print/attribute/AttributeSetUtilities.java

/* AttributeSetUtilities.java --
   Copyright (C) 2003, 2004, 2006  Free Software Foundation, Inc.

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package javax.print.attribute;

import java.io.Serializable;

/**
 * <code>AttributeSetUtilities</code> provides static methods for working
 * with <code>AttributeSet</code>s.
 * <p>
 * For every type of an attribute set available in the Java Print Service API
 * are methods provided to get an unmodifiable view of an attribute set.
 * This unmodifiable view provides a read-only version of the attribute
 * set which throws {@link javax.print.attribute.UnmodifiableSetException}s
 * if state changing methods are invoked.
 * </p>
 * <p>
 * Methods for getting a synchronized view of an attribute set are also
 * available. This view provides synchronized (thread safe) access to the
 * underlying wrapped attribute set.
 * </P>
 * <p>
 * Three static methods for the implementation of own AttributeSets
 * are provided, which verify that:
 * <ul>
 * <li>the given object is an attribute of the given interface.</li>
 * <li>the category of given attribute is equals to a given category.</li>
 * <li>the given object is a <code>Class</code> that implements the given
 * interface name.</li>
 * </ul>
 *
 */
public final class AttributeSetUtilities
{
  /**
   * This class isn't intended to be instantiated.
   */
  private AttributeSetUtilities()
  {
    // only static methods
  }

  private static class UnmodifiableAttributeSet
    implements AttributeSet, Serializable
  {
    private AttributeSet attrset;

    public UnmodifiableAttributeSet(AttributeSet attributeSet)
    {
      if (attributeSet == null)
        throw new NullPointerException("attributeSet may not be null");

      this.attrset = attributeSet;
    }

    public boolean add(Attribute attribute)
    {
      throw new UnmodifiableSetException();
    }

    public boolean addAll(AttributeSet attributes)
    {
      throw new UnmodifiableSetException();
    }

    public void clear()
    {
      throw new UnmodifiableSetException();
    }

    public boolean containsKey(Class category)
    {
      return attrset.containsKey(category);
    }

    public boolean containsValue(Attribute attribute)
    {
      return attrset.containsValue(attribute);
    }

    public boolean equals(Object obj)
    {
      return attrset.equals(obj);
    }

    public Attribute get(Class interfaceName)
    {
      return attrset.get(interfaceName);
    }

    public int hashCode()
    {
      return attrset.hashCode();
    }

    public boolean isEmpty()
    {
      return attrset.isEmpty();
    }

    public boolean remove(Class category)
    {
      throw new UnmodifiableSetException();
    }

    public boolean remove(Attribute attribute)
    {
      throw new UnmodifiableSetException();
    }

    public int size()
    {
      return attrset.size();
    }

    public Attribute[] toArray()
    {
      return attrset.toArray();
    }
  }

  private static class UnmodifiableDocAttributeSet
    extends UnmodifiableAttributeSet
    implements DocAttributeSet, Serializable
  {
    public UnmodifiableDocAttributeSet(DocAttributeSet attributeSet)
    {
      super(attributeSet);
    }
  }

  private static class UnmodifiablePrintJobAttributeSet
    extends UnmodifiableAttributeSet
    implements PrintJobAttributeSet, Serializable
  {
    public UnmodifiablePrintJobAttributeSet(PrintJobAttributeSet attributeSet)
    {
      super(attributeSet);
    }
  }

  private static class UnmodifiablePrintRequestAttributeSet
    extends UnmodifiableAttributeSet
    implements PrintRequestAttributeSet, Serializable
  {
    public UnmodifiablePrintRequestAttributeSet(PrintRequestAttributeSet attributeSet)
    {
      super(attributeSet);
    }
  }

  private static class UnmodifiablePrintServiceAttributeSet
    extends UnmodifiableAttributeSet
    implements PrintServiceAttributeSet, Serializable
  {
    public UnmodifiablePrintServiceAttributeSet(PrintServiceAttributeSet attributeSet)
    {
      super(attributeSet);
    }
  }

