com.xeiam.xchange.rest.RestMethodMetadata.java Source code

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Here is the source code for com.xeiam.xchange.rest.RestMethodMetadata.java

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/**
 * Copyright (C) 2013 Matija Mazi
 * Copyright (C) 2013 Xeiam LLC http://xeiam.com
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is furnished to do
 * so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package com.xeiam.xchange.rest;

import java.io.IOException;
import java.io.Serializable;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import javax.ws.rs.Consumes;
import javax.ws.rs.FormParam;
import javax.ws.rs.HeaderParam;
import javax.ws.rs.PathParam;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.MediaType;

import com.fasterxml.jackson.databind.ObjectMapper;

/**
 * This holds name-value mapping for various types of params used in REST (QueryParam, PathParam, FormParam, HeaderParam).
 * 
 * @author Matija Mazi
 */
public class RestMethodMetadata implements Serializable {

    @SuppressWarnings("unchecked")
    private static final List<Class<? extends Annotation>> PARAM_ANNOTATION_CLASSES = Arrays
            .asList(QueryParam.class, PathParam.class, FormParam.class, HeaderParam.class);

    private final ObjectMapper objectMapper = new ObjectMapper();

    private final String contentType;
    private final Map<Class<? extends Annotation>, Params> paramsMap;
    private final List<Object> unannanotatedParams = new ArrayList<Object>();

    public RestMethodMetadata(Method method, Object[] args) {

        Consumes consumes = AnnotationUtils.getFromMethodOrClass(method, Consumes.class);
        this.contentType = consumes != null ? consumes.value()[0] : MediaType.APPLICATION_FORM_URLENCODED;

        paramsMap = new HashMap<Class<? extends Annotation>, Params>();
        for (Class<? extends Annotation> annotationClass : PARAM_ANNOTATION_CLASSES) {
            Params params = Params.of();
            params.setRestMethodMetadata(this);
            paramsMap.put(annotationClass, params);
        }

        Annotation[][] paramAnnotations = method.getParameterAnnotations();
        for (int i = 0; i < paramAnnotations.length; i++) {
            Annotation[] paramAnns = paramAnnotations[i];
            if (paramAnns.length == 0) {
                unannanotatedParams.add(args[i]);
            }
            for (Annotation paramAnn : paramAnns) {
                String paramName = getParamName(paramAnn);
                if (paramName != null) {
                    this.paramsMap.get(paramAnn.annotationType()).add(paramName, args[i]);
                }
            }
        }

        // Support using method method name as a parameter.
        for (Class<? extends Annotation> paramAnnotationClass : PARAM_ANNOTATION_CLASSES) {
            if (method.isAnnotationPresent(paramAnnotationClass)) {
                Annotation paramAnn = method.getAnnotation(paramAnnotationClass);
                String paramName = getParamName(paramAnn);
                this.paramsMap.get(paramAnnotationClass).add(paramName, method.getName());
            }
        }
    }

    // todo: this is needed only for testing
    public RestMethodMetadata(Map<Class<? extends Annotation>, Params> paramsMap, String contentType) {

        this.contentType = contentType;
        this.paramsMap = new LinkedHashMap<Class<? extends Annotation>, Params>(paramsMap);
        for (Params params : this.paramsMap.values()) {
            params.setRestMethodMetadata(this);
        }
    }

    static RestMethodMetadata createInstance(Method method, Object[] args) {

        return new RestMethodMetadata(method, args);
    }

    private static String getParamName(Annotation queryParam) {

        for (Class<? extends Annotation> annotationClass : PARAM_ANNOTATION_CLASSES) {
            String paramName = AnnotationUtils.getValueOrNull(annotationClass, queryParam);
            if (paramName != null) {
                return paramName;
            }
        }
        // This is not one of the annotations in PARAM_ANNOTATION_CLASSES.
        return null;
    }

    public String getPath(String methodPath) {

        return paramsMap.get(PathParam.class).applyToPath(methodPath);
    }

    public String getRequestBody() {

        if (MediaType.APPLICATION_FORM_URLENCODED.equals(contentType)) {
            return paramsMap.get(FormParam.class).asFormEncodedRequestBody();
        } else if (MediaType.APPLICATION_JSON.equals(contentType)) {
            if (!paramsMap.get(FormParam.class).isEmpty()) {
                throw new IllegalArgumentException(
                        "@FormParams are not allowed with " + MediaType.APPLICATION_JSON);
            } else if (unannanotatedParams.size() > 1) {
                throw new IllegalArgumentException(
                        "Can only have a single unnanotated parameter with " + MediaType.APPLICATION_JSON);
            }
            if (unannanotatedParams.size() == 0) {
                return null;
            }
            try {
                return objectMapper.writeValueAsString(unannanotatedParams.get(0));
            } catch (IOException e) {
                throw new RuntimeException("Error writing json, probably a bug.", e);
            }
        }
        throw new IllegalArgumentException("Unsupported media type: " + contentType);
    }

    public Map<String, String> getHttpHeaders() {

        return paramsMap.get(HeaderParam.class).asHttpHeaders();
    }

    public String getQueryString() {

        return paramsMap.get(QueryParam.class).asQueryString();
    }

    public String getContentType() {

        return contentType;
    }
}