Java tutorial
/** * Copyright 2011-2018 PrimeFaces Extensions * * 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 org.primefaces.extensions.converter; import java.io.Serializable; import java.lang.reflect.Array; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import javax.el.ValueExpression; import javax.faces.application.FacesMessage; import javax.faces.component.UIComponent; import javax.faces.context.FacesContext; import javax.faces.convert.Converter; import javax.faces.convert.ConverterException; import javax.faces.convert.FacesConverter; import org.apache.commons.lang3.StringUtils; import org.primefaces.extensions.util.json.GsonConverter; import org.primefaces.extensions.util.json.ParameterizedTypeImpl; import org.primefaces.util.Constants; /** * {@link Converter} which converts a JSON string to an object an vice-versa. * * @author Thomas Andraschko / last modified by $Author$ * @version $Revision$ * @since 0.2 */ @FacesConverter(value = "org.primefaces.extensions.converter.JsonConverter") public class JsonConverter implements Converter, Serializable { private static final long serialVersionUID = 20121214L; private static final Map<String, Class<?>> PRIMITIVE_CLASSES = new HashMap<String, Class<?>>(); private static final Map<String, Class<?>> PRIMITIVE_ARRAY_CLASSES = new HashMap<String, Class<?>>(); static { PRIMITIVE_CLASSES.put("boolean", boolean.class); PRIMITIVE_CLASSES.put("byte", byte.class); PRIMITIVE_CLASSES.put("short", short.class); PRIMITIVE_CLASSES.put("char", char.class); PRIMITIVE_CLASSES.put("int", int.class); PRIMITIVE_CLASSES.put("long", long.class); PRIMITIVE_CLASSES.put("float", float.class); PRIMITIVE_CLASSES.put("double", double.class); PRIMITIVE_ARRAY_CLASSES.put("boolean[]", boolean[].class); PRIMITIVE_ARRAY_CLASSES.put("byte[]", byte[].class); PRIMITIVE_ARRAY_CLASSES.put("short[]", short[].class); PRIMITIVE_ARRAY_CLASSES.put("char[]", char[].class); PRIMITIVE_ARRAY_CLASSES.put("int[]", int[].class); PRIMITIVE_ARRAY_CLASSES.put("long[]", long[].class); PRIMITIVE_ARRAY_CLASSES.put("float[]", float[].class); PRIMITIVE_ARRAY_CLASSES.put("double[]", double[].class); } private String type; public Object getAsObject(FacesContext context, UIComponent component, String value) { java.lang.reflect.Type objType; if (getType() == null) { ValueExpression expression = component.getValueExpression("value"); objType = expression.getType(context.getELContext()); } else { objType = getObjectType(getType().trim(), false); } return GsonConverter.getGson().fromJson(value, objType); } public String getAsString(FacesContext context, UIComponent component, Object value) { if (getType() == null) { return GsonConverter.getGson().toJson(value); } else { return GsonConverter.getGson().toJson(value, getObjectType(getType().trim(), false)); } } protected java.lang.reflect.Type getObjectType(String type, boolean isTypeArg) { Class clazz = PRIMITIVE_CLASSES.get(type); if (clazz != null) { if (!isTypeArg) { return clazz; } else { throw new ConverterException(new FacesMessage(FacesMessage.SEVERITY_ERROR, "Type argument can not be a primitive type, but it was " + type + ".", Constants.EMPTY_STRING)); } } clazz = PRIMITIVE_ARRAY_CLASSES.get(type); if (clazz != null) { return clazz; } int arrayBracketIdx = type.indexOf("["); int leftBracketIdx = type.indexOf("<"); if (arrayBracketIdx >= 0 && (leftBracketIdx < 0 || arrayBracketIdx < leftBracketIdx)) { // array try { clazz = Class.forName(type.substring(0, arrayBracketIdx)); return Array.newInstance(clazz, 0).getClass(); } catch (ClassNotFoundException e) { throw new ConverterException(new FacesMessage(FacesMessage.SEVERITY_ERROR, "Class " + type.substring(0, arrayBracketIdx) + " not found", Constants.EMPTY_STRING)); } } if (leftBracketIdx < 0) { try { return Class.forName(type); } catch (ClassNotFoundException e) { throw new ConverterException(new FacesMessage(FacesMessage.SEVERITY_ERROR, "Class " + type + " not found", Constants.EMPTY_STRING)); } } int rightBracketIdx = type.lastIndexOf(">"); if (rightBracketIdx < 0) { throw new ConverterException(new FacesMessage(FacesMessage.SEVERITY_ERROR, type + " is not a valid generic type.", Constants.EMPTY_STRING)); } Class rawType; try { rawType = Class.forName(type.substring(0, leftBracketIdx)); } catch (ClassNotFoundException e) { throw new ConverterException(new FacesMessage(FacesMessage.SEVERITY_ERROR, "Class " + type.substring(0, leftBracketIdx) + " not found", Constants.EMPTY_STRING)); } String strTypeArgs = type.substring(leftBracketIdx + 1, rightBracketIdx); List<String> listTypeArgs = new ArrayList<String>(); int startPos = 0; int seekPos = 0; while (true) { int commaPos = strTypeArgs.indexOf(",", seekPos); if (commaPos >= 0) { String term = strTypeArgs.substring(startPos, commaPos); int countLeftBrackets = StringUtils.countMatches(term, "<"); int countRightBrackets = StringUtils.countMatches(term, ">"); if (countLeftBrackets == countRightBrackets) { listTypeArgs.add(term.trim()); startPos = commaPos + 1; } seekPos = commaPos + 1; } else { listTypeArgs.add(strTypeArgs.substring(startPos).trim()); break; } } if (listTypeArgs.isEmpty()) { throw new ConverterException(new FacesMessage(FacesMessage.SEVERITY_ERROR, type + " is not a valid generic type.", Constants.EMPTY_STRING)); } int size = listTypeArgs.size(); java.lang.reflect.Type[] objectTypes = new java.lang.reflect.Type[size]; for (int i = 0; i < size; i++) { // recursive call for each type argument objectTypes[i] = getObjectType(listTypeArgs.get(i), true); } return new ParameterizedTypeImpl(rawType, objectTypes, null); } public String getType() { return type; } public void setType(String type) { this.type = type; } }