  private static class SynchronizedAttributeSet
    implements AttributeSet, Serializable
  {
    private AttributeSet attrset;

    public SynchronizedAttributeSet(AttributeSet attributeSet)
    {
      if (attributeSet == null)
        throw new NullPointerException("attributeSet may not be null");

      attrset = attributeSet;
    }

    public synchronized boolean add(Attribute attribute)
    {
      return attrset.add(attribute);
    }

    public synchronized boolean addAll(AttributeSet attributes)
    {
      return attrset.addAll(attributes);
    }

    public synchronized void clear()
    {
      attrset.clear();
    }

    public synchronized boolean containsKey(Class category)
    {
      return attrset.containsKey(category);
    }

    public synchronized boolean containsValue(Attribute attribute)
    {
      return attrset.containsValue(attribute);
    }

    public synchronized boolean equals(Object obj)
    {
      return attrset.equals(obj);
    }

    public synchronized Attribute get(Class interfaceName)
    {
      return attrset.get(interfaceName);
    }

    public synchronized int hashCode()
    {
      return attrset.hashCode();
    }

    public synchronized boolean isEmpty()
    {
      return attrset.isEmpty();
    }

    public synchronized boolean remove(Class category)
    {
      return attrset.remove(category);
    }

    public synchronized boolean remove(Attribute attribute)
    {
      return attrset.remove(attribute);
    }

    public synchronized int size()
    {
      return attrset.size();
    }

    public synchronized Attribute[] toArray()
    {
      return attrset.toArray();
    }
  }

  private static class SynchronizedDocAttributeSet
    extends SynchronizedAttributeSet
    implements DocAttributeSet, Serializable
  {
    public SynchronizedDocAttributeSet(DocAttributeSet attributeSet)
    {
      super(attributeSet);
    }
  }

  private static class SynchronizedPrintJobAttributeSet
    extends SynchronizedAttributeSet
    implements PrintJobAttributeSet, Serializable
  {
    public SynchronizedPrintJobAttributeSet(PrintJobAttributeSet attributeSet)
    {
      super(attributeSet);
    }
  }

  private static class SynchronizedPrintRequestAttributeSet
    extends SynchronizedAttributeSet
    implements PrintRequestAttributeSet, Serializable
  {
    public SynchronizedPrintRequestAttributeSet(PrintRequestAttributeSet attributeSet)
    {
      super(attributeSet);
    }
  }

  private static class SynchronizedPrintServiceAttributeSet
    extends SynchronizedAttributeSet
    implements PrintServiceAttributeSet, Serializable
  {
    public SynchronizedPrintServiceAttributeSet(PrintServiceAttributeSet attributeSet)
    {
      super(attributeSet);
    }
  }

  /**
   * Returns a synchronized view of the given attribute set.
   *
   * @param attributeSet the set to synchronize.
   * @return The sychronized attribute set.
   */
  public static AttributeSet synchronizedView(AttributeSet attributeSet)
  {
    return new SynchronizedAttributeSet(attributeSet);
  }

  /**
   * Returns a synchronized view of the given attribute set.
   *
   * @param attributeSet the set to synchronize.
   * @return The sychronized attribute set.
   */
  public static DocAttributeSet synchronizedView(DocAttributeSet attributeSet)
  {
    return new SynchronizedDocAttributeSet(attributeSet);
  }

  /**
   * Returns a synchronized view of the given attribute set.
   *
   * @param attributeSet the set to synchronize.
   * @return The sychronized attribute set.
   */
  public static PrintJobAttributeSet synchronizedView(PrintJobAttributeSet attributeSet)
  {
    return new SynchronizedPrintJobAttributeSet(attributeSet);
  }

  /**
   * Returns a synchronized view of the given attribute set.
   *
   * @param attributeSet the set to synchronize.
   * @return The sychronized attribute set.
   */
  public static PrintRequestAttributeSet synchronizedView(PrintRequestAttributeSet attributeSet)
  {
    return new SynchronizedPrintRequestAttributeSet(attributeSet);
  }

