Dedup.java

	public UnsignedLong incrementProperty(final UnsignedLong id, final String propKey, final UnsignedLong incrementAmount) {
		return changePropValue(id, propKey, oldProp -> oldProp.plus(incrementAmount));
	}

	public UnsignedLong decrementProperty(final UnsignedLong id, final String propKey, final UnsignedLong decrementAmount) {
		return changePropValue(id, propKey, oldProp -> oldProp.minus(decrementAmount));
	}

	public UnsignedLong getProperty(final UnsignedLong id, final String propKey) {
		return changePropValue(id, propKey, Function.identity());
	}

	public UnsignedLong setProperty(final UnsignedLong id, final String propKey, final UnsignedLong newValue) {
		return changePropValue(id, propKey, oldProp -> newValue);
	}

	private UnsignedLong changePropValue(final UnsignedLong id, final String propKey, final Function<UnsignedLong, UnsignedLong> updater) {
		try (final Transaction tx = namespaces.db().beginTx()) {
			final BushNode nsNode = namespaces.getNodeById(id.longValue());
			final UnsignedLong propValue = updater.apply(UnsignedLong.valueOf(nsNode.<Long>getProperty(propKey).orElse(0l)));
			if (!updater.equals(Function.identity())) {
				nsNode.setProperty(propKey, propValue);
			}
			tx.success();
			return propValue;
		}
	}