Synchronized_c.java

package polyglot.ext.jl.ast;

import polyglot.ast.*;
import polyglot.types.*;
import polyglot.visit.*;
import polyglot.util.*;
import java.util.*;

/**
 * An immutable representation of a Java language <code>synchronized</code>
 * block. Contains an expression being tested and a statement to be executed
 * while the expression is <code>true</code>.
 */
public class Synchronized_c extends Stmt_c implements Synchronized
{
    protected Expr expr;
    protected Block body;

    public Synchronized_c(Position pos, Expr expr, Block body) {
	super(pos);
	this.expr = expr;
	this.body = body;
    }

    /** Get the expression to synchronize. */
    public Expr expr() {
	return this.expr;
    }

    /** Set the expression to synchronize. */
    public Synchronized expr(Expr expr) {
	Synchronized_c n = (Synchronized_c) copy();
	n.expr = expr;
	return n;
    }

    /** Get the body of the statement. */
    public Block body() {
	return this.body;
    }

    /** Set the body of the statement. */
    public Synchronized body(Block body) {
	Synchronized_c n = (Synchronized_c) copy();
	n.body = body;
	return n;
    }

    /** Reconstruct the statement. */
    protected Synchronized_c reconstruct(Expr expr, Block body) {
	if (expr != this.expr || body != this.body) {
	    Synchronized_c n = (Synchronized_c) copy();
	    n.expr = expr;
	    n.body = body;
	    return n;
	}

	return this;
    }

    /** Visit the children of the statement. */
    public Node visitChildren(NodeVisitor v) {
	Expr expr = (Expr) visitChild(this.expr, v);
	Block body = (Block) visitChild(this.body, v);
	return reconstruct(expr, body);
    }

    /** Type check the statement. */
    public Node typeCheck(TypeChecker tc) throws SemanticException {
	TypeSystem ts = tc.typeSystem();

	if (! ts.isSubtype(expr.type(), ts.Object()) ) {
	     throw new SemanticException(
		 "Cannot synchronize on an expression of type \"" +
		 expr.type() + "\".", expr.position());
	}

	return this;
    }

    public Type childExpectedType(Expr child, AscriptionVisitor av) {
        TypeSystem ts = av.typeSystem();

        if (child == expr) {
            return ts.Object();
        }

        return child.type();
    }

    public String toString() {
	return "synchronized (" + expr + ") { ... }";
    }

    /** Write the statement to an output file. */
    public void prettyPrint(CodeWriter w, PrettyPrinter tr) {
	w.write("synchronized (");
	printBlock(expr, w, tr);
	w.write(") ");
	printSubStmt(body, w, tr);
    }

    public Term entry() {
        return expr.entry();
    }

    public List acceptCFG(CFGBuilder v, List succs) {
        v.visitCFG(expr, body.entry());
        v.visitCFG(body, this);
        return succs;
    }
}