ec.rule

Class Rule

java.lang.Object

ec.rule.Rule

All Implemented Interfaces:

Prototype, Setup, java.io.Serializable, java.lang.Cloneable, java.lang.Comparable

public abstract class Rule
extends java.lang.Object
implements Prototype, java.lang.Comparable

Rule is an abstract class for describing rules. It is abstract because it is supposed to be extended by different classes modelling different kinds of rules. It provides the reset abstract method for randomizing the individual. It also provides the mutate function for mutating an individual rule It also provides the clone function for cloning the rule.

You will need to implement some kind of artificial ordering between rules in a ruleset using the Comparable interface, so the ruleset can be sorted in such a way that it can be compared with another ruleset for equality. You should also implement hashCode and equals in such a way that they aren't based on pointer information, but on actual internal features.

Every rule points to a RuleConstraints which handles information that Rule shares with all the other Rules in a RuleSet.

In addition to serialization for checkpointing, Rules may read and write themselves to streams in three ways.

• writeRule(...,DataOutput)/readRule(...,DataInput) This method transmits or receives a Rule in binary. It is the most efficient approach to sending Rules over networks, etc. The default versions of writeRule/readRule throw errors. You don't need to implement them if you don't plan on using read/writeRule.
• printRule(...,PrintWriter)/readRule(...,LineNumberReader) This approach transmits or receives a Rule in text encoded such that the Rule is largely readable by humans but can be read back in 100% by ECJ as well. To do this, these methods will typically encode numbers using the ec.util.Code class. These methods are mostly used to write out populations to files for inspection, slight modification, then reading back in later on. readRule reads in a line, then calls readRuleFromString on that line. You are responsible for implementing readRuleFromString: the Code class is there to help you. The default version throws an error if called. printRule calls printRuleToString and printlns the resultant string. You are responsible for implementing the printRuleToString method in such a way that readRuleFromString can read back in the Rule println'd with printRuleToString. The default form of printRuleToString() simply calls toString() by default. You might override printRuleToString() to provide better information. You are not required to implement these methods, but without them you will not be able to write Rules to files in a simultaneously computer- and human-readable fashion.
• printRuleForHumans(...,PrintWriter) This approach prints a Rule in a fashion intended for human consumption only. printRuleForHumans calls printRuleToStringForHumans() and printlns the resultant string. The default form of this method just returns the value of toString(). You may wish to override this to provide more information instead. You should handle one of these methods properly to ensure Rules can be printed by ECJ.

Parameters

base.constraints string

(name of the rule constraint)

Default Base
rule.rule

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
byte	constraints An index to a RuleConstraints
static java.lang.String	P_CONSTRAINTS
static java.lang.String	P_RULE

Constructor Summary

Constructors

Constructor and Description
Rule()

Method Summary

Modifier and Type	Method and Description
java.lang.Object	clone() Creates a new individual cloned from a prototype, and suitable to begin use in its own evolutionary context.
abstract int	compareTo(java.lang.Object o) This function replaces the old gt and lt functions that Rule used to require as it implemented the SortComparator interface.
RuleConstraints	constraints(RuleInitializer initializer)
Parameter	defaultBase() Returns the default base for this prototype.
boolean	equals(java.lang.Object other) Unlike the standard form for Java, this function should return true if this rule is "genetically identical" to the other rule.
abstract int	hashCode() Rulerates a hash code for this rule -- the rule for this is that the hash code must be the same for two rules that are equal to each other genetically.
void	mutate(EvolutionState state, int thread) Mutate the rule.
void	printRule(EvolutionState state, int log) Prints the rule in a way that can be read by readRule().
void	printRule(EvolutionState state, int log, int verbosity) Deprecated. Verbosity no longer has an effect
void	printRule(EvolutionState state, java.io.PrintWriter writer) Prints the rule in a way that can be read by readRule().
void	printRuleForHumans(EvolutionState state, int log) Nice printing.
void	printRuleForHumans(EvolutionState state, int log, int verbosity) Deprecated. Verbosity no longer has an effect
java.lang.String	printRuleToString() Prints the rule to a string in a fashion readable by readRuleFromString.
java.lang.String	printRuleToString(EvolutionState state) Deprecated.
java.lang.String	printRuleToStringForHumans() Nice printing to a string.
void	readRule(EvolutionState state, java.io.DataInput dataInput) Override this if you need to read rules in from a binary stream
void	readRule(EvolutionState state, java.io.LineNumberReader reader) Reads a rule printed by printRule(...).
void	readRuleFromString(java.lang.String string, EvolutionState state) Reads a rule from a string, which may contain a final '\n'.
abstract void	reset(EvolutionState state, int thread) The reset method randomly reinitializes the rule.
void	setup(EvolutionState state, Parameter base) Sets up the object by reading it from the parameters stored in state, built off of the parameter base base.
void	writeRule(EvolutionState state, java.io.DataOutput dataOutput) Override this if you need to write rules out to a binary stream

