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 flowanalysis

Project

ProjectBasedAnalysis

ProjectInformationKey

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

org.opalj

si

package si

Source: package.scala

Linear Supertypes

AnyRef, Any

Package Members

package flowanalysis

Type Members

trait Project extends AnyRef
trait ProjectBasedAnalysis extends AnyRef
Common super trait of all analyses that use the fixpoint computations framework.
Common super trait of all analyses that use the fixpoint computations framework. In general, an analysis computes a org.opalj.fpcf.Property by processing some entities, e.g.: ´classes´, ´methods´ or ´fields´.
trait ProjectInformationKey[-P <: Project, T <: AnyRef, I <: AnyRef] extends AnyRef
ProjectInformationKey objects are used to get/associate some (immutable) information with a project that should be computed on demand.
ProjectInformationKey objects are used to get/associate some (immutable) information with a project that should be computed on demand. For example, imagine that you write an analysis that requires – as a foundation – the project's call graph. In this case, to get the call graph it is sufficient to pass the respective key to the Project object. If the call graph was already computed that one will be returned, otherwise the computation will be performed and the result will be cached for future usage before it is returned.
Using Project Information
If access to some project information is required, it is sufficient to use the (singleton) instance of the respective ProjectInformationKey to get the respective project information.
For example, let's assume that an index of all fields and methods is needed. In this case the code to get the index would be:
```
import ...{ProjectIndex,ProjectIndexKey}
val project : Project = ???
val projectIndex = project.get(ProjectIndexKey)
// do something with the index
```
Providing Project Information/Implementing ProjectInformationKey
Making project wide information available on demand is done as follows.
1. Implement the base analysis that computes the information given some project.
2. Implement your ProjectInformationKey class that inherits from this trait and which calls the base analysis. It is recommended that the factory method (compute) is side-effect free.
Threading
Project takes care of threading related issues. The methods requirements and compute will never be called concurrently w.r.t. the same project object. However, concurrent calls may happen w.r.t. two different project objects.
Caching
Project takes care of the caching of the result of the computation of the information.
T
The type of the information object that is derived.
I
The type of information used at initialization time.
type ProjectInformationKeys = Seq[ProjectInformationKey[_ <: Project, _ <: AnyRef, _ <: AnyRef]]

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

si

package si

Package Members

Type Members

Using Project Information

Providing Project Information/Implementing `ProjectInformationKey`

Threading

Caching

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

si

package si

Package Members

Type Members

Using Project Information

Providing Project Information/Implementing ProjectInformationKey

Threading

Caching

Inherited from AnyRef

Inherited from Any

Ungrouped

No `null` Values

si

Providing Project Information/Implementing `ProjectInformationKey`