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Evaluating Software Design Patterns — the "Gang of Four" patterns implemented in Java 6 |
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java.lang.Object dk.rode.thesis.interpreter.AbstractExpression<E> dk.rode.thesis.interpreter.BinaryExpression<Object,Boolean> dk.rode.thesis.interpreter.EqualExpression
@Participant(value="NonTerminalExpression") public class EqualExpression
An equal expression can determine if the result of evaluating two expressions is equal or not, regardless of types.
CompareExpression
,
NotExpression
,
AndExpression
,
OrExpression
Nested Class Summary |
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Nested classes/interfaces inherited from interface dk.rode.thesis.interpreter.Expression |
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Expression.SymbolIdiom |
Field Summary |
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Fields inherited from class dk.rode.thesis.interpreter.BinaryExpression |
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first, second |
Constructor Summary | |
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EqualExpression(EqualExpression expression)
Copy constructor. |
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EqualExpression(Expression<?> first,
Expression<?> second)
Constructor. |
Method Summary | |
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String |
asSymbol(Context context)
Returns x == y , where x is the symbolic
representation of the first expression operand and y
of the the second. |
EqualExpression |
copy()
Copies this expression. |
Boolean |
evaluate(Context context)
Evaluates this expression and returns the result. |
String |
name()
The stand-alone symbol name for this expression. |
Methods inherited from class dk.rode.thesis.interpreter.BinaryExpression |
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asSymbol, asSymbol, operands, toString |
Methods inherited from class dk.rode.thesis.interpreter.AbstractExpression |
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contains, equals, hashCode |
Methods inherited from class java.lang.Object |
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clone, finalize, getClass, notify, notifyAll, wait, wait, wait |
Methods inherited from interface dk.rode.thesis.interpreter.Expression |
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contains, operands, toString |
Constructor Detail |
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public EqualExpression(EqualExpression expression)
expression
- The expression to copy; cannot be null.
NullPointerException
- If expression
is null.public EqualExpression(Expression<?> first, Expression<?> second)
first
- The first expression operand; cannot be null.second
- The second expression operand; cannot be null.
NullPointerException
- If either expression is null.Method Detail |
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public String asSymbol(Context context) throws ExpressionException
x == y
, where x
is the symbolic
representation of the first expression operand and y
of the the second.
asSymbol
in interface Expression<Boolean>
context
- The context to use; never null.
ExpressionException
- If the symbol cannot be generated.Expression.contains(Expression)
public EqualExpression copy()
Expression
Unlike Expression.asSymbol(Context)
, copying
cannot handle cyclic expression references!
copy
in interface Expression<Boolean>
copy
in interface Copyable<Expression<Boolean>>
public Boolean evaluate(Context context) throws ExpressionException
Expression
There is no guarantee that the evaluation of this expression will terminate!
evaluate
in interface Expression<Boolean>
context
- The context to use; cannot be null.
ExpressionException
- If the evaluation fails.public final String name()
Expression
name
in interface Expression<Boolean>
equal
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Gunni Rode / rode.dk | ||||||||
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