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With inspiration from other libraries
The newest version!
/*
*
* Copyright 2015 Jonathan Shook
*
* 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 io.virtdata.core;
//
import io.virtdata.api.DataMapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.*;
/**
* Maps a template with named bind points and specifiers onto a set of data
* mapping function instances. Allows for streamlined calling of mapper functions
* as a set.
* There are several ways to get generated data via this class. You must always
* provide a base input value. Fields can be accessed by parameter position or name.
* In some cases, you can provide an iterator stride
* in order to get data in bulk. In other cases, you can have setters called
* directly on your provided objects. See the detailed method docs for more information.
*/
public class Bindings {
private final static Logger logger = LoggerFactory.getLogger(Bindings.class);
private BindingsTemplate template;
private List> dataMappers = new ArrayList>();
private ThreadLocal>> nameCache;
public Bindings(BindingsTemplate template, List> dataMappers) {
this.template = template;
this.dataMappers = dataMappers;
nameCache = ThreadLocal.withInitial(() ->
new HashMap>() {{
for (int i = 0; i < template.getBindPointNames().size(); i++) {
put(template.getBindPointNames().get(i), dataMappers.get(i));
}
}});
}
public String toString() {
return template.toString() + dataMappers;
}
/**
* Get a value from each data mapper in the bindings list
*
* @param input The long value which the bound data mappers will use as in input
* @return An array of objects, the values yielded from each data mapper in the bindings list
*/
public Object[] getAll(long input) {
Object[] values = new Object[dataMappers.size()];
int offset = 0;
for (DataMapper dataMapper : dataMappers) {
values[offset++] = dataMapper.get(input);
}
return values;
}
/**
* @return {@link BindingsTemplate} associated with this set of bindings
*/
public BindingsTemplate getTemplate() {
return this.template;
}
/**
* @param input The input value for which the values should be generated.
* @return {@link Map} of {@link String} to {@link Object}
*/
public Map getAllMap(long input) {
Map values = new HashMap<>();
setMap(values, input);
return values;
}
/**
* Generate a list of maps over a range of inputs.
* For example, calling getIteratedMaps(5,3) with bindings named
* alpha and gamma might produce something like:
*
* -
*
* - alpha -> val1
* - gamma -> val2
*
*
* -
*
* - alpha -> val3
* - gamma -> val4
*
*
* -
*
* - alpha -> val5
* - gamma -> val6
*
*
*
*
* @param input The base value for which the values should be generated.
* @param count The number of iterations, starting at input, to be generated
* @return {@link List} of {@link Map} of {@link String} to {@link Object}
*/
public List> getIteratedMaps(long input, int count) {
List> listOfMaps = new ArrayList<>(count);
for (int i = 0; i < count; i++) {
Map suffixedMap = new HashMap<>();
setMap(suffixedMap, input + i);
listOfMaps.add(suffixedMap);
}
return listOfMaps;
}
/**
* Generate a map containing the results from multiple iterations, suffixing
* the keys in the map with the iterations from 0 to count-1.
* For example, calling getIteratedSuffixMap(5, 3) with generators named
* alpha and gamma might yield results like
*
* - alpha0 -> val1
* - gamma0 -> val2
* - alpha1 -> val3
* - gamma1 -> val4
* - alpha2 -> val5
* - gamma2 -> val6
*
*
* @param input The base input value for which the values should be generated
* @param count The count of maps that should be added to the final map
* @return {@link Map} of {@link String} to {@link Object}
*/
public Map getIteratedSuffixMap(long input, int count) {
Map suffixedMap = new LinkedHashMap<>(count * this.dataMappers.size());
setIteratedSuffixMap(suffixedMap, input, count);
return suffixedMap;
}
/**
* This is a version of the {@link #setIteratedSuffixMap(Map, long, int, String[])} which creates
* a new map for each call.
* @param input The base input value for which the values should be generated
* @param count The count of maps that should be added to the final map
* @param fieldNames The field names which are used to look up the functions in the binding
* @return A newly created map with the generated names and values.
*/
public Map getIteratedSuffixMap(long input, int count, String... fieldNames) {
Map suffixedMap = new LinkedHashMap<>(count * fieldNames.length);
setIteratedSuffixMap(suffixedMap, input, count, fieldNames);
return suffixedMap;
}
/**
* Populate a map of values with a two-dimensional set of generated key and value names. This is a basic
* traversal over all the provided field names and a range of input values from input to input+count.
* The key names for the map are created by adding a numeric suffix to the field name.
*
* For example, with field names aleph and gamma, with input 53 and count 2, the key names will
* be created as aleph0, gamma0, aleph1, gamma1, and the input values which will be used to
* create the generated values for these keys will be 53, 53, and 54, 54, respectively.
*
* Symbolically, this does the same as the sketch below:
*
*
* - map{aleph0}=funcFor("aleph")(53)
* - map{gamma0}=funcFor("gamma")(53)
* - map{aleph1}=funcFor("aleph")(54)
* - map{gamma1}=funcFor("gamma")(54)
*
*
* @param suffixedMap A donor map which is to be populated. The values do not clear the map, but merely overwrite
* values of the same name.
