org.yamcs.templating.IfStatement Maven / Gradle / Ivy
package org.yamcs.templating;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.Map;
public class IfStatement implements Statement {
private String identifier;
private TemplateBody ifBody;
private LinkedHashMap elifConditions;
private TemplateBody elseBody;
public IfStatement(String identifier, TemplateBody ifBody, LinkedHashMap elifConditions,
TemplateBody elseBody) {
this.identifier = identifier;
this.ifBody = ifBody;
this.elifConditions = elifConditions;
this.elseBody = elseBody;
}
@Override
public void render(StringBuilder buf, Map vars, Map filters) {
var value = getValue(identifier, vars);
if (isTruthy(value)) {
buf.append(ifBody.render(vars, filters));
return;
}
for (var entry : elifConditions.entrySet()) {
value = getValue(entry.getKey(), vars);
if (isTruthy(value)) {
buf.append(entry.getValue().render(vars, filters));
return;
}
}
if (elseBody != null) {
buf.append(elseBody.render(vars, filters));
}
}
private Object getValue(String name, Map args) {
return getValue(name, args, "");
}
@SuppressWarnings("unchecked")
private Object getValue(String name, Map args, String nameContext) {
int dotIndex = name.indexOf('.');
if (dotIndex == -1) {
return args.get(name);
} else {
String parentName = name.substring(0, dotIndex);
Object parentValue = args.get(parentName);
if (parentValue == null) {
throw new IllegalArgumentException(String.format(
"Variable '%s%s' is not set", nameContext, parentName));
}
if (!(parentValue instanceof Map)) {
throw new IllegalArgumentException(String.format(
"Variable '%s%s' is not a map", nameContext, parentName));
}
Map parentArgs = (Map) parentValue;
return getValue(name.substring(dotIndex + 1), parentArgs);
}
}
private boolean isTruthy(Object value) {
return !isFalsy(value);
}
private boolean isFalsy(Object value) {
if (value == null) {
return true;
}
if (value instanceof Boolean) {
return (Boolean) value;
}
if (value instanceof String) {
return ((String) value).trim().isEmpty();
}
if (value instanceof Collection) {
return ((Collection) value).isEmpty();
}
if (value.getClass().isArray()) {
return ((Object[]) value).length == 0;
}
return false;
}
}