mit.ai.techniques
Class PlanningProblem

java.lang.Object
  |
  +--mit.ai.techniques.PlanningProblem

public class PlanningProblem

extends java.lang.Object

This class represents the planning problem.

Field Summary

private Conjunction	goalConditions
private Conjunction	initialConditions Stop searching after this size.
static int	maxPlanDepth
private java.util.Vector	operators
private java.util.Hashtable	symbolTable

Constructor Summary

PlanningProblem(java.lang.String path)
Make a planning problem from a file.

Method Summary

void	addMaintenanceOperators(java.util.Vector operators) For each literal in the symbol table, make a new maintenance operator and add it to the vector of operators.
private void	assertString(java.io.StreamTokenizer st) Throw an exception if the current token isn't a string.
private void	eatLineFeeds(java.io.StreamTokenizer st) Be sure the next token is a line feed and eat it and any following line feeds.
java.util.Vector	getOperators() Return the operators.
java.util.Hashtable	getSymbolTable() Return the symbol table.
private void	makeSymbolTable(java.io.StreamTokenizer st) The first line of the input file is a list of all the propositions.
private Conjunction	readConjunction(java.io.StreamTokenizer st) Read a conjunction from the current line of the input file.
private Operator	readOperator(java.io.StreamTokenizer st) An operator has a name on one line, then the next line represents a conjunction of preconditions and the next line represents a conjunction of effects.
private java.util.Vector	readOperators(java.io.StreamTokenizer st) Read in operators until we hit the end of the file.
java.lang.String	toString() Create a string representing the problem.

Methods inherited from class java.lang.Object

, clone, equals, finalize, getClass, hashCode, notify, notifyAll, registerNatives, wait, wait, wait

Field Detail

maxPlanDepth

public static int maxPlanDepth

initialConditions

private Conjunction initialConditions

Stop searching after this size.

goalConditions

private Conjunction goalConditions

operators

private java.util.Vector operators

symbolTable

private java.util.Hashtable symbolTable

Constructor Detail

PlanningProblem

public PlanningProblem(java.lang.String path)

Make a planning problem from a file. Format is this: First, on a single line, delimited by spaces, all of the proposition names are listed. Then, on a single line, the initial state is listed. Negated propositions are represented by !name. On the next line, the goal is listed. The remainder of the file holds the operators. Each one takes three lines: name, preconds, effects.

Method Detail

makeSymbolTable

private void makeSymbolTable(java.io.StreamTokenizer st)
                      throws java.io.IOException

The first line of the input file is a list of all the propositions. For each proposition, make a positive and a negative literal. The symbolTable will map the name "p" into the positive literal and the string "!p" into the negative literal. Consume trailing line feeds.

readConjunction

private Conjunction readConjunction(java.io.StreamTokenizer st)
                             throws java.io.IOException

Read a conjunction from the current line of the input file. Assume the first token is waiting for us. Consume the final line feeds.

readOperators

private java.util.Vector readOperators(java.io.StreamTokenizer st)
                                throws java.io.IOException

Read in operators until we hit the end of the file. Assume the first token is waiting for us.

readOperator

private Operator readOperator(java.io.StreamTokenizer st)
                       throws java.io.IOException

An operator has a name on one line, then the next line represents a conjunction of preconditions and the next line represents a conjunction of effects. Assume that the first token has been read. Leaves first token of next thing in ttype.

eatLineFeeds

private void eatLineFeeds(java.io.StreamTokenizer st)
                   throws java.io.IOException

Be sure the next token is a line feed and eat it and any following line feeds.

assertString

private void assertString(java.io.StreamTokenizer st)

Throw an exception if the current token isn't a string.

addMaintenanceOperators

public void addMaintenanceOperators(java.util.Vector operators)

For each literal in the symbol table, make a new maintenance operator and add it to the vector of operators.

getOperators

public java.util.Vector getOperators()

Return the operators.

getSymbolTable

public java.util.Hashtable getSymbolTable()

Return the symbol table.

toString

public java.lang.String toString()

Create a string representing the problem.

Overrides:

toString in class java.lang.Object