001/*
002 * (C) Copyright 2013 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     dmetzler
018 */
019package org.nuxeo.ecm.automation.jaxrs.io;
020
021import java.io.IOException;
022import java.lang.annotation.Annotation;
023import java.lang.reflect.ParameterizedType;
024import java.lang.reflect.Type;
025import java.util.List;
026
027import javax.ws.rs.core.MediaType;
028
029import org.codehaus.jackson.JsonGenerator;
030import org.nuxeo.ecm.automation.core.util.Paginable;
031
032/**
033 * Abstract class that knows how to serialize List of nuxeo entities. The implementing classes should only implement
034 * {@link #getEntityType()} and {@link #writeItem(JsonGenerator, Object)}
035 *
036 * @since 5.7.3
037 */
038public abstract class EntityListWriter<T> extends EntityWriter<List<T>> {
039
040    /**
041     * Returns the entity-type value of the list (ie: users, groups....)
042     */
043    protected abstract String getEntityType();
044
045    /**
046     * Writes the item in a JsonGenerator.
047     */
048    protected abstract void writeItem(JsonGenerator jg, T item) throws IOException;
049
050    @Override
051    public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
052        if (!List.class.isAssignableFrom(type)) {
053            return false;
054        }
055
056        // Verify the generic argument type
057        if (genericType instanceof ParameterizedType) {
058            ParameterizedType paramType = (ParameterizedType) genericType;
059            Type actualTypeArguments = paramType.getActualTypeArguments()[0];
060            if (type == null) {
061                throw new RuntimeException("Invalid class parameter type.");
062            }
063            return ((Class<?>) actualTypeArguments).isAssignableFrom(getItemClass());
064
065        }
066        return false;
067    }
068
069    private Class<?> getItemClass() {
070        return (Class<?>) ((ParameterizedType) getClass().getGenericSuperclass()).getActualTypeArguments()[0];
071    }
072
073    @Override
074    protected void writeEntityBody(JsonGenerator jg, List<T> list) throws IOException {
075        writePaginableHeader(jg, list);
076        writeHeader(jg, list);
077        jg.writeArrayFieldStart("entries");
078        for (T item : list) {
079            writeItem(jg, item);
080        }
081        jg.writeEndArray();
082    }
083
084    protected void writePaginableHeader(JsonGenerator jg, List<T> list) throws IOException {
085        if (list instanceof Paginable) {
086            @SuppressWarnings("rawtypes")
087            Paginable paginable = (Paginable) list;
088            jg.writeBooleanField("isPaginable", true);
089            jg.writeNumberField("resultsCount", paginable.getResultsCount());
090            jg.writeNumberField("pageSize", paginable.getPageSize());
091            jg.writeNumberField("maxPageSize", paginable.getMaxPageSize());
092            jg.writeNumberField("currentPageSize", paginable.getCurrentPageSize());
093            jg.writeNumberField("currentPageIndex", paginable.getCurrentPageIndex());
094            jg.writeNumberField("numberOfPages", paginable.getNumberOfPages());
095            jg.writeBooleanField("isPreviousPageAvailable", paginable.isPreviousPageAvailable());
096            jg.writeBooleanField("isNextPageAvailable", paginable.isNextPageAvailable());
097            jg.writeBooleanField("isLastPageAvailable", paginable.isLastPageAvailable());
098            jg.writeBooleanField("isSortable", paginable.isSortable());
099            jg.writeBooleanField("hasError", paginable.hasError());
100            jg.writeStringField("errorMessage", paginable.getErrorMessage());
101            if (paginable.hasAggregateSupport() && paginable.getAggregates() != null
102                    && !paginable.getAggregates().isEmpty()) {
103                jg.writeObjectField("aggregations", paginable.getAggregates());
104            }
105        }
106    }
107
108    /**
109     * Override this method to write into list header
110     */
111    protected void writeHeader(JsonGenerator jg, List<T> list) throws IOException {
112    }
113
114}