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, toString, wait, wait, wait

Field Detail

P_RULE

public static final java.lang.String P_RULE

See Also:

Constant Field Values

P_CONSTRAINTS

public static final java.lang.String P_CONSTRAINTS

See Also:

Constant Field Values

constraints

public byte constraints

An index to a RuleConstraints

Constructor Detail

Rule

public Rule()

Method Detail

constraints

public final RuleConstraints constraints(RuleInitializer initializer)

hashCode

public abstract int hashCode()

Rulerates a hash code for this rule -- the rule for this is that the hash code must be the same for two rules that are equal to each other genetically.

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object other)

Unlike the standard form for Java, this function should return true if this rule is "genetically identical" to the other rule. The default calls compareTo()

Overrides:

equals in class java.lang.Object

reset

public abstract void reset(EvolutionState state,
                           int thread)

The reset method randomly reinitializes the rule.

mutate

public void mutate(EvolutionState state,
                   int thread)

Mutate the rule. The default form just resets the rule.

printRuleForHumans

public void printRuleForHumans(EvolutionState state,
                               int log)

Nice printing. The default form simply calls printRuleToStringForHumans and prints the result, but you might want to override this.

printRuleForHumans

public void printRuleForHumans(EvolutionState state,
                               int log,
                               int verbosity)

Deprecated. Verbosity no longer has an effect

Nice printing. The default form simply calls printRuleToStringForHumans and prints the result, but you might want to override this.

printRuleToStringForHumans

public java.lang.String printRuleToStringForHumans()

Nice printing to a string. The default form calls toString().

printRuleToString

public java.lang.String printRuleToString(EvolutionState state)

Deprecated.

Prints the rule to a string in a fashion readable by readRuleFromString. The default form calls printRuleToString().

printRuleToString

public java.lang.String printRuleToString()

Prints the rule to a string in a fashion readable by readRuleFromString. The default form simply calls toString() -- you should just override toString() if you don't need the EvolutionState.

readRuleFromString

public void readRuleFromString(java.lang.String string,
                               EvolutionState state)

Reads a rule from a string, which may contain a final '\n'. Override this method. The default form generates an error.

printRule

public void printRule(EvolutionState state,
                      int log)

Prints the rule in a way that can be read by readRule(). The default form simply calls printRuleToString(state). Override this rule to do custom writing to the log, or just override printRuleToString(...), which is probably easier to do.

printRule

public void printRule(EvolutionState state,
                      int log,
                      int verbosity)

Deprecated. Verbosity no longer has an effect

Prints the rule in a way that can be read by readRule(). The default form simply calls printRuleToString(state). Override this rule to do custom writing to the log, or just override printRuleToString(...), which is probably easier to do.

printRule

public void printRule(EvolutionState state,
                      java.io.PrintWriter writer)

Prints the rule in a way that can be read by readRule(). The default form simply calls printRuleToString(state). Override this rule to do custom writing, or just override printRuleToString(...), which is probably easier to do.

readRule

public void readRule(EvolutionState state,
                     java.io.LineNumberReader reader)
              throws java.io.IOException

Reads a rule printed by printRule(...). The default form simply reads a line into a string, and then calls readRuleFromString() on that line. Override this rule to do custom reading, or just override readRuleFromString(...), which is probably easier to do.

