+/*
+ * BaseHandler.java
+ */
+package net.sf.openrocket.file.rocksim;
+
+import net.sf.openrocket.aerodynamics.WarningSet;
+import net.sf.openrocket.file.simplesax.ElementHandler;
+import net.sf.openrocket.material.Material;
+import net.sf.openrocket.rocketcomponent.RocketComponent;
+import org.xml.sax.SAXException;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.HashMap;
+
+/**
+ * An abstract base class that handles common parsing. All Rocksim component handlers are subclassed from here.
+ *
+ * @param <C> the specific RocketComponent subtype for which the concrete handler can create
+ */
+public abstract class BaseHandler<C extends RocketComponent> extends ElementHandler {
+
+ /**
+ * The overridden mass.
+ */
+ private Double mass = 0d;
+ /**
+ * The overridden Cg.
+ */
+ private Double cg = 0d;
+ /**
+ * The density of the material in the component.
+ */
+ private Double density = 0d;
+ /**
+ * The internal Rocksim density type.
+ */
+ private RocksimDensityType densityType = RocksimDensityType.ROCKSIM_BULK;
+
+ /**
+ * The material name.
+ */
+ private String materialName = "";
+
+ /**
+ * The SAX method called when the closing element tag is reached.
+ *
+ * @param element the element name.
+ * @param attributes attributes of the element.
+ * @param content the textual content of the element.
+ * @param warnings the warning set to store warnings in.
+ * @throws SAXException
+ */
+
+ @Override
+ public void closeElement(String element, HashMap<String, String> attributes, String content, WarningSet warnings)
+ throws SAXException {
+ final C component = getComponent();
+ try {
+ if ("Name".equals(element)) {
+ component.setName(content);
+ }
+ if ("KnownMass".equals(element)) {
+ mass = Math.max(0d, Double.parseDouble(content) / RocksimHandler.ROCKSIM_TO_OPENROCKET_MASS);
+ }
+ if ("Density".equals(element)) {
+ density = Math.max(0d, Double.parseDouble(content) );
+ }
+ if ("KnownCG".equals(element)) {
+ cg = Math.max(0d, Double.parseDouble(content) / RocksimHandler.ROCKSIM_TO_OPENROCKET_LENGTH);
+ }
+ if ("UseKnownCG".equals(element)) { //Rocksim sets UseKnownCG to true to control the override of both cg and mass
+ boolean override = "1".equals(content);
+ setOverride(component, override, mass, cg);
+ }
+ if ("DensityType".equals(element)) {
+ densityType = RocksimDensityType.fromCode(Integer.parseInt(content));
+ }
+ }
+ catch (NumberFormatException nfe) {
+ warnings.add("Could not convert " + element + " value of " + content + ". It is expected to be a number.");
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public void endHandler(String element, HashMap<String, String> attributes, String content, WarningSet warnings)
+ throws SAXException {
+ /* Because of the order of XML elements in Rocksim, not all information is known at the time it really needs
+ to be acted upon. So we keep temporary instance variables to be used here at the end of the parsing.
+ */
+ density = computeDensity(densityType, density);
+ RocketComponent component = getComponent();
+ updateComponentMaterial(component, materialName, getMaterialType(), density);
+ }
+
+ /**
+ * Compute the density. Rocksim does strange things with densities. For some streamer material it's in cubic,
+ * rather than square, units. In those cases it needs to be converted to an appropriate SURFACE material density.
+ * Some G10 fiberglass materials are in cubic units, other G10 fiberglass is in square units. And due to a
+ * Rocksim bug, some densities are 0 when they clearly should not be.
+ *
+ * This may be overridden for specific component density computations.
+ *
+ * @param type the rocksim density
+ * @param rawDensity the density as specified in the Rocksim design file
+ * @return a value in OpenRocket SURFACE density units
+ */
+ protected double computeDensity(RocksimDensityType type, double rawDensity) {
+ return rawDensity / type.asOpenRocket();
+ }
+
+ /**
+ * If the Rocksim component does not override the mass, then create a Material based upon the density defined
+ * for that component. This *should* result in a consistent representation of Cg between Rocksim and OpenRocket.
+ *
+ * @param component the component
+ * @param type the type of the material
+ * @param density the density in g/cm^3
+ * @param definedMaterial the material that is currently defined on the component; used only to get the name
+ * as it appears in Rocksim
+ */
+ public static void updateComponentMaterial(RocketComponent component, String definedMaterial, Material.Type type,
+ double density) {
+ if (definedMaterial != null) {
+ Material custom = createCustomMaterial(type, definedMaterial, density);
+ setMaterial(component, custom);
+ }
+ }
+
+ /**
+ * Override the mass and Cg of the component.
+ *
+ * @param component the component
+ * @param override true if any override should happen
+ * @param mass the override mass
+ * @param cg the override cg
+ */
+ public static void setOverride(RocketComponent component, boolean override, double mass, double cg) {
+ if (override) {
+ component.setCGOverridden(override);
+ component.setMassOverridden(override);
+ component.setOverrideSubcomponents(false); //Rocksim does not support this type of override
+ component.setOverrideMass(mass);
+ component.setOverrideCGX(cg);
+ }
+ }
+
+ /**
+ * Get the component this handler is working upon.
+ *
+ * @return a component
+ */
+ protected abstract C getComponent();
+
+ /**
+ * Get the required type of material for this component.
+ *
+ * @return the required material type
+ */
+ protected abstract Material.Type getMaterialType();
+
+ /**
+ * Some CG positions in Rocksim do not correspond to the CG position reference in OpenRocket.
+ *
+ * @param theCG the CG value to really use when overriding CG on the OpenRocket component
+ */
+ protected void setCG(double theCG) {
+ cg = theCG;
+ }
+
+ /**
+ * Set the material name as specified in the Rocksim design file.
+ *
+ * @param content the material name
+ */
+ protected void setMaterialName(String content) {
+ materialName = content;
+ }
+
+ /**
+ * Create a custom material based on the density.
+ *
+ * @param type the type of the material
+ * @param name the name of the component
+ * @param density the density in g/cm^3
+ *
+ * @return a Material instance
+ */
+ public static Material createCustomMaterial(Material.Type type, String name, double density) {
+ return Material.newMaterial(type, "RS: " + name, density, true);
+ }
+
+ /**
+ * Set the material onto an instance of RocketComponent. This is done because only some subtypes of RocketComponent
+ * have the setMaterial method. Unfortunately the supertype cannot be used.
+ *
+ * @param component the component who's material is to be set
+ * @param material the material to be set on the component (defined by getComponent())
+ */
+ private static void setMaterial(RocketComponent component, Material material) {
+ try {
+ final Method method = getMethod(component, "setMaterial", new Class[]{Material.class});
+ if (method != null) {
+ method.invoke(component, material);
+ }
+ }
+ catch (IllegalAccessException ignored) {
+ }
+ catch (InvocationTargetException ignored) {
+ }
+ }
+
+ /**
+ * Find a method by name and argument list.
+ *
+ * @param component the component who's material is to be seta
+ * @param name the method name
+ * @param args the class types of the parameters
+ *
+ * @return the Method instance, or null
+ */
+ private static Method getMethod(RocketComponent component, String name, Class[] args) {
+ Method method = null;
+ try {
+ method = component.getClass().getMethod(name, args);
+ }
+ catch (NoSuchMethodException ignored) {
+ }
+ return method;
+ }
+
+}