* @param input The base input value for which the values should be generated
* @param count The count of maps that should be added to the final map
* @param fieldNames The field names which are used to look up the functions in the binding
*/
private void setIteratedSuffixMap(Map suffixedMap, long input, int count, String[] fieldNames) {
for (int i = 0; i < count; i++) {
for (String f : fieldNames) {
suffixedMap.put(f+i,get(f,input+i));
}
}
}
/**
* Get a value for the data mapper in slot i
*
* @param i the data mapper slot, 0-indexed
* @param input the long input value which the bound data mapper will use as input
* @return a single object, the value yielded from the indexed data mapper in the bindings list
*/
public Object get(int i, long input) {
return dataMappers.get(i).get(input);
}
/**
* Get a value for the cached mapper name, using the name to mapper index cache.
* @param name The field name in the data mapper
* @param input the long input value which the bound data mapper will use as an input
* @return a single object, the value yielded from the named and indexed data mapper in the bindings list.
*/
public Object get(String name, long input) {
DataMapper dataMapper = nameCache.get().get(name);
return dataMapper.get(input);
}
/**
* Generate all values in the bindings template, and set each of them in
* the map according to their bind point name.
*
* @param donorMap - a user-provided Map<String,Object>
* @param cycle - the cycle for which to generate the values
*/
public void setMap(Map donorMap, long cycle) {
Object[] all = getAll(cycle);
for (int i = 0; i < all.length; i++) {
donorMap.put(template.getBindPointNames().get(i), all[i]);
}
}
/**
* Set the values in a provided map, with bound names suffixed with
* some value. No non-overlapping keys in the map will be affected.
*
* @param donorMap an existing {@link Map} of {@link String} to {@link Object}
* @param cycle the cycle for which values should be generated
* @param suffix a string suffix to be appended to any map keys
*/
public void setSuffixedMap(Map donorMap, long cycle, String suffix) {
Object[] all = getAll(cycle);
for (int i = 0; i < all.length; i++) {
donorMap.put(template.getBindPointNames().get(i) + suffix, all[i]);
}
}
/**
* Set the values in a provided map, with the bound names suffixed with
* an internal iteration value.
*
* @param donorMap an existing {@link Map} of {@link String} to {@link Object}
* @param input the base cycle for which values should be generated
* @param count the number of iterations to to generate values and keynames for
*/
public void setIteratedSuffixMap(Map donorMap, long input, long count) {
for (int i = 0; i < count; i++) {
setSuffixedMap(donorMap, input + i, String.valueOf(i));
}
}
/**
* Generate only the values which have matching keys in the provided
* map according to their bind point names, and assign them to the
* map under that name. It is an error for a key name to be defined
* in the map for which there is no mapper.
*
* @param donorMap - a user-provided Map<String,Object>
* @param input - the input for which to generate the values
*/
public void updateMap(Map donorMap, long input) {
for (String s : donorMap.keySet()) {
donorMap.put(s, get(s, input));
}
}
/**
* Generate only the values named in fieldNames, and then call the user-provided
* field setter for each name and object generated.
*
* @param fieldSetter user-provided object that implements {@link FieldSetter}.
* @param input the input for which to generate values
* @param fieldName A varargs list of field names, or a String[] of names to set
*/
public void setNamedFields(FieldSetter fieldSetter, long input, String... fieldName) {
for (String s : fieldName) {
fieldSetter.setField(s, get(s, input));
}
}
/**
* Generate all the values named in the bindings for a number of iterations, calling
* a user-provided field setter for each name and object generated, with the
* iteration number appended to the fieldName, but only for the named bindings.
*
* @param fieldSetter user-provided object that implements {@link FieldSetter}
* @param input the base input value for which the objects should be generated
* @param count the number of iterations to generate values and names for
* @param fieldName the field names for which to generate values and names
*/
public void setNamedFieldsIterated(FieldSetter fieldSetter, long input, int count, String... fieldName) {
for (int i = 0; i < count; i++) {
for (String s : fieldName) {
fieldSetter.setField(s + i, get(s, input + i));
}
}
}
/**
* Generate all the values named in the bind point names, then call the user-provided
* field setter for each name and object generated.
*
* @param fieldSetter user-provided object that implements {@link FieldSetter}
* @param input the input for which to generate values
*/
public void setAllFields(FieldSetter fieldSetter, long input) {
Object[] all = getAll(input);
for (int i = 0; i < all.length; i++) {
fieldSetter.setField(template.getBindPointNames().get(i), all[i]);
}
}
/**
* Generate all the values named in the bindings for a number of iterations, calling
* a user-provided field setter for each name and object generated, with the
* iteration number appended to the fieldName.
*
* @param fieldSetter user-provided object that implements {@link FieldSetter}
* @param input the base input value for which the objects should be generated
* @param count the number of iterations to generate values and names for
*/
public void setAllFieldsIterated(FieldSetter fieldSetter, long input, int count) {
for (int i = 0; i < count; i++) {
Object[] all = getAll(input+i);
for (int j = 0; j < all.length; j++) {
fieldSetter.setField(template.getBindPointNames().get(i) + i, all[i]);
}
}
}
public LazyValuesMap getLazyMap(long input) {
return new LazyValuesMap(this, input);
}
public static interface FieldSetter {
void setField(String name, Object value);
}
}