Apache Derby Database Engine and Embedded JDBC Driver 10.17.1.0 · org.apache.derby.impl.services.reflect.JarLoader

Modifier and Type	Field and Description
private StorageFile	installedJar Handle to the installed jar file.
private boolean	isStream True if the jar can only be accessed using a stream, because the jar is itself in a database jar.
private JarFile	jar When the jar file can be manipulated as a java.util.JarFile this holds the reference to the open jar.
private final String[]	name Hides java.lang.ClassLoader.name. Two part name for the jar file.
private UpdateLoader	updateLoader
private HeaderPrintWriter	vs

Access	Constructor and Description
pack-priv	JarLoader(UpdateLoader updateLoader, String[] name, HeaderPrintWriter vs)

Method Summary

Modifier and Type	Method and Description
pack-priv Class<T>	checkLoaded(String className, boolean resolve)
pack-priv final String	getJarName() Return the SQL name for the installed jar.
private InputStream	getRawStream(String name) Get a stream for a resource directly from a JarFile.
private InputStream	getRawStream(InputStream in, String name) Get a stream from a zip file that is itself a stream.
public InputStream	getResourceAsStream(String The resource name name) Overrides java.lang.ClassLoader.getResourceAsStream. Returns an input stream for reading the specified resource.
private Certificate[]	getSigners(String className, JarEntry je) Validate the security certificates (signers) for the class data.
pack-priv InputStream	getStream(String name) Get an InputStream for the given resource.
private SecurityException	handleException(Exception e, String className) Provide a SecurityException with information about the class name and the jar file.
pack-priv void	initialize() Initialize the class loader so it knows if it is loading from a ZipFile or an InputStream
private boolean	isDerbyDriver(String className) Return true if the class is a Derby driver class which must be accessible to java.sql.DriverManager.
protected Class<T>	loadClass(String The binary name of the class className, boolean If `true` then resolve the class resolve) Overrides java.lang.ClassLoader.loadClass. Handle all requests to the top-level loader.
pack-priv Class<T>	loadClassData(String className, String jvmClassName, boolean resolve)
private Class<T>	loadClassData(InputStream in, String className, String jvmClassName, boolean resolve) Load the class data when the installed jar is accessible only as an input stream (the jar is itself in a database jar).
private Class<T>	loadClassData(JarEntry e, InputStream in, String className, boolean resolve) Load and optionally resolve the class given its JarEntry and an InputStream to the class fiel format.
private Class<T>	loadClassDataFromJar(String className, String jvmClassName, boolean resolve) Load the class data when the installed jar is accessible as a java.util.jarFile.
pack-priv byte[]	readData(JarEntry ze, InputStream in, String className) Read the raw data for the class file format into a byte array that can be used for loading the class.
pack-priv void	setInvalid() Set this loader to be invaid so that it will not resolve any classes or resources.
public String	toString() Overrides java.lang.Object.toString. Return the jar name if toString() is called on this class loader.

Inherited from java.security.SecureClassLoader:: defineClass defineClass getPermissions

installedJar	back to summary
private StorageFile installedJar Handle to the installed jar file.

isStream	back to summary
private boolean isStream True if the jar can only be accessed using a stream, because the jar is itself in a database jar. When fals the jar is accessed using the jar field.

jar	back to summary
private JarFile jar When the jar file can be manipulated as a java.util.JarFile this holds the reference to the open jar. When the jar can only be manipulated as an InputStream (because the jar is itself in a database jar) then this will be null.

name	back to summary
private final String[] name Hides java.lang.ClassLoader.name. Two part name for the jar file.

updateLoader	back to summary
private UpdateLoader updateLoader

vs	back to summary
private HeaderPrintWriter vs

JarLoader	back to summary
pack-priv JarLoader(UpdateLoader updateLoader, String[] name, HeaderPrintWriter vs)

Method Detail

checkLoaded	back to summary
pack-priv Class<T> checkLoaded(String className, boolean resolve)

getJarName	back to summary
pack-priv final String getJarName() Return the SQL name for the installed jar. Used for error and informational messages.

getRawStream	back to summary
private InputStream getRawStream(String name) Get a stream for a resource directly from a JarFile. In this case we can safely return the stream directly. It's a new stream set up by the zip code to read just the contents of this entry.

getRawStream	back to summary
private InputStream getRawStream(InputStream in, String name) Get a stream from a zip file that is itself a stream. We copy to the contents to a byte array and return a stream around that to the caller. Though a copy is involved it has the benefit of: Isolating the application from the JarInputStream, thus denying any possibility of the application reading more of the jar that it should be allowed to. E.g. the contents class files are not exposed through getResource. Avoids any possibility of the application holding onto the open stream beyond shutdown of the database, thus leading to leaked file descriptors or inability to remove the jar.

getRawStream

back to summary

private InputStream getRawStream(InputStream in, String name)

Get a stream from a zip file that is itself a stream. We copy to the contents to a byte array and return a stream around that to the caller. Though a copy is involved it has the benefit of:

Isolating the application from the JarInputStream, thus denying any possibility of the application reading more of the jar that it should be allowed to. E.g. the contents class files are not exposed through getResource.
Avoids any possibility of the application holding onto the open stream beyond shutdown of the database, thus leading to leaked file descriptors or inability to remove the jar.

getResourceAsStream back to summary

getResourceAsStream	back to summary
public InputStream getResourceAsStream(String name) Overrides java.lang.ClassLoader.getResourceAsStream. Doc from java.lang.ClassLoader.getResourceAsStream. Returns an input stream for reading the specified resource. The search order is described in the documentation for `getResource(String)`. Resources in named modules are subject to the encapsulation rules specified by `Module.getResourceAsStream`. Additionally, and except for the special case where the resource has a name ending with "`.class`", this method will only find resources in packages of named modules when the package is `opened` unconditionally. Parameters name:String The resource name Returns:InputStream An input stream for reading the resource; `null` if the resource could not be found, the resource is in a package that is not opened unconditionally, or access to the resource is denied by the security manager.

public InputStream getResourceAsStream(String name)

Overrides java.lang.ClassLoader.getResourceAsStream.

Doc from java.lang.ClassLoader.getResourceAsStream.

Returns an input stream for reading the specified resource.

The search order is described in the documentation for getResource(String).

Resources in named modules are subject to the encapsulation rules specified by Module.getResourceAsStream. Additionally, and except for the special case where the resource has a name ending with ".class", this method will only find resources in packages of named modules when the package is opened unconditionally.

Parameters

name:String: The resource name

Returns:InputStream

An input stream for reading the resource; null if the resource could not be found, the resource is in a package that is not opened unconditionally, or access to the resource is denied by the security manager.

getSigners	back to summary
private Certificate[] getSigners(String className, JarEntry je) throws IOException Validate the security certificates (signers) for the class data.

getStream	back to summary
pack-priv InputStream getStream(String name) Get an InputStream for the given resource.

handleException	back to summary
private SecurityException handleException(Exception e, String className) Provide a SecurityException with information about the class name and the jar file.

initialize	back to summary
pack-priv void initialize() Initialize the class loader so it knows if it is loading from a ZipFile or an InputStream

isDerbyDriver	back to summary
private boolean isDerbyDriver(String className) Return true if the class is a Derby driver class which must be accessible to java.sql.DriverManager.

loadClass back to summary

loadClass	back to summary
protected Class<T> loadClass(String className, boolean resolve) throws ClassNotFoundException Overrides java.lang.ClassLoader.loadClass. Handle all requests to the top-level loader. Parameters className:String Doc from java.lang.ClassLoader.loadClass. The binary name of the class resolve:boolean Doc from java.lang.ClassLoader.loadClass. If `true` then resolve the class Returns:Class<T> Doc from java.lang.ClassLoader.loadClass. The resulting `Class` object Exceptions ClassNotFoundException: Class can not be found

protected Class<T> loadClass(String className, boolean resolve) throws ClassNotFoundException

Overrides java.lang.ClassLoader.loadClass.

Handle all requests to the top-level loader.

Parameters

className:String

Doc from java.lang.ClassLoader.loadClass.

The binary name of the class

resolve:boolean

Doc from java.lang.ClassLoader.loadClass.

If true then resolve the class

Returns:Class<T>

Doc from java.lang.ClassLoader.loadClass.

The resulting Class object

Exceptions

ClassNotFoundException:: Class can not be found

loadClassData	back to summary
pack-priv Class<T> loadClassData(String className, String jvmClassName, boolean resolve)

loadClassData	back to summary
private Class<T> loadClassData(InputStream in, String className, String jvmClassName, boolean resolve) throws IOException Load the class data when the installed jar is accessible only as an input stream (the jar is itself in a database jar).

loadClassData	back to summary
private Class<T> loadClassData(JarEntry e, InputStream in, String className, boolean resolve) throws IOException Load and optionally resolve the class given its JarEntry and an InputStream to the class fiel format. This is common code for when the jar is accessed directly using JarFile or through InputStream.

loadClassDataFromJar	back to summary
private Class<T> loadClassDataFromJar(String className, String jvmClassName, boolean resolve) throws IOException Load the class data when the installed jar is accessible as a java.util.jarFile.

readData	back to summary
pack-priv byte[] readData(JarEntry ze, InputStream in, String className) throws IOException Read the raw data for the class file format into a byte array that can be used for loading the class. If this is a signed class and it has been compromised then an IOException will be thrown.

setInvalid	back to summary
pack-priv void setInvalid() Set this loader to be invaid so that it will not resolve any classes or resources.

toString	back to summary
public String toString() Overrides java.lang.Object.toString. Return the jar name if toString() is called on this class loader. Returns:String Doc from java.lang.Object.toString. a string representation of the object

toString

back to summary

public String toString()

Overrides java.lang.Object.toString.

Return the jar name if toString() is called on this class loader.

Returns:String

Doc from java.lang.Object.toString.

a string representation of the object

pack-priv final Class JarLoader

Field Summary

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Field Detail

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