AspectJ Weaver 1.9.20.1 · org.aspectj.weaver.WeakClassLoaderReference

Wraps a reference to a classloader inside a WeakReference. This should be used where we do not want the existence of a classloader reference to prevent garbage collection of that classloader (and possibly an associated weaver instance in the case of load time weaving).

In more detail:
When load time weaving, the class Aj maintains a WeakHashMap from the classloader instance to a weaver instance. The aim is that the weaver is around as long as the classloader is and should the classloader be dereferenced then the weaver can also be garbage collected. The problem is that if there are many references to the classloader from within the weaver, these are considered hard references and cause the classloader to be long lived - even if the user of the classloader has dereferenced it in their code. The solution is that the weaver should use instances of WeakClassLoaderReference objects - so that when the users hard reference to the classloader goes, nothing in the weaver will cause it to hang around. There is a big assertion here that the WeakClassLoaderReference instances will not 'lose' their ClassLoader references until the top level ClassLoader reference is null'd. This means there is no need to check for the null case on get() in this WeakReference logic below, because we shouldn't be using this weaver if its associated ClassLoader has been collected. See https://bugs.eclipse.org/bugs/show_bug.cgi?id=210470

Modifier and Type	Field and Description
protected final int	hashcode
private final WeakReference<ClassLoader>	loaderRef

Access	Constructor and Description
public	WeakClassLoaderReference(ClassLoader loader)

Modifier and Type	Method and Description
public boolean	equals(Object the reference object with which to compare. obj) Overrides java.lang.Object.equals. Indicates whether some other object is "equal to" this one.
public ClassLoader	getClassLoader()
public int	hashCode() Overrides java.lang.Object.hashCode. Returns a hash code value for the object.

hashcode	back to summary
protected final int hashcode

loaderRef	back to summary
private final WeakReference<ClassLoader> loaderRef

WeakClassLoaderReference	back to summary
public WeakClassLoaderReference(ClassLoader loader)

Method Detail

equals back to summary

equals	back to summary
public boolean equals(Object obj) Overrides java.lang.Object.equals. Doc from java.lang.Object.equals. Indicates whether some other object is "equal to" this one. The `equals` method implements an equivalence relation on non-null object references: It is reflexive: for any non-null reference value `x`, `x.equals(x)` should return `true`. It is symmetric: for any non-null reference values `x` and `y`, `x.equals(y)` should return `true` if and only if `y.equals(x)` returns `true`. It is transitive: for any non-null reference values `x`, `y`, and `z`, if `x.equals(y)` returns `true` and `y.equals(z)` returns `true`, then `x.equals(z)` should return `true`. It is consistent: for any non-null reference values `x` and `y`, multiple invocations of `x.equals(y)` consistently return `true` or consistently return `false`, provided no information used in `equals` comparisons on the objects is modified. For any non-null reference value `x`, `x.equals(null)` should return `false`. An equivalence relation partitions the elements it operates on into equivalence classes; all the members of an equivalence class are equal to each other. Members of an equivalence class are substitutable for each other, at least for some purposes. Parameters obj:Object the reference object with which to compare. Returns:boolean `true` if this object is the same as the obj argument; `false` otherwise.

public boolean equals(Object obj)

Overrides java.lang.Object.equals.

Doc from java.lang.Object.equals.

Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

It is reflexive: for any non-null reference value x, x.equals(x) should return true.
It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
For any non-null reference value x, x.equals(null) should return false.

An equivalence relation partitions the elements it operates on into equivalence classes; all the members of an equivalence class are equal to each other. Members of an equivalence class are substitutable for each other, at least for some purposes.

Parameters

obj:Object: the reference object with which to compare.

Returns:boolean

true if this object is the same as the obj argument; false otherwise.

getClassLoader	back to summary
public ClassLoader getClassLoader()

hashCode back to summary

hashCode	back to summary
public int hashCode() Overrides java.lang.Object.hashCode. Doc from java.lang.Object.hashCode. Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by `java.util.HashMap`. The general contract of `hashCode` is: Whenever it is invoked on the same object more than once during an execution of a Java application, the `hashCode` method must consistently return the same integer, provided no information used in `equals` comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application. If two objects are equal according to the `equals` method, then calling the `hashCode` method on each of the two objects must produce the same integer result. It is not required that if two objects are unequal according to the `equals` method, then calling the `hashCode` method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables. Returns:int a hash code value for this object.

public int hashCode()

Overrides java.lang.Object.hashCode.

Doc from java.lang.Object.hashCode.

Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by java.util.HashMap.

The general contract of hashCode is:

Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
If two objects are equal according to the equals method, then calling the hashCode method on each of the two objects must produce the same integer result.
It is not required that if two objects are unequal according to the equals method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.

Returns:int: a hash code value for this object.

public Class WeakClassLoaderReference

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail