Java tutorial
/* * Copyright (c) 2008-2014 MongoDB, Inc. * * 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.bson; import com.mongodb.util.JSONSerializers; import org.bson.types.BasicBSONList; import org.bson.types.ObjectId; import java.util.ArrayList; import java.util.Arrays; import java.util.Date; import java.util.LinkedHashMap; import java.util.List; import java.util.Map; import java.util.Set; import java.util.TreeSet; /** * A simple implementation of {@code DBObject}. A {@code DBObject} can be created as follows, using this class: {@code DBObject obj = new * BasicBSONObject(); obj.put( "foo", "bar" ); } */ @SuppressWarnings({ "rawtypes" }) public class BasicBSONObject extends LinkedHashMap<String, Object> implements BSONObject { private static final long serialVersionUID = -4415279469780082174L; /** * Creates an empty object. */ public BasicBSONObject() { } /** * Creates an empty object. * * @param size the initial capacity for the Map storing this document. */ public BasicBSONObject(final int size) { super(size); } /** * Creates a BSONObject initialised with a single key/value pair. * * @param key key under which to store * @param value value to store */ public BasicBSONObject(final String key, final Object value) { put(key, value); } /** * Creates a DBObject from a map. * * @param map map to convert */ @SuppressWarnings("unchecked") public BasicBSONObject(final Map map) { super(map); } /** * Converts a DBObject to a map. * * @return the DBObject */ public Map toMap() { return new LinkedHashMap<String, Object>(this); } /** * Deletes a field from this object. * * @param key the field name to remove * @return the object removed */ public Object removeField(final String key) { return remove(key); } /** * Checks if this object contains a given field * * @param field field name * @return if the field exists */ public boolean containsField(final String field) { return super.containsKey(field); } @Deprecated @Override public boolean containsKey(final String key) { return containsField(key); } /** * Gets a value from this object * * @param key field name * @return the value */ public Object get(final String key) { return super.get(key); } /** * Returns the value of a field as an {@code int}. * * @param key the field to look for * @return the field value (or default) */ public int getInt(final String key) { Object o = get(key); if (o == null) { throw new NullPointerException("no value for: " + key); } return toInt(o); } /** * Returns the value of a field as an {@code int}. * * @param key the field to look for * @param def the default to return * @return the field value (or default) */ public int getInt(final String key, final int def) { Object foo = get(key); if (foo == null) { return def; } return toInt(foo); } /** * Returns the value of a field as a {@code long}. * * @param key the field to return * @return the field value */ public long getLong(final String key) { Object foo = get(key); return ((Number) foo).longValue(); } /** * Returns the value of a field as an {@code long}. * * @param key the field to look for * @param def the default to return * @return the field value (or default) */ public long getLong(final String key, final long def) { Object foo = get(key); if (foo == null) { return def; } return ((Number) foo).longValue(); } /** * Returns the value of a field as a {@code double}. * * @param key the field to return * @return the field value */ public double getDouble(final String key) { Object foo = get(key); return ((Number) foo).doubleValue(); } /** * Returns the value of a field as an {@code double}. * * @param key the field to look for * @param def the default to return * @return the field value (or default) */ public double getDouble(final String key, final double def) { Object foo = get(key); if (foo == null) { return def; } return ((Number) foo).doubleValue(); } /** * Returns the value of a field as a string * * @param key the field to look up * @return the value of the field, converted to a string */ public String getString(final String key) { Object foo = get(key); if (foo == null) { return null; } return foo.toString(); } /** * Returns the value of a field as a string * * @param key the field to look up * @param def the default to return * @return the value of the field, converted to a string */ public String getString(final String key, final String def) { Object foo = get(key); if (foo == null) { return def; } return foo.toString(); } /** * Returns the value of a field as a boolean. * * @param key the field to look up * @return the value of the field, or false if field does not exist */ public boolean getBoolean(final String key) { return getBoolean(key, false); } /** * Returns the value of a field as