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 * Licensed to the Apache Software Foundation (ASF) under one or more
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package com.sun.org.apache.xalan.internal.xsltc.compiler;

import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;

Author:
Jacek Ambroziak, Santiago Pericas-Geertsen/**
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 */
public abstract class Pattern extends Expression {
    
Returns the type of a pattern, which is always a NodeType.
A NodeType has a number of subtypes defined by
NodeType._type corresponding to each type of node.
/**
     * Returns the type of a pattern, which is always a <code>NodeType</code>.
     * A <code>NodeType</code> has a number of subtypes defined by
     * <code>NodeType._type</code> corresponding to each type of node.
     */
    public abstract Type typeCheck(SymbolTable stable) throws TypeCheckError;

    
Translate this node into JVM bytecodes. Patterns are translated as
boolean expressions with true/false lists. Before calling
translate on a pattern, make sure that the node being
matched is on top of the stack. After calling translate,
make sure to backpatch both true and false lists. True lists are the
default, in the sense that they always "fall through". If this is not the intended semantics (e.g., see AlternativePattern.translate) then a GOTO must be appended to the instruction list after calling translate.
/**
     * Translate this node into JVM bytecodes. Patterns are translated as
     * boolean expressions with true/false lists. Before calling
     * <code>translate</code> on a pattern, make sure that the node being
     * matched is on top of the stack. After calling <code>translate</code>,
     * make sure to backpatch both true and false lists. True lists are the
     * default, in the sense that they always <em>"fall through"</em>. If this
     * is not the intended semantics (e.g., see
     * {@link com.sun.org.apache.xalan.internal.xsltc.compiler.AlternativePattern#translate})
     * then a GOTO must be appended to the instruction list after calling
     * <code>translate</code>.
     */
    public abstract void translate(ClassGenerator classGen,
                                   MethodGenerator methodGen);

    
Returns the priority of this pattern (section 5.5 in the XSLT spec).
/**
     * Returns the priority of this pattern (section 5.5 in the XSLT spec).
     */
    public abstract double getPriority();
}