Class HashAttributeSet provides an AttributeSet implementation with characteristics of a hash map.

@author
Alan Kaminsky
Construct a new, empty attribute set.
Construct a new attribute set, initially populated with the given attribute.
Parameters
attributeAttribute value to add to the set.
Throws
NullPointerException (unchecked exception) Thrown if attribute is null.
Construct a new attribute set, initially populated with the values from the given array. The new attribute set is populated by adding the elements of attributes array to the set in sequence, starting at index 0. Thus, later array elements may replace earlier array elements if the array contains duplicate attribute values or attribute categories.
Parameters
attributesArray of attribute values to add to the set. If null, an empty attribute set is constructed.
Throws
NullPointerException (unchecked exception) Thrown if any element of attributes is null.
Construct a new attribute set, initially populated with the values from the given set.
Parameters
attributesSet of attributes from which to initialise this set. If null, an empty attribute set is constructed.
Adds the specified attribute to this attribute set if it is not already present, first removing any existing value in the same attribute category as the specified attribute value.
Parameters
attributeAttribute value to be added to this attribute set.
Return
true if this attribute set changed as a result of the call, i.e., the given attribute value was not already a member of this attribute set.
Throws
NullPointerException (unchecked exception) Thrown if the attribute is null.
UnmodifiableSetException (unchecked exception) Thrown if this attribute set does not support the add() operation.
Adds all of the elements in the specified set to this attribute. The outcome is the same as if the = add(Attribute) operation had been applied to this attribute set successively with each element from the specified set. The behavior of the addAll(AttributeSet) operation is unspecified if the specified set is modified while the operation is in progress.

If the addAll(AttributeSet) operation throws an exception, the effect on this attribute set's state is implementation dependent; elements from the specified set before the point of the exception may or may not have been added to this attribute set.

Parameters
attributeswhose elements are to be added to this attribute set.
Return
true if this attribute set changed as a result of the call.
Throws
UnmodifiableSetException (Unchecked exception) Thrown if this attribute set does not support the addAll(AttributeSet) method.
NullPointerException (Unchecked exception) Thrown if some element in the specified set is null.
Removes all attributes from this attribute set.
Throws
UnmodifiableSetException (unchecked exception) Thrown if this attribute set does not support the clear() operation.
Returns true if this attribute set contains an attribute for the specified category.
Parameters
categorywhose presence in this attribute set is to be tested.
Return
true if this attribute set contains an attribute value for the specified category.
Returns true if this attribute set contains the given attribute value.
Parameters
attributeAttribute value whose presence in this attribute set is to be tested.
Return
true if this attribute set contains the given attribute value.
Compares the specified object with this attribute set for equality. Returns true if the given object is also an attribute set and the two attribute sets contain the same attribute category-attribute value mappings. This ensures that the equals() method works properly across different implementations of the AttributeSet interface.
Parameters
objectto be compared for equality with this attribute set.
Return
true if the specified object is equal to this attribute set.
Returns the attribute value which this attribute set contains in the given attribute category. Returns null if this attribute set does not contain any attribute value in the given attribute category.
Parameters
categoryAttribute category whose associated attribute value is to be returned. It must be a {@link java.lang.Class Class} that implements interface {@link Attribute Attribute}.
Return
The attribute value in the given attribute category contained in this attribute set, or null if this attribute set does not contain any attribute value in the given attribute category.
Throws
NullPointerException (unchecked exception) Thrown if the category is null.
ClassCastException (unchecked exception) Thrown if the category is not a {@link java.lang.Class Class} that implements interface {@link Attribute Attribute}.
Returns the runtime class of an object. That Class object is the object that is locked by static synchronized methods of the represented class.
Return
The java.lang.Class object that represents the runtime class of the object. The result is of type {@code Class} where X is the erasure of the static type of the expression on which getClass is called.
Returns the hash code value for this attribute set. The hash code of an attribute set is defined to be the sum of the hash codes of each entry in the AttributeSet. This ensures that t1.equals(t2) implies that t1.hashCode()==t2.hashCode() for any two attribute sets t1 and t2, as required by the general contract of Object.hashCode() .
Return
The hash code value for this attribute set.
Returns true if this attribute set contains no attributes.
Return
true if this attribute set contains no attributes.
Wakes up a single thread that is waiting on this object's monitor. If any threads are waiting on this object, one of them is chosen to be awakened. The choice is arbitrary and occurs at the discretion of the implementation. A thread waits on an object's monitor by calling one of the wait methods.

