flabbergast.JavaSourceReference Maven / Gradle / Ivy

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package flabbergast;

import java.io.IOException;
import java.io.Writer;
import java.util.Set;

/**
 * A stack element that captures a Java context.
 */
public class JavaSourceReference extends SourceReference {
    private static final int SKIP = 2;
    private final String task_master_name = TaskMaster.class.getName();
    private final StackTraceElement[] trace;

    public JavaSourceReference() {
        StackTraceElement[] stack_trace = Thread.currentThread()
                                          .getStackTrace();
        int end;
        for (end = SKIP; end < stack_trace.length; end++) {
            if (stack_trace[end].getClassName().equals(task_master_name)) {
                break;
            }
        }

        trace = new StackTraceElement[end - SKIP];
        for (int it = 0; it < trace.length; it++) {
            trace[it] = stack_trace[it + SKIP];
        }
    }

    @Override
    public void write(Writer writer, String prefix, Set seen)
    throws IOException {
        boolean before = seen.contains(this);
        seen.add(this);

        int length = before ? 1 : trace.length;

        for (int it = 0; it < length; it++) {
            writer.write(prefix);
            writer.write(it < trace.length - 1 ? "├ " : "└ ");
            writer.write(trace[it].toString());
            if (before) {
                writer.write(" (previously mentioned)\n");
                writer.write(prefix);
                writer.write("┊");
            }
            writer.write("\n");
        }
    }
}