com.strato.hidrive.api.JSONDataReader.java Source code

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Here is the source code for com.strato.hidrive.api.JSONDataReader.java

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/**
* Copyright 2014 STRATO AG
* 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 com.strato.hidrive.api;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.strato.hidrive.api.interfaces.DataReader;

public class JSONDataReader implements DataReader {

    interface ElementValue<T> {
        public T value(JsonElement jsonElement);
    }

    private JsonObject jsonObject;

    public void setJsonObject(JsonObject jsonObject) {
        this.jsonObject = jsonObject;
    }

    public JSONDataReader(JsonObject jsonObject) {
        this.jsonObject = jsonObject;
    }

    private <T> T get(String name, T defaultValue, ElementValue<T> elementValue) {
        return isFieldExists(name) ? elementValue.value(jsonObject.get(name)) : defaultValue;
    }

    @Override
    public int readIntWithName(String name) {
        int defaultValue = 0;
        return get(name, defaultValue, new ElementValue<Integer>() {
            @Override
            public Integer value(JsonElement jsonElement) {
                return jsonElement.getAsInt();
            }
        });
    }

    @Override
    public long readLongWithName(String name) {
        long defaultValue = 0L;
        return get(name, defaultValue, new ElementValue<Long>() {
            @Override
            public Long value(JsonElement jsonElement) {
                return jsonElement.getAsLong();
            }
        });
    }

    @Override
    public boolean readBooleanWithName(String name) {
        boolean defaultValue = false;
        return get(name, defaultValue, new ElementValue<Boolean>() {
            @Override
            public Boolean value(JsonElement jsonElement) {
                return jsonElement.getAsBoolean();
            }
        });
    }

    @Override
    public String readStringWithName(String name) {
        String defaultValue = "";
        return get(name, defaultValue, new ElementValue<String>() {
            @Override
            public String value(JsonElement jsonElement) {
                return jsonElement.getAsString();
            }
        });
    }

    @Override
    public Date readDateWithName(String name) {
        return null;
    }

    @Override
    public DataReader readDataReaderWithName(String name) {
        if (!isFieldExists(name)) {
            return null;
        }
        JsonObject defaultValue = null;
        return new JSONDataReader(get(name, defaultValue, new ElementValue<JsonObject>() {
            @Override
            public JsonObject value(JsonElement jsonElement) {
                return jsonElement.getAsJsonObject();
            }
        }));
    }

    @Override
    public List<DataReader> readDataReaderListWithName(String name) {
        if (!isFieldExists(name)) {
            return null;
        }

        JsonArray defaultValue = null;
        JsonArray array = get(name, defaultValue, new ElementValue<JsonArray>() {
            @Override
            public JsonArray value(JsonElement jsonElement) {
                return jsonElement.getAsJsonArray();
            }
        });

        List<DataReader> dataReaders = new ArrayList<DataReader>();
        for (JsonElement jsonObject : array) {
            dataReaders.add(new JSONDataReader((JsonObject) jsonObject));
        }
        return dataReaders;

    }

    @Override
    public String readStringValue() {
        return null;
    }

    @Override
    public double readDoubleWithName(String name) {
        double defaultValue = 0D;
        return get(name, defaultValue, new ElementValue<Double>() {
            @Override
            public Double value(JsonElement jsonElement) {
                return jsonElement.getAsDouble();
            }
        });
    }

    @Override
    public boolean isFieldExists(String name) {
        return jsonObject.has(name) && !jsonObject.get(name).isJsonNull();
    }

}