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org.apache.derby.iapi.services.classfile
Class CONSTANT_Double_info  

java.lang.Object
  org.apache.derby.iapi.services.classfile.ConstantPoolEntry
      org.apache.derby.iapi.services.classfile.CONSTANT_Double_info

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final class CONSTANT_Double_info

extends ConstantPoolEntry

Double Constant - page 97 - Section 4.4.5

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Field Summary
private  double	value

 

Fields inherited from class org.apache.derby.iapi.services.classfile.ConstantPoolEntry

doubleSlot, index, tag

 

Constructor Summary
(package private)	CONSTANT_Double_info(double value)

 

Method Summary
(package private)  int	classFileSize()           Return an estimate of the size of the constant pool entry.
boolean	equals(java.lang.Object other)           Determine whether this Object is semantically equal to another Object.
int	hashCode()           Get a value that represents this Object, as uniquely as possible within the confines of an int.
(package private)  void	put(ClassFormatOutput out)

 

Methods inherited from class org.apache.derby.iapi.services.classfile.ConstantPoolEntry

doubleSlot, getI1, getI2, getIndex, getKey, getTag, setIndex

 

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

 

Field Detail

value

private final double value

Constructor Detail

CONSTANT_Double_info

CONSTANT_Double_info(double value)

Method Detail

hashCode

public int hashCode()

Description copied from class: java.lang.Object

Get a value that represents this Object, as uniquely as possible within the confines of an int.

There are some requirements on this method which subclasses must follow:

• Semantic equality implies identical hashcodes. In other words, if a.equals(b) is true, then a.hashCode() == b.hashCode() must be as well. However, the reverse is not necessarily true, and two objects may have the same hashcode without being equal.
• It must be consistent. Whichever value o.hashCode() returns on the first invocation must be the value returned on all later invocations as long as the object exists. Notice, however, that the result of hashCode may change between separate executions of a Virtual Machine, because it is not invoked on the same object.

Notice that since hashCode is used in java.util.Hashtable and other hashing classes, a poor implementation will degrade the performance of hashing (so don't blindly implement it as returning a constant!). Also, if calculating the hash is time-consuming, a class may consider caching the results.

The default implementation returns System.identityHashCode(this)

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classFileSize

int classFileSize()

Description copied from class: ConstantPoolEntry

Return an estimate of the size of the constant pool entry.

Specified by:

classFileSize in class ConstantPoolEntry

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put

void put(ClassFormatOutput out)
   throws java.io.IOException

Overrides:

put in class ConstantPoolEntry

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equals

public boolean equals(java.lang.Object other)

Description copied from class: java.lang.Object

Determine whether this Object is semantically equal to another Object.

There are some fairly strict requirements on this method which subclasses must follow:

• It must be transitive. If a.equals(b) and b.equals(c), then a.equals(c) must be true as well.
• It must be symmetric. a.equals(b) and b.equals(a) must have the same value.
• It must be reflexive. a.equals(a) must always be true.
• It must be consistent. Whichever value a.equals(b) returns on the first invocation must be the value returned on all later invocations.
• a.equals(null) must be false.
• It must be consistent with hashCode(). That is, a.equals(b) must imply a.hashCode() == b.hashCode(). The reverse is not true; two objects that are not equal may have the same hashcode, but that has the potential to harm hashing performance.

This is typically overridden to throw a java.lang.ClassCastException if the argument is not comparable to the class performing the comparison, but that is not a requirement. It is legal for a.equals(b) to be true even though a.getClass() != b.getClass(). Also, it is typical to never cause a java.lang.NullPointerException.

In general, the Collections API (java.util) use the equals method rather than the == operator to compare objects. However, java.util.IdentityHashMap is an exception to this rule, for its own good reasons.

The default implementation returns this == o.

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SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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