Throws:

java.io.IOException

writeRule

public void writeRule(EvolutionState state,
                      java.io.DataOutput dataOutput)
               throws java.io.IOException

Override this if you need to write rules out to a binary stream

Throws:

java.io.IOException

readRule

public void readRule(EvolutionState state,
                     java.io.DataInput dataInput)
              throws java.io.IOException

Override this if you need to read rules in from a binary stream

Throws:

java.io.IOException

defaultBase

public Parameter defaultBase()

Description copied from interface: Prototype

Returns the default base for this prototype. This should generally be implemented by building off of the static base() method on the DefaultsForm object for the prototype's package. This should be callable during setup(...).

Specified by:

defaultBase in interface Prototype

clone

public java.lang.Object clone()

Description copied from interface: Prototype

Creates a new individual cloned from a prototype, and suitable to begin use in its own evolutionary context.

Typically this should be a full "deep" clone. However, you may share certain elements with other objects rather than clone hem, depending on the situation:

• If you hold objects which are shared with other instances, don't clone them.
• If you hold objects which must be unique, clone them.
• If you hold objects which were given to you as a gesture of kindness, and aren't owned by you, you probably shouldn't clone them.
• DON'T attempt to clone: Singletons, Cliques, or Groups.
• Arrays are not cloned automatically; you may need to clone an array if you're not sharing it with other instances. Arrays have the nice feature of being copyable by calling clone() on them.

Implementations.

• If no ancestor of yours implements clone(), and you have no need to do clone deeply, and you are abstract, then you should not declare clone().
• If no ancestor of yours implements clone(), and you have no need to do clone deeply, and you are not abstract, then you should implement it as follows:

   public Object clone() 
       {
       try
           { 
           return super.clone();
           }
       catch ((CloneNotSupportedException e)
           { throw new InternalError(); } // never happens
       }
          

• If no ancestor of yours implements clone(), but you need to deep-clone some things, then you should implement it as follows:

   public Object clone() 
       {
       try
           { 
           MyObject myobj = (MyObject) (super.clone());
  
           // put your deep-cloning code here...
           }
       catch ((CloneNotSupportedException e)
           { throw new InternalError(); } // never happens
       return myobj;
       } 
          

• If an ancestor has implemented clone(), and you also need to deep clone some things, then you should implement it as follows:

   public Object clone() 
       { 
       MyObject myobj = (MyObject) (super.clone());
  
       // put your deep-cloning code here...
  
       return myobj;
       } 
          

Specified by:

clone in interface Prototype

Overrides:

clone in class java.lang.Object

setup

public void setup(EvolutionState state,
                  Parameter base)

Description copied from interface: Prototype

Sets up the object by reading it from the parameters stored in state, built off of the parameter base base. If an ancestor implements this method, be sure to call super.setup(state,base); before you do anything else.

For prototypes, setup(...) is typically called once for the prototype instance; cloned instances do not receive the setup(...) call. setup(...) may be called more than once; the only guarantee is that it will get called at least once on an instance or some "parent" object from which it was ultimately cloned.

Specified by:

setup in interface Prototype

Specified by:

setup in interface Setup

compareTo

public abstract int compareTo(java.lang.Object o)

This function replaces the old gt and lt functions that Rule used to require as it implemented the SortComparator interface. If you had implemented those old functions, you can simply implement this function as:

        public abstract int compareTo(Object o)
        {
        if (gt(this,o)) return 1;
        if (lt(this,o)) return -1;
        return 0;
        }
        

Specified by:

compareTo in interface java.lang.Comparable