a boolean * * @param key the field to look up * @param def the default value in case the field is not found * @return the value of the field, converted to a string */ public boolean getBoolean(final String key, final boolean def) { Object foo = get(key); if (foo == null) { return def; } if (foo instanceof Number) { return ((Number) foo).intValue() > 0; } if (foo instanceof Boolean) { return (Boolean) foo; } throw new IllegalArgumentException("can't coerce to bool:" + foo.getClass()); } /** * Returns the object id or null if not set. * * @param field The field to return * @return The field object value or null if not found (or if null :-^). */ public ObjectId getObjectId(final String field) { return (ObjectId) get(field); } /** * Returns the object id or def if not set. * * @param field The field to return * @param def the default value in case the field is not found * @return The field object value or def if not set. */ public ObjectId getObjectId(final String field, final ObjectId def) { Object foo = get(field); return (foo != null) ? (ObjectId) foo : def; } /** * Returns the date or null if not set. * * @param field The field to return * @return The field object value or null if not found. */ public Date getDate(final String field) { return (Date) get(field); } /** * Returns the date or def if not set. * * @param field The field to return * @param def the default value in case the field is not found * @return The field object value or def if not set. */ public Date getDate(final String field, final Date def) { Object foo = get(field); return (foo != null) ? (Date) foo : def; } @SuppressWarnings("unchecked") @Override public void putAll(final Map m) { for (final Map.Entry entry : (Set<Map.Entry>) m.entrySet()) { put(entry.getKey().toString(), entry.getValue()); } } @Override public void putAll(final BSONObject o) { for (final String k : o.keySet()) { put(k, o.get(k)); } } /** * Add a key/value pair to this object * * @param key the field name * @param val the field value * @return {@code this} */ public BasicBSONObject append(final String key, final Object val) { put(key, val); return this; } /** * Returns a JSON serialization of this object * * @return JSON serialization */ @Override public String toString() { return JSONSerializers.getStrict().serialize(this); } /** * Compares two documents according to their serialized form, ignoring the order of keys. * * @param o the document to compare to, which must be an instance of {@link org.bson.BSONObject}. * @return true if the documents have the same serialized form, ignoring key order. */ @Override public boolean equals(final Object o) { if (o == this) { return true; } if (!(o instanceof BSONObject)) { return false; } BSONObject other = (BSONObject) o; if (!keySet().equals(other.keySet())) { return false; } return Arrays.equals(canonicalizeBSONObject(this).encode(), canonicalizeBSONObject(other).encode()); } @Override public int hashCode() { return Arrays.hashCode(canonicalizeBSONObject(this).encode()); } private byte[] encode() { return new BasicBSONEncoder().encode(this); } // create a copy of "from", but with keys ordered alphabetically @SuppressWarnings("unchecked") private static Object canonicalize(final Object from) { if (from instanceof BSONObject && !(from instanceof BasicBSONList)) { return canonicalizeBSONObject((BSONObject) from); } else if (from instanceof List) { return canonicalizeList((List<Object>) from); } else if (from instanceof Map) { return canonicalizeMap((Map<String, Object>) from); } else { return from; } } private static Map<String, Object> canonicalizeMap(final Map<String, Object> from) { Map<String, Object> canonicalized = new LinkedHashMap<String, Object>(from.size()); TreeSet<String> keysInOrder = new TreeSet<String>(from.keySet()); for (String key : keysInOrder) { Object val = from.get(key); canonicalized.put(key, canonicalize(val)); } return canonicalized; } private static BasicBSONObject canonicalizeBSONObject(final BSONObject from) { BasicBSONObject canonicalized = new BasicBSONObject(); TreeSet<String> keysInOrder = new TreeSet<String>(from.keySet()); for (String key : keysInOrder) { Object val = from.get(key); canonicalized.put(key, canonicalize(val)); } return canonicalized; } private static List canonicalizeList(final List<Object> list) { List<Object> canonicalized = new ArrayList<Object>(list.size()); for (Object cur : list) { canonicalized.add(canonicalize(cur)); } return canonicalized; } private int toInt(final Object o) { if (o instanceof Number) { return ((Number) o).intValue(); } if (o instanceof Boolean) { return ((Boolean) o) ? 1 : 0; } throw new IllegalArgumentException("can't convert: " + o.getClass().getName() + " to int"); } }