AbstractClasspathResource (Apache Ant API)
Date: 2018-03-24

org.apache.tools.ant.types.resources

## Class AbstractClasspathResource

- java.lang.Object
- - org.apache.tools.ant.ProjectComponent
  - - org.apache.tools.ant.types.DataType
    - - org.apache.tools.ant.types.Resource
      - - org.apache.tools.ant.types.resources.AbstractClasspathResource

- All Implemented Interfaces:
    java.lang.Cloneable, java.lang.Comparable<Resource>, java.lang.Iterable<Resource>, ResourceCollection
  Direct Known Subclasses:
    JavaConstantResource, JavaResource

      public abstract class AbstractClasspathResource
      extends Resource

  A Resource representation of anything that is accessed via a Java classloader. The core methods to set/resolve the classpath are provided.
  Since:
    Ant 1.8.0

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static class` | `AbstractClasspathResource.ClassLoaderWithFlag`

  - ### Field Summary

    - ### Fields inherited from class org.apache.tools.ant.types.Resource

      `MAGIC, UNKNOWN_DATETIME, UNKNOWN_SIZE`

    - ### Fields inherited from class org.apache.tools.ant.types.DataType

      `checked, ref`

    - ### Fields inherited from class org.apache.tools.ant.ProjectComponent

      `description, location, project`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `AbstractClasspathResource()`

  - ### Method Summary

    All Methods Instance Methods Abstract Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `Path` | `createClasspath()` Add a classpath to use when looking up a resource.
    `protected void` | `dieOnCircularReference(java.util.Stack<java.lang.Object> stk, Project p)` Check to see whether any DataType we hold references to is included in the Stack (which holds all DataType instances that directly or indirectly reference this instance, including this instance itself).
    `protected AbstractClasspathResource.ClassLoaderWithFlag` | `getClassLoader()` combines the various ways that could specify a ClassLoader and potentially creates one that needs to be cleaned up when it is no longer needed so that classes can get garbage collected.
    `Path` | `getClasspath()` get the classpath used by this `LoadProperties`.
    `java.io.InputStream` | `getInputStream()` Return an InputStream for reading the contents of this Resource.
    `Reference` | `getLoader()` Get the loader.
    `boolean` | `isExists()` Learn whether this resource exists.
    `protected abstract java.io.InputStream` | `openInputStream(java.lang.ClassLoader cl)` open the input stream from a specific classloader
    `void` | `setClasspath(Path classpath)` Set the classpath to use when looking up a resource.
    `void` | `setClasspathRef(Reference r)` Set the classpath to use when looking up a resource, given as reference to a <path> defined elsewhere
    `void` | `setLoaderRef(Reference r)` Use the reference to locate the loader.
    `void` | `setParentFirst(boolean b)` Whether to consult the parent classloader first.
    `void` | `setRefid(Reference r)` Overrides the super version.

    - ### Methods inherited from class org.apache.tools.ant.types.Resource

      `as, asOptional, clone, compareTo, equals, getCheckedRef, getLastModified, getMagicNumber, getName, getOutputStream, getSize, hashCode, isDirectory, isFilesystemOnly, iterator, setDirectory, setExists, setLastModified, setName, setSize, size, toLongString, toString`

    - ### Methods inherited from class org.apache.tools.ant.types.DataType

      `checkAttributesAllowed, checkChildrenAllowed, circularReference, dieOnCircularReference, dieOnCircularReference, getCheckedRef, getCheckedRef, getCheckedRef, getDataTypeName, getRefid, invokeCircularReferenceCheck, isChecked, isReference, noChildrenAllowed, pushAndInvokeCircularReferenceCheck, setChecked, tooManyAttributes`

    - ### Methods inherited from class org.apache.tools.ant.ProjectComponent

      `getDescription, getLocation, getProject, log, log, setDescription, setLocation, setProject`