  /**
   * Returns a synchronized view of the given attribute set.
   *
   * @param attributeSet the set to synchronize.
   * @return The sychronized attribute set.
   */
  public static PrintServiceAttributeSet synchronizedView(PrintServiceAttributeSet attributeSet)
  {
    return new SynchronizedPrintServiceAttributeSet(attributeSet);
  }

  /**
   * Returns an unmodifiable view of the given attribute set.
   *
   * @param attributeSet the set to make unmodifiable.
   * @return The unmodifiable attribute set.
   */
  public static AttributeSet unmodifiableView(AttributeSet attributeSet)
  {
    return new UnmodifiableAttributeSet(attributeSet);
  }

  /**
   * Returns an unmodifiable view of the given attribute set.
   *
   * @param attributeSet the set to make unmodifiable.
   * @return The unmodifiable attribute set.
   */
  public static DocAttributeSet unmodifiableView(DocAttributeSet attributeSet)
  {
    return new UnmodifiableDocAttributeSet(attributeSet);
  }

  /**
   * Returns an unmodifiable view of the given attribute set.
   *
   * @param attributeSet the set to make unmodifiable.
   * @return The unmodifiable attribute set.
   */
  public static PrintJobAttributeSet unmodifiableView(PrintJobAttributeSet attributeSet)
  {
    return new UnmodifiablePrintJobAttributeSet(attributeSet);
  }

  /**
   * Returns an unmodifiable view of the given attribute set.
   *
   * @param attributeSet the set to make unmodifiable.
   * @return The unmodifiable attribute set.
   */
  public static PrintRequestAttributeSet unmodifiableView(PrintRequestAttributeSet attributeSet)
  {
    return new UnmodifiablePrintRequestAttributeSet(attributeSet);
  }

  /**
   * Returns an unmodifiable view of the given attribute set.
   *
   * @param attributeSet the set to make unmodifiable.
   * @return The unmodifiable attribute set.
   */
  public static PrintServiceAttributeSet unmodifiableView(PrintServiceAttributeSet attributeSet)
  {
    return new UnmodifiablePrintServiceAttributeSet(attributeSet);
  }

  /**
   * Verifies that the given object is a <code>Class</code> that
   * implements the given interface name and returns it casted.
   *
   * @param object the object to test.
   * @param interfaceName the <code>Class</code> to verify against.
   * @return object casted to <code>Class</code>
   *
   * @exception ClassCastException if object is not a <code>Class</code>
   * that implements interfaceName
   * @exception NullPointerException if object is null
   */
  public static Class<?> verifyAttributeCategory(Object object,
                                                 Class<?> interfaceName)
  {
    if (object == null)
      throw new NullPointerException("object may not be null");

    Class clazz = (Class) object;

    if (interfaceName.isAssignableFrom(clazz))
      return clazz;

    throw new ClassCastException();
  }

  /**
   * Verifies that the given object is an attribute of the given interface.
   * and returns it casted to the interface type.
   *
   * @param object the object to test.
   * @param interfaceName the <code>Class</code> to verify against.
   * @return the object casted to <code>Attribute</code>
   *
   * @exception ClassCastException if object is no instance of interfaceName.
   * @exception NullPointerException if object is null
   */
  public static Attribute verifyAttributeValue(Object object,
                                               Class<?> interfaceName)
  {
    if (object == null)
      throw new NullPointerException("object may not be null");

    if (interfaceName.isInstance(object))
      return (Attribute) object;

    throw new ClassCastException();
  }

  /**
   * Verifies that the category of attribute is equals to the given category
   * class.
   *
   * @param category the category to test.
   * @param attribute the attribute to verify.
   *
   * @exception IllegalArgumentException if the categories are not equal
   * @exception NullPointerException if category is null
   */
  public static void verifyCategoryForValue(Class<?> category,
                                            Attribute attribute)
  {
    if (category == null || attribute == null)
      throw new NullPointerException("category or attribute may not be null");

    if (!category.equals(attribute.getCategory()))
      throw new IllegalArgumentException
        ("category of attribute not equal to category");
  }
}