waveform record not supported?

[Matt-labor]

I got some waveform pv records. When I use Monitor, only one value is returned and the displayed Type is DBR_DOUBLE rather than DBR_WAVEFORM_DOUBLE. Is that because waveform record not supported by this project?

[slominskir]

Correct: epics2web generally does not support arrays. The only exception is byte[], which SNS contributed a code patch (#9) for that provides for long strings. See:

epics2web/src/main/java/org/jlab/epics2web/epics/ChannelManager.java

Lines 72 to 129 in 1999429

	public static String getDbrValueAsString(DBR dbr) {
	String strValue = null;
	if(dbr == null){
	strValue = "";
	} else if (dbr.isDOUBLE()) {
	double value = ((gov.aps.jca.dbr.DOUBLE) dbr).getDoubleValue()[0];
	if (Double.isFinite(value)) {
	strValue = String.valueOf(value);
	} else if (Double.isNaN(value)) {
	strValue = "NaN";
	} else {
	strValue = "Infinity";
	}
	} else if (dbr.isFLOAT()) {
	float value = ((gov.aps.jca.dbr.FLOAT) dbr).getFloatValue()[0];
	if (Float.isFinite(value)) {
	strValue = String.valueOf(value);
	} else if (Float.isNaN(value)) {
	strValue = "NaN";
	} else {
	strValue = "Infinity";
	}
	} else if (dbr.isINT()) {
	int value = ((gov.aps.jca.dbr.INT) dbr).getIntValue()[0];
	strValue = String.valueOf(value);
	} else if (dbr.isSHORT()) {
	short value = ((gov.aps.jca.dbr.SHORT) dbr).getShortValue()[0];
	strValue = String.valueOf(value);
	} else if (dbr.isENUM()) {
	short value = ((gov.aps.jca.dbr.ENUM) dbr).getEnumValue()[0];
	strValue = String.valueOf(value);
	} else if (dbr.isBYTE()) {
	byte[] value = ((gov.aps.jca.dbr.BYTE) dbr).getByteValue();
	int len = value.length;
	if (len > 1) {
	// epics2web generally doesn't handle arrays,
	// but for BYTE[] assume that data is really "long string".
	// Text ends at first '\0' or end of array
	for (int i=0; i<len; ++i)
	if (value[i] == 0) {
	len = i;
	break;
	}
	try {
	strValue = new String(value, 0, len, "UTF-8");
	} catch(UnsupportedEncodingException e) {
	throw new RuntimeException("JVM doesn't support UTF-8!");
	}
	}
	else
	strValue = String.valueOf(value[0]);
	} else {
	String value = ((gov.aps.jca.dbr.STRING) dbr).getStringValue()[0];
	strValue = value;
	}
	return strValue;
	}

Feel free to contribute a PR. Array data probably needs to be used sparingly / carefully to avoid performance issues though. JSON (String) format probably isn't a good choice for streaming large arrays. Therefore if large arrays are the goal then a solution would ideally also need to consider #1.