    - ### Methods inherited from class java.lang.Object

      `finalize, getClass, notify, notifyAll, wait, wait, wait`

    - ### Methods inherited from interface org.apache.tools.ant.types.ResourceCollection

      `isEmpty, stream`

    - ### Methods inherited from interface java.lang.Iterable

      `forEach, spliterator`

- - ### Constructor Detail

    - #### AbstractClasspathResource

          public AbstractClasspathResource()

  - ### Method Detail

    - #### setClasspath

          public void setClasspath(Path classpath)

      Set the classpath to use when looking up a resource.
      Parameters:
        `classpath` - to add to any existing classpath

    - #### createClasspath

          public Path createClasspath()

      Add a classpath to use when looking up a resource.
      Returns:
        The classpath to be configured

    - #### setClasspathRef

          public void setClasspathRef(Reference r)

      Set the classpath to use when looking up a resource, given as reference to a <path> defined elsewhere
      Parameters:
        `r` - The reference value

    - #### getClasspath

          public Path getClasspath()

      get the classpath used by this `LoadProperties`.
      Returns:
        The classpath

    - #### getLoader

          public Reference getLoader()

      Get the loader.
      Returns:
        the loader.

    - #### setLoaderRef

          public void setLoaderRef(Reference r)

      Use the reference to locate the loader. If the loader is not found, taskdef will use the specified classpath and register it with the specified name.

      This allow multiple taskdef/typedef to use the same class loader, so they can be used together. It eliminate the need to put them in the CLASSPATH.

      Parameters:
        `r` - the reference to locate the loader.

    - #### setParentFirst

          public void setParentFirst(boolean b)

      Whether to consult the parent classloader first.

      Only relevant if a classpath has been specified.

      Parameters:
        `b` - boolean
      Since:
        Ant 1.8.0

    - #### setRefid

          public void setRefid(Reference r)

      Overrides the super version.
      Overrides:
        `setRefid` in class `Resource`
      Parameters:
        `r` - the Reference to set.

    - #### isExists

          public boolean isExists()

      Learn whether this resource exists. This implementation opens the input stream as the test.
      Overrides:
        `isExists` in class `Resource`
      Returns:
        true if this resource exists.

    - #### getInputStream

          public java.io.InputStream getInputStream()
                                             throws java.io.IOException

      Return an InputStream for reading the contents of this Resource.
      Overrides:
        `getInputStream` in class `Resource`
      Returns:
        an InputStream object.
      Throws:
        `java.io.IOException` - if an error occurs.

    - #### getClassLoader

          protected AbstractClasspathResource.ClassLoaderWithFlag getClassLoader()

      combines the various ways that could specify a ClassLoader and potentially creates one that needs to be cleaned up when it is no longer needed so that classes can get garbage collected.
      Returns:
        ClassLoaderWithFlag

    - #### openInputStream

          protected abstract java.io.InputStream openInputStream(java.lang.ClassLoader cl)
                                                          throws java.io.IOException

      open the input stream from a specific classloader
      Parameters:
        `cl` - the classloader to use. Will be null if the system classloader is used
      Returns:
        an open input stream for the resource
      Throws:
        `java.io.IOException` - if an error occurs.

    - #### dieOnCircularReference

          protected void dieOnCircularReference(java.util.Stack<java.lang.Object> stk,
                                                Project p)

      Description copied from class: `DataType`
      Check to see whether any DataType we hold references to is included in the Stack (which holds all DataType instances that directly or indirectly reference this instance, including this instance itself).

      If one is included, throw a BuildException created by `circularReference`.

      This implementation is appropriate only for a DataType that cannot hold other DataTypes as children.

      The general contract of this method is that it shouldn't do anything if `DataType.checked` is true and set it to true on exit.

      Overrides:
        `dieOnCircularReference` in class `DataType`
      Parameters:
        `stk` - the stack of references to check.
        `p` - the project to use to dereference the references.