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com.signalfx.shaded.fasterxml.jackson.jr.ob.api.MapBuilder Maven / Gradle / Ivy

package com.signalfx.shaded.fasterxml.jackson.jr.ob.api;

import java.util.*;

import com.signalfx.shaded.fasterxml.jackson.jr.ob.JSON;
import com.signalfx.shaded.fasterxml.jackson.jr.ob.JSON.Feature;
import com.signalfx.shaded.fasterxml.jackson.jr.ob.impl.DeferredMap;
import com.signalfx.shaded.fasterxml.jackson.jr.ob.JSONObjectException;

/**
 * Helper class that is used for constructing {@link java.util.Map}s
 * to map JSON Object values in.
 *

* Objects server both as "factories" for creating new builders (blueprint * style), and as actual builders. For each distinct read operation, * {@link #newBuilder} will be called at least once; this instance * may be used and reused multiple times, as calling {@link #start} * will reset the state so that more {@link List}s may be built. */ public abstract class MapBuilder { protected final int _features; protected final boolean _checkDups; /** * Optional {@link Map} implementation class, used when specific * implementation is desired. */ protected final Class _mapType; protected MapBuilder(int features, Class type) { _features = features; _checkDups = JSON.Feature.FAIL_ON_DUPLICATE_MAP_KEYS.isEnabled(features); _mapType = type; } /** * Factory method for getting a blueprint instance of the default * {@link MapBuilder} implementation. */ public static MapBuilder defaultImpl() { return new Default(0, null); } public abstract MapBuilder newBuilder(int features); public abstract MapBuilder newBuilder(Class mapImpl); public MapBuilder newBuilder() { return newBuilder(_features); } public final boolean isEnabled(JSON.Feature f) { return f.isEnabled(_features); } public abstract MapBuilder start(); public abstract MapBuilder put(String key, Object value); public abstract Map build(); /** * Specialized method that is called when an empty list needs to * be constructed; this may be a new list, or an immutable shared * List, depending on implementation. *

* Default implementation simply calls: *

     *  start().build();
     *
* which assumes that a builder has been constructed with {@link #newBuilder} */ public Map emptyMap() throws JSONObjectException { return start().build(); } /** * Specialized method that is called when an empty list needs to * be constructed; this may be a new list, or an immutable shared * List, depending on implementation. *

* Default implementation simply calls: *

     *  start().put(key, value).build();
     *
*/ public Map singletonMap(String key, Object value) throws JSONObjectException { return start().put(key, value).build(); } /* /********************************************************** /* Default implementation /********************************************************** */ /** * Default {@link MapBuilder} implementation which builds * either {@link HashMap} or {@link LinkedHashMap} instances * (depending on {@link Feature#PRESERVE_FIELD_ORDERING}). * It may also, with alternate configuration, * use {@link Collections#emptyMap()} for empty Maps, * if allowed with {@link Feature#READ_ONLY}. */ public static class Default extends MapBuilder { protected Map _current; protected Default(int features, Class type) { super(features, type); } @Override public MapBuilder newBuilder(int features) { return new Default(features, _mapType); } @Override public MapBuilder newBuilder(Class mapImpl) { return new Default(_features, mapImpl); } @Override public MapBuilder start() { // If this builder is "busy", create a new one... if (_current != null) { return newBuilder().start(); } _current = _map(12); return this; } @Override public Map build() { Map result = _current; _current = null; return result; } @Override public MapBuilder put(String key, Object value) { if (_checkDups) { if (_current.containsKey(key)) { // 14-Apr-2017, tatu: Note that choice of `IllegalArgumentException` is arbitrary // but not random: caller catches and re-packages it to give context throw new IllegalArgumentException("Duplicate key (key '"+key+"')"); } } _current.put(key, value); return this; } @Override public Map emptyMap() { if ((_mapType == null) && isEnabled(Feature.READ_ONLY)) { return Collections.emptyMap(); } return _map(4); } private final Map _map(int initialSize) { if (_mapType != null) { try { @SuppressWarnings("unchecked") Map m = (Map) _mapType.getDeclaredConstructor().newInstance((Object[]) null); return m; } catch (Exception e) { Throwable t = e; while (t.getCause() != null) { t = t.getCause(); } throw new IllegalArgumentException("Failed to create an instance of " +_mapType.getName()+" ("+t.getClass().getName()+"): "+t.getMessage()); } } final boolean sort = isEnabled(Feature.PRESERVE_FIELD_ORDERING); if (isEnabled(Feature.USE_DEFERRED_MAPS)) { return new DeferredMap(sort, initialSize); } return sort ? new LinkedHashMap(initialSize) : new HashMap(initialSize); } } }




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