based view w.r.t. Answers. Hence, this join Unknown is considered as this join {Yes, No} where the set {Yes, No} is represented by Unknown.
If the other Answer is identical to this answer this is returned, otherwise Unknown is returned.
abstract def negate: Answer
The negation of this Answer.
The negation of this Answer. If the answer is Unknown the negation is still Unknown.
abstract def ||(other: Answer): Answer
The logical disjunction of this answer and the given answer.
The logical disjunction of this answer and the given answer. In this case Unknown is considered to either represent the answer Yes or No; hence, this || other is treated as this || (Yes || No).

Concrete Value Members

final def !=(arg0: Any): Boolean
Definition Classes
AnyRef → Any
final def ##: Int
Definition Classes
AnyRef → Any
final def &&(other: Boolean): Answer
final def ==(arg0: Any): Boolean
Definition Classes
AnyRef → Any
final def asInstanceOf[T0]: T0
Definition Classes
Any
def clone(): AnyRef
Attributes
protected[lang]
Definition Classes
AnyRef
Annotations
@throws(classOf[java.lang.CloneNotSupportedException]) @native() @IntrinsicCandidate()
final def eq(arg0: AnyRef): Boolean
Definition Classes
AnyRef
def equals(arg0: AnyRef): Boolean
Definition Classes
AnyRef → Any
final def getClass(): Class[_ <: AnyRef]
Definition Classes
AnyRef → Any
Annotations
@native() @IntrinsicCandidate()
def hashCode(): Int
Definition Classes
AnyRef → Any
Annotations
@native() @IntrinsicCandidate()
final def isInstanceOf[T0]: Boolean
Definition Classes
Any
final def isNoOrUnknown: Boolean
Returns true if this answer is No or Unknown, false otherwise.
final def isYesOrUnknown: Boolean
Returns true if this answer is Yes or Unknown, false otherwise.
final def ne(arg0: AnyRef): Boolean
Definition Classes
AnyRef
final def notify(): Unit
Definition Classes
AnyRef
Annotations
@native() @IntrinsicCandidate()
final def notifyAll(): Unit
Definition Classes
AnyRef
Annotations
@native() @IntrinsicCandidate()
final def synchronized[T0](arg0: => T0): T0
Definition Classes
AnyRef
def toString(): String
Definition Classes
AnyRef → Any
final def unary_!: Answer
See also
Answer#negate
final def wait(arg0: Long, arg1: Int): Unit
Definition Classes
AnyRef
Annotations
@throws(classOf[java.lang.InterruptedException])
final def wait(arg0: Long): Unit
Definition Classes
AnyRef
Annotations
@throws(classOf[java.lang.InterruptedException])
final def wait(): Unit
Definition Classes
AnyRef
Annotations
@throws(classOf[java.lang.InterruptedException])
final def ||(other: Boolean): Answer

Deprecated Value Members

def finalize(): Unit
Attributes
protected[lang]
Definition Classes
AnyRef
Annotations
@throws(classOf[java.lang.Throwable]) @Deprecated @Deprecated
Deprecated

Packages

General Design Decisions

Thread Safety

No `null` Values

No Typecasts for Collections

Assertions

This Package

Design Goals

Integration With Scala's Collection Library

Status

Answer

Companion object Answer

sealed trait Answer extends AnyRef

Abstract Value Members

Concrete Value Members

Deprecated Value Members

Inherited from AnyRef

Inherited from Any

Ungrouped

Packages

General Design Decisions

Thread Safety

No null Values

No Typecasts for Collections

Assertions

This Package

Design Goals

Integration With Scala's Collection Library

Status

Answer

Companion object Answer

sealed trait Answer extends AnyRef

Abstract Value Members

Concrete Value Members

Deprecated Value Members

Inherited from AnyRef

Inherited from Any

Ungrouped

No `null` Values

Answer