Java tutorial
/* * Copyright 2007 Yusuke Yamamoto * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package twitter4j; import java.util.ArrayList; import java.util.List; /** * Controls pagination.<br> * It is possible to use the same Paging instance in a multi-threaded * context only if the instance is treated immutably.<br> * But basically instance of this class is NOT thread safe. * A client should instantiate Paging class per thread.<br> * * @author Yusuke Yamamoto - yusuke at mac.com */ public final class Paging implements java.io.Serializable { private static final long serialVersionUID = -7226113618341047983L; private int page = -1; private int count = -1; private long sinceId = -1; private long maxId = -1; // since only static final char[] S = new char[] { 's' }; // since, max_id, count, page static final char[] SMCP = new char[] { 's', 'm', 'c', 'p' }; static final String COUNT = "count"; // somewhat GET list statuses requires "per_page" instead of "count" // @see <a href="https://dev.twitter.com/docs/api/1.1/get/:user/lists/:id/statuses">GET :user/lists/:id/statuses | Twitter Developers</a> static final String PER_PAGE = "per_page"; /*package*/ List<HttpParameter> asPostParameterList() { return asPostParameterList(SMCP, COUNT); } private static final HttpParameter[] NULL_PARAMETER_ARRAY = new HttpParameter[0]; /*package*/ HttpParameter[] asPostParameterArray() { List<HttpParameter> list = asPostParameterList(SMCP, COUNT); if (list.size() == 0) { return NULL_PARAMETER_ARRAY; } return list.toArray(new HttpParameter[list.size()]); } /*package*/ List<HttpParameter> asPostParameterList(char[] supportedParams) { return asPostParameterList(supportedParams, COUNT); } private static final List<HttpParameter> NULL_PARAMETER_LIST = new ArrayList<HttpParameter>(0); /** * Converts the pagination parameters into a List of PostParameter.<br> * This method also Validates the preset parameters, and throws * IllegalStateException if any unsupported parameter is set. * * @param supportedParams char array representation of supported parameters * @param perPageParamName name used for per-page parameter. getUserListStatuses() requires "per_page" instead of "count". * @return list of PostParameter */ /*package*/ List<HttpParameter> asPostParameterList(char[] supportedParams, String perPageParamName) { java.util.List<HttpParameter> pagingParams = new ArrayList<HttpParameter>(supportedParams.length); addPostParameter(supportedParams, 's', pagingParams, "since_id", getSinceId()); addPostParameter(supportedParams, 'm', pagingParams, "max_id", getMaxId()); addPostParameter(supportedParams, 'c', pagingParams, perPageParamName, getCount()); addPostParameter(supportedParams, 'p', pagingParams, "page", getPage()); if (pagingParams.size() == 0) { return NULL_PARAMETER_LIST; } else { return pagingParams; } } /** * Converts the pagination parameters into a List of PostParameter.<br> * This method also Validates the preset parameters, and throws * IllegalStateException if any unsupported parameter is set. * * @param supportedParams char array representation of supported parameters * @param perPageParamName name used for per-page parameter. getUserListStatuses() requires "per_page" instead of "count". * @return list of PostParameter */ /*package*/ HttpParameter[] asPostParameterArray(char[] supportedParams, String perPageParamName) { java.util.List<HttpParameter> pagingParams = new ArrayList<HttpParameter>(supportedParams.length); addPostParameter(supportedParams, 's', pagingParams, "since_id", getSinceId()); addPostParameter(supportedParams, 'm', pagingParams, "max_id", getMaxId()); addPostParameter(supportedParams, 'c', pagingParams, perPageParamName, getCount()); addPostParameter(supportedParams, 'p', pagingParams, "page", getPage()); if (pagingParams.size() == 0) { return NULL_PARAMETER_ARRAY; } else { return pagingParams.toArray(new HttpParameter[pagingParams.size()]); } } private void addPostParameter(char[] supportedParams, char paramKey, List<HttpParameter> pagingParams, String paramName, long paramValue) { boolean supported = false; for (char supportedParam : supportedParams) { if (supportedParam == paramKey) { supported = true; break; } } if (!supported && -1 != paramValue) { throw new IllegalStateException( "Paging parameter [" + paramName + "] is not supported with this operation."); } if (-1 != paramValue) { pagingParams.add(new HttpParameter(paramName, String.valueOf(paramValue))); } } public Paging() { } public Paging(int page) { setPage(page); } public Paging(long sinceId) { setSinceId(sinceId); } public Paging(int page, int count) { this(page); setCount(count); } public Paging(int page, long sinceId) { this(page); setSinceId(sinceId); } public Paging(int page, int count, long sinceId) { this(page, count); setSinceId(sinceId); } public Paging(int page, int count, long sinceId, long maxId) { this(page, count, sinceId); setMaxId(maxId); } public int getPage() { return page; } public void setPage(int page) { if (page < 1) { throw new IllegalArgumentException("page should be positive integer. passed:" + page); } this.page = page; } public int getCount() { return count; } public void setCount(int count) { if (count < 1) { throw new IllegalArgumentException("count should be positive integer. passed:" + count); } this.count = count; } public Paging count(int count) { setCount(count); return this; } public long getSinceId() { return sinceId; } public void setSinceId(long sinceId) { if (sinceId < 1) { throw new IllegalArgumentException("since_id should be positive integer. passed:" + sinceId); } this.sinceId = sinceId; } public Paging sinceId(long sinceId) { setSinceId(sinceId); return this; } public long getMaxId() { return maxId; } public void setMaxId(long maxId) { if (maxId < 1) { throw new IllegalArgumentException("max_id should be positive integer. passed:" + maxId); } this.maxId = maxId; } public Paging maxId(long maxId) { setMaxId(maxId); return this; } @Override public boolean equals(Object o) { if (this == o) return true; if (!(o instanceof Paging)) return false; Paging paging = (Paging) o; if (count != paging.count) return false; if (maxId != paging.maxId) return false; if (page != paging.page) return false; if (sinceId != paging.sinceId) return false; return true; } @Override public int hashCode() { int result = page; result = 31 * result + count; result = 31 * result + (int) (sinceId ^ (sinceId >>> 32)); result = 31 * result + (int) (maxId ^ (maxId >>> 32)); return result; } @Override public String toString() { return "Paging{" + "page=" + page + ", count=" + count + ", sinceId=" + sinceId + ", maxId=" + maxId + '}'; } }