dataflow.src.org.checkerframework.dataflow.cfg.node.NullLiteralNode Maven / Gradle / Ivy

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The Checker Framework enhances Java’s type system to make it more powerful and useful. This lets software developers detect and prevent errors in their Java programs. The Checker Framework includes compiler plug-ins ("checkers") that find bugs or verify their absence. It also permits you to write your own compiler plug-ins.

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package org.checkerframework.dataflow.cfg.node;

import java.util.Collection;
import java.util.Collections;

import com.sun.source.tree.LiteralTree;
import com.sun.source.tree.Tree;

/**
 * A node for the null literal.
 *
 *  *   null
 * 
 *
 * @author Stefan Heule
 * @author Charlie Garrett
 *
 */
public class NullLiteralNode extends ValueLiteralNode {

    public NullLiteralNode(LiteralTree t) {
        super(t);
        assert t.getKind().equals(Tree.Kind.NULL_LITERAL);
    }

    @Override
    public Void getValue() {
        return (Void) tree.getValue();
    }

    @Override
    public  R accept(NodeVisitor visitor, P p) {
        return visitor.visitNullLiteral(this, p);
    }

    @Override
    public boolean equals(Object obj) {
        // test that obj is a NullLiteralNode
        if (obj == null || !(obj instanceof NullLiteralNode)) {
            return false;
        }
        // super method compares values
        return super.equals(obj);
    }

    @Override
    public Collection getOperands() {
        return Collections.emptyList();
    }
}