Java tutorial
/** * Copyright (C) 2010 Orbeon, Inc. * * This program is free software; you can redistribute it and/or modify it under the terms of the * GNU Lesser General Public License as published by the Free Software Foundation; either version * 2.1 of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. * See the GNU Lesser General Public License for more details. * * The full text of the license is available at http://www.gnu.org/copyleft/lesser.html */ package org.orbeon.oxf.processor.pipeline.choose; import org.apache.commons.collections.CollectionUtils; import org.dom4j.Element; import org.orbeon.oxf.common.ValidationException; import org.orbeon.oxf.processor.*; import org.orbeon.oxf.processor.pipeline.PipelineProcessor; import org.orbeon.oxf.processor.pipeline.ast.*; import org.orbeon.oxf.xml.NamespaceMapping; import org.orbeon.oxf.xml.XMLConstants; import org.orbeon.oxf.xml.dom4j.Dom4jUtils; import org.orbeon.oxf.xml.dom4j.LocationData; import java.util.*; /** * <p><b>Usage</b> * <p>This processor is not intended to be used by itelf. Instead, it is used by * the PipelineProcessor (so we can keep the PipelineProcessor simpler and * see the "choose" functionnality as if it was just an other processor). * <p/> * <p><b>Lifecycle</b> * <ol> * <li>createInput("config") is called. * <li>createInstance() is called. * <li>At this point the config (<p:choose> block) is read and we determine * for each branch all the inputs (<input ref="..."> with no corresponding * <output id="...">) and all the outputs (<output id="..."> with no * <input ref="...">). * <li>We ensure that the collection of outputs is exactly the * same for each branch. * <li>We create a pipeline config with the text of each branch, adding the * appropriate <p:param> and appropriate ref="..." attribute to reference * those parameters. * <li>The collections of pipelines can be cached. * <li>We read the input referenced in the <p:choose> and choose which pipeline * has to be executed. * <li>We connect the selected pipeline with the input of this processor. * <li>We start every all the outputs of the pipeline, store the result in a * SAXStore and play it back when the read of the corresponding output * is called. * </ol> */ public class AbstractChooseProcessor extends ProcessorImpl implements AbstractProcessor { public static final String CHOOSE_DATA_INPUT = "$data"; private ASTChoose chooseAST; private Object validity; public AbstractChooseProcessor(ASTChoose chooseAST, Object validity) { this.chooseAST = chooseAST; this.validity = validity; setLocationData(chooseAST.getLocationData()); } public Processor createInstance() { // We store here the "refs with no id" and "ids with no ref" for each branch. // Those are list of collections (one collection for each branch). final List refsWithNoId = new ArrayList(); final List idsWithNoRef = new ArrayList(); final List paramRefs = new ArrayList(); for (Iterator astIterator = chooseAST.getWhen().iterator(); astIterator.hasNext();) { // Get info about id used in this branch final ASTWhen when = (ASTWhen) astIterator.next(); IdInfo idInfo = when.getIdInfo(); paramRefs.add(idInfo.getOutputRefs()); // Determine all <p:input ref="..."> with no <p:output id="...">. // Those are the inputs of this processor. final Set branchRefsWithNoId = new HashSet(idInfo.getInputRefs()); branchRefsWithNoId.removeAll(idInfo.getOutputIds()); refsWithNoId.add(branchRefsWithNoId); // Determine all <p:output id="..."