The awakened thread will not be able to proceed until the current thread relinquishes the lock on this object. The awakened thread will compete in the usual manner with any other threads that might be actively competing to synchronize on this object; for example, the awakened thread enjoys no reliable privilege or disadvantage in being the next thread to lock this object.

This method should only be called by a thread that is the owner of this object's monitor. A thread becomes the owner of the object's monitor in one of three ways:

  • By executing a synchronized instance method of that object.
  • By executing the body of a synchronized statement that synchronizes on the object.
  • For objects of type Class, by executing a synchronized static method of that class.

Only one thread at a time can own an object's monitor.

Throws
IllegalMonitorStateExceptionif the current thread is not the owner of this object's monitor.
Wakes up all threads that are waiting on this object's monitor. A thread waits on an object's monitor by calling one of the wait methods.

The awakened threads will not be able to proceed until the current thread relinquishes the lock on this object. The awakened threads will compete in the usual manner with any other threads that might be actively competing to synchronize on this object; for example, the awakened threads enjoy no reliable privilege or disadvantage in being the next thread to lock this object.

This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.

Throws
IllegalMonitorStateExceptionif the current thread is not the owner of this object's monitor.
Removes the specified attribute from this attribute set if present. If attribute is null, then remove() does nothing and returns false.
Parameters
attributeAttribute value to be removed from this attribute set.
Return
true if this attribute set changed as a result of the call, i.e., the given attribute value had been a member of this attribute set.
Throws
UnmodifiableSetException (unchecked exception) Thrown if this attribute set does not support the remove() operation.
Removes any attribute for this category from this attribute set if present. If category is null, then remove() does nothing and returns false.
Parameters
categoryAttribute category to be removed from this attribute set.
Return
true if this attribute set changed as a result of the call, i.e., the given attribute value had been a member of this attribute set.
Throws
UnmodifiableSetException (unchecked exception) Thrown if this attribute set does not support the remove() operation.
Returns the number of attributes in this attribute set. If this attribute set contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.
Return
The number of attributes in this attribute set.
Returns an array of the attributes contained in this set.
Return
the Attributes contained in this set as an array, zero length if the AttributeSet is empty.
Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())
 
Return
a string representation of the object.
Causes current thread to wait until another thread invokes the method or the method for this object. In other words, this method behaves exactly as if it simply performs the call wait(0).

The current thread must own this object's monitor. The thread releases ownership of this monitor and waits until another thread notifies threads waiting on this object's monitor to wake up either through a call to the notify method or the notifyAll method. The thread then waits until it can re-obtain ownership of the monitor and resumes execution.

As in the one argument version, interrupts and spurious wakeups are possible, and this method should always be used in a loop:

     synchronized (obj) {
         while (<condition does not hold>)
             obj.wait();
         ... // Perform action appropriate to condition
     }
 
This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.
Throws
IllegalMonitorStateExceptionif the current thread is not the owner of the object's monitor.
InterruptedExceptionif another thread interrupted the current thread before or while the current thread was waiting for a notification. The interrupted status of the current thread is cleared when this exception is thrown.
Causes current thread to wait until either another thread invokes the method or the method for this object, or a specified amount of time has elapsed.

The current thread must own this object's monitor.

