juneau-rest/juneau-rest-server/src/main/java/org/apache/juneau/rest/args/HeaderArg.java

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package org.apache.juneau.rest.args;

import static org.apache.juneau.internal.ClassUtils.*;
import static org.apache.juneau.internal.StringUtils.*;

import java.util.*;

import org.apache.juneau.*;
import org.apache.juneau.collections.*;
import org.apache.juneau.http.annotation.*;
import org.apache.juneau.httppart.*;
import org.apache.juneau.internal.*;
import org.apache.juneau.reflect.*;
import org.apache.juneau.rest.*;
import org.apache.juneau.rest.annotation.*;

/**
 * Resolves method parameters and parameter types annotated with {@link Header} on {@link RestOp}-annotated Java methods.
 *
 * <p>
 * The parameter value is resolved using <c><jv>call</jv>.{@link RestCall#getRestRequest() getRestRequest}().{@link RestRequest#getHeaders() getHeaders}()./c>
 * with a {@link HttpPartSchema schema} derived from the {@link Header} annotation.
 *
 * <p>
 * If the {@link Header#multi()} flag is set, then the data type can be a {@link Collection} or array.
 */
public class HeaderArg implements RestOperationArg {
	private final HttpPartParser partParser;
	private final HttpPartSchema schema;
	private final boolean multi;
	private final String name;
	private final ClassInfo type;

	/**
	 * Static creator.
	 *
	 * @param paramInfo The Java method parameter being resolved.
	 * @param cp The configuration properties of the {@link RestContext}.
	 * @return A new {@link HeaderArg}, or <jk>null</jk> if the parameter is not annotated with {@link Header}.
	 */
	public static HeaderArg create(ParamInfo paramInfo, ContextProperties cp) {
		if (paramInfo.hasAnnotation(Header.class) || paramInfo.getParameterType().hasAnnotation(Header.class))
			return new HeaderArg(paramInfo, cp);
		return null;
	}

	/**
	 * Constructor.
	 *
	 * @param paramInfo The Java method parameter being resolved.
	 * @param cp The configuration properties of the {@link RestContext}.
	 */
	protected HeaderArg(ParamInfo paramInfo, ContextProperties cp) {
		this.name = getName(paramInfo);
		this.type = paramInfo.getParameterType();
		this.schema = HttpPartSchema.create(Header.class, paramInfo);
		this.partParser = castOrCreate(HttpPartParser.class, schema.getParser(), true, cp);
		this.multi = getMulti(paramInfo);

		if (multi && ! type.isCollectionOrArray())
			throw new ArgException(paramInfo, "Use of multipart flag on @Header parameter that is not an array or Collection");
	}

	private String getName(ParamInfo paramInfo) {
		String n = null;
		for (Header h : paramInfo.getAnnotations(Header.class))
			n = firstNonEmpty(h.name(), h.n(), h.value(), n);
		for (Header h : paramInfo.getParameterType().getAnnotations(Header.class))
			n = firstNonEmpty(h.name(), h.n(), h.value(), n);
		if (n == null)
			throw new ArgException(paramInfo, "@Header used without name or value");
		return n;
	}

	private boolean getMulti(ParamInfo paramInfo) {
		for (Header h : paramInfo.getAnnotations(Header.class))
			if (h.multi())
				return true;
		for (Header h : paramInfo.getParameterType().getAnnotations(Header.class))
			if (h.multi())
				return true;
		return false;
	}

	@SuppressWarnings({ "rawtypes", "unchecked" })
	@Override /* RestOperationArg */
	public Object resolve(RestCall call) throws Exception {
		RestRequest req = call.getRestRequest();
		HttpPartParserSession ps = partParser == null ? req.getPartParserSession() : partParser.createPartSession(req.getParserSessionArgs());
		RequestHeaders rh = call.getRestRequest().getHeaders();
		BeanSession bs = call.getRestRequest().getBeanSession();
		ClassMeta<?> cm = bs.getClassMeta(type.innerType());

		if (multi) {
			Collection c = cm.isArray() ? new ArrayList<>() : (Collection)(cm.canCreateNewInstance() ? cm.newInstance() : new OList());
			rh.getAll(name).stream().map(x -> x.parser(ps).schema(schema).asType(cm.getElementType()).orElse(null)).forEach(x -> c.add(x));
			return cm.isArray() ? ArrayUtils.toArray(c, cm.getElementType().getInnerClass()) : c;
		}

		if (cm.isMapOrBean() && isOneOf(name, "*", "")) {
			OMap m = new OMap();
			for (RequestHeader e : rh.getAll())
				m.put(e.getName(), e.parser(ps).schema(schema == null ? null : schema.getProperty(e.getName())).asType(cm.getValueType()).orElse(null));
			return req.getBeanSession().convertToType(m, cm);
		}

		return rh.getLast(name).parser(ps).schema(schema).asType(type.innerType()).orElse(null);
	}
}