com.sun.msv.grammar.OtherExp Maven / Gradle / Ivy
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*/
package com.sun.msv.grammar;
/**
* Base class for application-specific AGM annotation.
*
*
* This primitive has no meaning to MSV. For example, the following expression
*
* Expression exp = new OtherExp( pool.createSequence(a,b) );
*
* is treated as if MSV sees the following, OtherExp-less expression:
*
* Expression exp = pool.createSequence(a,b);
*
*
*
* By using this "transparency", application can implement derived classes
* of OtherExp and add application-specific information to AGM.
*
*
* For example, you can implement AnnotationInfoExp class that derives
* OtherExp and introduces "documentation" field.
* Then you'll write a customized XMLSchemaReader that
* parses <annotation> tag and mix AnnotationInfoExp into an AGM.
* Your application can then examine it and do some useful things.
*
*
* Those application-specific information added through OtherExp are completely
* ignored by MSV. So the annotated AGM can still be used just like anormal AGM.
*
*
* @author Kohsuke KAWAGUCHI
*/
public class OtherExp extends Expression {
/**
* returns the string which will be used by ExpressionPrinter
* to print this expression.
*/
public String printName() {
String className = this.getClass().getName();
int idx = className.lastIndexOf('.');
if(idx>=0) className = className.substring(idx+1);
return className;
}
/**
* child expression.
*/
public Expression exp;
public OtherExp() {
}
protected final int calcHashCode() {
return System.identityHashCode(this);
}
public OtherExp( Expression exp ) {
this();
this.exp = exp;
}
public boolean equals( Object o ) {
return this==o;
}
protected boolean calcEpsilonReducibility() {
if(exp==null)
// // actual expression is not supplied yet.
// // actual definition of the referenced expression must be supplied
// // before any computation over the grammar.
// throw new Error(); // assertion failed.
return false;
// this method can be called while parsing a grammar.
// in that case, epsilon reducibility is just used for approximation.
// therefore we can safely return false.
return exp.isEpsilonReducible();
}
// derived class must be able to behave as a ReferenceExp
public final Object visit( ExpressionVisitor visitor ) { return visitor.onOther(this); }
public final Expression visit( ExpressionVisitorExpression visitor ){ return visitor.onOther(this); }
public final boolean visit( ExpressionVisitorBoolean visitor ) { return visitor.onOther(this); }
public final void visit( ExpressionVisitorVoid visitor ) { visitor.onOther(this); }
// serialization support
private static final long serialVersionUID = 1;
}