This method causes the current thread (call it T) to place itself in the wait set for this object and then to relinquish any and all synchronization claims on this object. Thread T becomes disabled for thread scheduling purposes and lies dormant until one of four things happens:

  • Some other thread invokes the notify method for this object and thread T happens to be arbitrarily chosen as the thread to be awakened.
  • Some other thread invokes the notifyAll method for this object.
  • Some other thread interrupts thread T.
  • The specified amount of real time has elapsed, more or less. If timeout is zero, however, then real time is not taken into consideration and the thread simply waits until notified.
The thread T is then removed from the wait set for this object and re-enabled for thread scheduling. It then competes in the usual manner with other threads for the right to synchronize on the object; once it has gained control of the object, all its synchronization claims on the object are restored to the status quo ante - that is, to the situation as of the time that the wait method was invoked. Thread T then returns from the invocation of the wait method. Thus, on return from the wait method, the synchronization state of the object and of thread T is exactly as it was when the wait method was invoked.

A thread can also wake up without being notified, interrupted, or timing out, a so-called spurious wakeup. While this will rarely occur in practice, applications must guard against it by testing for the condition that should have caused the thread to be awakened, and continuing to wait if the condition is not satisfied. In other words, waits should always occur in loops, like this one:

     synchronized (obj) {
         while (<condition does not hold>)
             obj.wait(timeout);
         ... // Perform action appropriate to condition
     }
 
(For more information on this topic, see Section 3.2.3 in Doug Lea's "Concurrent Programming in Java (Second Edition)" (Addison-Wesley, 2000), or Item 50 in Joshua Bloch's "Effective Java Programming Language Guide" (Addison-Wesley, 2001).

If the current thread is interrupted by another thread while it is waiting, then an InterruptedException is thrown. This exception is not thrown until the lock status of this object has been restored as described above.

Note that the wait method, as it places the current thread into the wait set for this object, unlocks only this object; any other objects on which the current thread may be synchronized remain locked while the thread waits.

This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.

Parameters
timeoutthe maximum time to wait in milliseconds.
Throws
IllegalArgumentExceptionif the value of timeout is negative.
IllegalMonitorStateExceptionif the current thread is not the owner of the object's monitor.
InterruptedExceptionif another thread interrupted the current thread before or while the current thread was waiting for a notification. The interrupted status of the current thread is cleared when this exception is thrown.
Causes current thread to wait until another thread invokes the method or the method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.

This method is similar to the wait method of one argument, but it allows finer control over the amount of time to wait for a notification before giving up. The amount of real time, measured in nanoseconds, is given by:

 1000000*timeout+nanos

In all other respects, this method does the same thing as the method of one argument. In particular, wait(0, 0) means the same thing as wait(0).

The current thread must own this object's monitor. The thread releases ownership of this monitor and waits until either of the following two conditions has occurred:

  • Another thread notifies threads waiting on this object's monitor to wake up either through a call to the notify method or the notifyAll method.
  • The timeout period, specified by timeout milliseconds plus nanos nanoseconds arguments, has elapsed.

The thread then waits until it can re-obtain ownership of the monitor and resumes execution.

As in the one argument version, interrupts and spurious wakeups are possible, and this method should always be used in a loop:

     synchronized (obj) {
         while (<condition does not hold>)
             obj.wait(timeout, nanos);
         ... // Perform action appropriate to condition
     }
 
This method should only be called by a thread that is the owner of this object's monitor. See the notify method for a description of the ways in which a thread can become the owner of a monitor.
Parameters
timeoutthe maximum time to wait in milliseconds.
nanosadditional time, in nanoseconds range 0-999999.
Throws
IllegalArgumentExceptionif the value of timeout is negative or the value of nanos is not in the range 0-999999.
IllegalMonitorStateExceptionif the current thread is not the owner of this object's monitor.
InterruptedExceptionif another thread interrupted the current thread before or while the current thread was waiting for a notification. The interrupted status of the current thread is cleared when this exception is thrown.