> with no <p:input ref="...">. // Those are the outputs of this processor. final Set branchIdsWithNoRef = new HashSet(idInfo.getOutputIds()); branchIdsWithNoRef.removeAll(idInfo.getInputRefs()); idsWithNoRef.add(branchIdsWithNoRef); } // Make sure that the "ids with no ref" are the same for each branch if (idsWithNoRef.size() > 1) { final Collection firstBranchIdsWithNoRef = (Collection) idsWithNoRef.get(0); int branchId = 0; for (Iterator i = idsWithNoRef.iterator(); i.hasNext();) { branchId++; final Collection branchIdsWithNoRef = (Collection) i.next(); if (branchIdsWithNoRef != firstBranchIdsWithNoRef && !CollectionUtils.isEqualCollection(branchIdsWithNoRef, firstBranchIdsWithNoRef)) throw new ValidationException("ASTChoose branch number " + branchId + " does not declare the same ids " + branchIdsWithNoRef.toString() + " as the previous branches " + firstBranchIdsWithNoRef.toString(), getLocationData()); } } // Make sure that the "param ref" are the same for each branch if (paramRefs.size() > 1) { final Collection firstBranchParamRefs = (Collection) paramRefs.get(0); int branchId = 0; for (Iterator i = paramRefs.iterator(); i.hasNext();) { branchId++; final Collection branchParamRefs = (Collection) i.next(); if (branchParamRefs != firstBranchParamRefs && !CollectionUtils.isEqualCollection(branchParamRefs, firstBranchParamRefs)) throw new ValidationException("ASTChoose branch number " + branchId + " does not declare the same refs " + branchParamRefs.toString() + " as the previous branches " + firstBranchParamRefs.toString(), getLocationData()); } } // Compute the union of "refs with no id" for all the branches final Set allRefsWithNoId = new HashSet(); for (Iterator i = refsWithNoId.iterator(); i.hasNext();) allRefsWithNoId.addAll((Set) i.next()); // Create the list of inputs based on allRefsWithNoId final List astParams = new ArrayList(); for (int i = 0; i < 2; i++) { final Set parameters; if (i == 0) { parameters = allRefsWithNoId; } else { parameters = new HashSet(); parameters.addAll((Set) idsWithNoRef.get(0)); parameters.addAll((Set) paramRefs.get(0)); } for (Iterator j = parameters.iterator(); j.hasNext();) { final String paramName = (String) j.next(); ASTParam astParam = new ASTParam(); astParam.setType(i == 0 ? ASTParam.INPUT : ASTParam.OUTPUT); astParam.setName(paramName); astParams.add(astParam); } } // For each branch, create a new pipeline processor final List<Processor> branchProcessors = new ArrayList(); final List branchConditions = new ArrayList(); final List<NamespaceMapping> branchNamespaces = new ArrayList<NamespaceMapping>(); for (Iterator astIterator = chooseAST.getWhen().iterator(); astIterator.hasNext();) { final ASTWhen astWhen = (ASTWhen) astIterator.next(); // Save condition branchConditions.add(astWhen.getTest()); // Get namespaces declared at this point in the pipeline if (astWhen.getNode() != null && astWhen.getNamespaces().mapping.size() != 0) { throw new ValidationException("ASTWhen cannot have both a node and namespaces defined", astWhen.getLocationData()); } branchNamespaces.add(astWhen.getNode() != null ? new NamespaceMapping(Dom4jUtils.getNamespaceContextNoDefault((Element) astWhen.getNode())) : astWhen.getNamespaces()); // Add an identity processor to connect the output of the branch to // the <param type="output"> of the pipeline final Set idsToConvert = (Set) idsWithNoRef.get(0); for (Iterator i = idsToConvert.iterator(); i.hasNext();) { final String id = (String) i.next(); final ASTProcessorCall identityConnector = new ASTProcessorCall( XMLConstants.IDENTITY_PROCESSOR_QNAME); { identityConnector.addInput(new ASTInput("data", new ASTHrefId(new ASTOutput(null, id)))); final ASTParam outParam = new ASTParam(ASTParam.OUTPUT, id); final LocationData locDat = Dom4jUtils.getLocationData(); final ASTOutput astOut = new ASTOutput("data", outParam); astOut.setLocationData(locDat); identityConnector.addOutput(astOut); } astWhen.addStatement(identityConnector); } final ASTPipeline astPipeline = new ASTPipeline(); astPipeline.setValidity(validity); astPipeline.getParams().addAll(astParams); astPipeline.getStatements().addAll(astWhen.getStatements()); astPipeline.setNode(astWhen.getNode()); final Processor pipelineProcessor = new PipelineProcessor(astPipeline); if (getId() != null) pipelineProcessor.setId(getId() + "-branch" + branchProcessors.size()); branchProcessors.add(pipelineProcessor); } return new ConcreteChooseProcessor(getId(), getLocationData(), branchConditions, branchNamespaces, branchProcessors, allRefsWithNoId, (Set) idsWithNoRef.get(0), (Set) paramRefs.get(0)); } }