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.nuxeo.ecm.automation.core.util.Paginable;
030
031import com.fasterxml.jackson.core.JsonGenerator;
032
033/**
034 * Abstract class that knows how to serialize List of nuxeo entities. The implementing classes should only implement
035 * {@link #getEntityType()} and {@link #writeItem(JsonGenerator, Object)}
036 *
037 * @since 5.7.3
038 */
039public abstract class EntityListWriter<T> extends EntityWriter<List<T>> {
040
041    /**
042     * Returns the entity-type value of the list (ie: users, groups....)
043     */
044    protected abstract String getEntityType();
045
046    /**
047     * Writes the item in a JsonGenerator.
048     */
049    protected abstract void writeItem(JsonGenerator jg, T item) throws IOException;
050
051    @Override
052    public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
053        if (!List.class.isAssignableFrom(type)) {
054            return false;
055        }
056
057        // Verify the generic argument type
058        if (genericType instanceof ParameterizedType) {
059            ParameterizedType paramType = (ParameterizedType) genericType;
060            Type actualTypeArguments = paramType.getActualTypeArguments()[0];
061            if (type == null) {
062                throw new RuntimeException("Invalid class parameter type.");
063            }
064            return ((Class<?>) actualTypeArguments).isAssignableFrom(getItemClass());
065
066        }
067        return false;
068    }
069
070    private Class<?> getItemClass() {
071        return (Class<?>) ((ParameterizedType) getClass().getGenericSuperclass()).getActualTypeArguments()[0];
072    }
073
074    @Override
075    protected void writeEntityBody(JsonGenerator jg, List<T> list) throws IOException {
076        writePaginableHeader(jg, list);
077        writeHeader(jg, list);
078        jg.writeArrayFieldStart("entries");
079        for (T item : list) {
080            writeItem(jg, item);
081        }
082        jg.writeEndArray();
083    }
084
085    protected void writePaginableHeader(JsonGenerator jg, List<T> list) throws IOException {
086        if (list instanceof Paginable) {
087            @SuppressWarnings("rawtypes")
088            Paginable paginable = (Paginable) list;
089            jg.writeBooleanField("isPaginable", true);
090            jg.writeNumberField("resultsCount", paginable.getResultsCount());
091            jg.writeNumberField("pageSize", paginable.getPageSize());
092            jg.writeNumberField("maxPageSize", paginable.getMaxPageSize());
093            jg.writeNumberField("currentPageSize", paginable.getCurrentPageSize());
094            jg.writeNumberField("currentPageIndex", paginable.getCurrentPageIndex());
095            jg.writeNumberField("numberOfPages", paginable.getNumberOfPages());
096            jg.writeBooleanField("isPreviousPageAvailable", paginable.isPreviousPageAvailable());
097            jg.writeBooleanField("isNextPageAvailable", paginable.isNextPageAvailable());
098            jg.writeBooleanField("isLastPageAvailable", paginable.isLastPageAvailable());
099            jg.writeBooleanField("isSortable", paginable.isSortable());
100            jg.writeBooleanField("hasError", paginable.hasError());
101            jg.writeStringField("errorMessage", paginable.getErrorMessage());
102            if (paginable.hasAggregateSupport() && paginable.getAggregates() != null
103                    && !paginable.getAggregates().isEmpty()) {
104                jg.writeObjectField("aggregations", paginable.getAggregates());
105            }
106        }
107    }
108
109    /**
110     * Override this method to write into list header
111     */
112    protected void writeHeader(JsonGenerator jg, List<T> list) throws IOException {
113    }
114
115}