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ObjectConstantExpression
public class ConstantExpression
The Expression class is not immutable!
However we do have a need for immutable literal expressions when defining our API for SLD, and any other standards based on Expression.
Field Summary | |
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static ConstantExpression |
BLACK
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static ConstantExpression |
NULL
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static ConstantExpression |
ONE
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static ConstantExpression |
TWO
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static ConstantExpression |
UNNAMED
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static ConstantExpression |
ZERO
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Fields inherited from interface ExpressionType |
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ATTRIBUTE, ATTRIBUTE_DOUBLE, ATTRIBUTE_GEOMETRY, ATTRIBUTE_INTEGER, ATTRIBUTE_STRING, ATTRIBUTE_UNDECLARED, FUNCTION, LITERAL_DOUBLE, LITERAL_GEOMETRY, LITERAL_INTEGER, LITERAL_LONG, LITERAL_STRING, LITERAL_UNDECLARED, MATH_ADD, MATH_DIVIDE, MATH_MULTIPLY, MATH_SUBTRACT |
Fields inherited from interface Expression |
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NIL |
Constructor Summary | |
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protected |
ConstantExpression(Object value)
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protected |
ConstantExpression(short type,
Object value)
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Method Summary | ||
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Object |
accept(ExpressionVisitor visitor,
Object extraData)
Accepts a visitor. |
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void |
accept(FilterVisitor visitor)
Deprecated. use accept(ExpressionVisitor, Object) . |
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protected Object |
clone()
|
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static ConstantExpression |
color(Color color)
Encode provided color as a String |
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static ConstantExpression |
constant(double number)
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static ConstantExpression |
constant(int number)
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static ConstantExpression |
constant(Object value)
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boolean |
equals(Object obj)
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Object |
evaluate(Object object)
Evaluates the given expression based on the content of the given object. |
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evaluate(Object object,
Class<T> context)
Evaluates the given expressoin based on the content of the given object and the context type. |
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Object |
evaluate(SimpleFeature feature)
Evaluates the expression against an instance of Feature . |
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Object |
getLiteral()
Deprecated. use getValue() |
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short |
getType()
Returns the literal type. |
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Object |
getValue()
Returns the constant value held by this object. |
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Object |
getValue(SimpleFeature feature)
Deprecated. use #evaluate(Feature) |
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int |
hashCode()
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void |
setLiteral(Object literal)
Deprecated. use setValue(Object) |
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void |
setValue(Object constant)
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String |
toString()
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Methods inherited from class Object |
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finalize, getClass, notify, notifyAll, wait, wait, wait |
Field Detail |
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public static final ConstantExpression NULL
public static final ConstantExpression BLACK
public static final ConstantExpression ZERO
public static final ConstantExpression ONE
public static final ConstantExpression TWO
public static final ConstantExpression UNNAMED
Constructor Detail |
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protected ConstantExpression(Object value)
protected ConstantExpression(short type, Object value)
Method Detail |
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public final void setLiteral(Object literal) throws IllegalFilterException
setValue(Object)
LiteralExpression
setLiteral
in interface LiteralExpression
literal
- The literal to store inside this expression.
IllegalFilterException
- This literal type is not in scope.public final Object getValue(SimpleFeature feature)
#evaluate(Feature)
LiteralExpression
getValue
in interface LiteralExpression
feature
- Required by the interface but not used.
public Object evaluate(SimpleFeature feature)
Expression
Feature
.
feature
- The feature being evaluated.
public Object evaluate(Object object)
Expression
evaluate
in interface Expression
public <T> T evaluate(Object object, Class<T> context)
Expression
The context
parameter is used to control the type of the
result of the expression. A particular expression may not be able to evaluate
to an instance of context
. Therefore to be safe calling code
should do a null check on the return value of this method, and call Expression.evaluate(Object)
if neccessary. Example:
Object input = ...; String result = expression.evaluate( input, String.class ); if ( result == null ) { result = expression.evalute( input ).toString(); } ...
Implementations that can not return a result as an instance of context
should return null
.
evaluate
in interface Expression
T
- The type of the returned object.object
- The object to evaluate the expression against.context
- The type of the resulting value of the expression.
context
.public Object getValue()
Literal
getValue
in interface Literal
public void setValue(Object constant)
public short getType()
LiteralExpression
getType
in interface LiteralExpression
public final Object getLiteral()
getValue()
LiteralExpression
getLiteral
in interface LiteralExpression
public void accept(FilterVisitor visitor)
accept(ExpressionVisitor, Object)
.
Expression
visitor
- The visitor which requires access to this filter, the
method must call visitor.visit(this);public Object accept(ExpressionVisitor visitor, Object extraData)
Expression
return visitor.visit(this, extraData);
accept
in interface Expression
protected Object clone() throws CloneNotSupportedException
clone
in class Object
CloneNotSupportedException
public boolean equals(Object obj)
equals
in class Object
public int hashCode()
hashCode
in class Object
public String toString()
toString
in class Object
public static ConstantExpression color(Color color)
public static ConstantExpression constant(double number)
public static ConstantExpression constant(int number)
public static ConstantExpression constant(Object value)
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