SimpleTextSerialiser.java

package org.dcache.services.info.serialisation;

import java.util.Map;

import org.dcache.services.info.base.BooleanStateValue;
import org.dcache.services.info.base.FloatingPointStateValue;
import org.dcache.services.info.base.IntegerStateValue;
import org.dcache.services.info.base.State;
import org.dcache.services.info.base.StateExhibitor;
import org.dcache.services.info.base.StatePath;
import org.dcache.services.info.base.StringStateValue;


/**
 * The SimpleTextSerialiser converts the dCache State tree into a simple String
 * representation.  This representation contains multiple lines, each containing
 * the path to the metric followed by a colon, then a space, the value, then
 * finally the metric type (in square brackets).
 * <p>
 * NB, instances of this Class are not thread-safe: the caller is responsible for
 * ensuring no concurrent calls to serialise().
 *
 * @see PrettyPrintTextSerialiser
 *
 * @author Paul Millar <paul.millar@desy.de>
 */
public class SimpleTextSerialiser extends SubtreeVisitor implements StateSerialiser
{
    public static final String NAME = "simple";

    private static final String LIST_TYPE = "List item";

    private StringBuilder _result = new StringBuilder();
    private StatePath _lastStateComponentPath;
    private StatePath _startPath;
    private StateExhibitor _exhibitor;

    public void setStateExhibitor(StateExhibitor exhibitor)
    {
        _exhibitor = exhibitor;
    }

    @Override
    public String serialise(StatePath start)
    {
        _result = new StringBuilder();
        _startPath = start;
        if (start != null) {
            setVisitScopeToSubtree(start);
        } else {
            setVisitScopeToEverything();
        }

        if (start != null) {
            _result.append(start.toString());
            _result.append(">\n");
        }

        _exhibitor.visitState(this);

        return _result.toString();
    }

    @Override
    public String serialise()
    {
        return serialise(null);
    }


    @Override
    public String getName()
    {
        return NAME;
    }

    @Override
    public void visitBoolean(StatePath path, BooleanStateValue value)
    {
        outputMetric(path, value.toString(), value.getTypeName());
        _lastStateComponentPath = path;
    }

    @Override
    public void visitFloatingPoint(StatePath path, FloatingPointStateValue value)
    {
        outputMetric(path, value.toString(), value.getTypeName());
        _lastStateComponentPath = path;
    }

    @Override
    public void visitInteger(StatePath path, IntegerStateValue value)
    {
        outputMetric(path, value.toString(), value.getTypeName());
        _lastStateComponentPath = path;
    }

    @Override
    public void visitString(StatePath path, StringStateValue value)
    {
        outputMetric(path, "\""+value+"\"", value.getTypeName());
        _lastStateComponentPath = path;
    }

    @Override
    public void visitCompositePreDescend(StatePath path, Map<String, String> metadata)
    {
        if (!isInsideScope(path)) {
            return;
        }

        _lastStateComponentPath = path;
    }

    @Override
    public void visitCompositePostDescend(StatePath path, Map<String, String> metadata)
    {
        if (!isInsideScope(path)) {
            return;
        }

        // If we just traversed a path without it containing any elements, treat it as a list.
        if (path != null && path.equals(_lastStateComponentPath) && !path.isSimplePath()) {
            String type = LIST_TYPE;

            if (metadata != null) {
                String className = metadata.get(State.METADATA_BRANCH_CLASS_KEY);
                if (className != null) {
                    type = className;
                }
            }
            outputMetric(path, "", type);
        }
    }

    /**
     * Output a single line, corresponding to a metric value.
     * @param path  The StatePath for this metric
     * @param metricValue the String representing this metric's current value.
     * @param metricType the type of metric.
     */
    private void outputMetric(StatePath path, String metricValue, String metricType)
    {
        if (_startPath != null) {
            _result.append("  ");
        }

        if (path != null) {
            _result.append(path.toString(_startPath));
        }

        _result.append(":  ");
        _result.append(metricValue);
        _result.append(" [");
        _result.append(metricType);
        _result.append("]\n");
    }
}