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The MongoDB Java Driver uber-artifact, containing mongodb-driver, mongodb-driver-core, and bson
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/*
* Copyright 2008-present 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 org.bson.types.Decimal128;
import org.bson.types.ObjectId;
import static java.lang.String.format;
import static java.util.Arrays.asList;
/**
* Abstract base class for BsonReader implementations.
*
* @since 3.0
*/
public abstract class AbstractBsonReader implements BsonReader {
private State state;
private Context context;
private BsonType currentBsonType;
private String currentName;
private boolean closed;
/**
* Initializes a new instance of the BsonReader class.
*/
protected AbstractBsonReader() {
state = State.INITIAL;
}
@Override
public BsonType getCurrentBsonType() {
return currentBsonType;
}
@Override
public String getCurrentName() {
if (state != State.VALUE) {
throwInvalidState("getCurrentName", State.VALUE);
}
return currentName;
}
/**
* Sets the type of the current value being read.
*
* @param newType the BSON Type.
*/
protected void setCurrentBsonType(final BsonType newType) {
currentBsonType = newType;
}
/**
* @return The current state of the reader.
*/
public State getState() {
return state;
}
/**
* Sets the new current state of this reader.
*
* @param newState the state to set this reader to.
*/
protected void setState(final State newState) {
state = newState;
}
/**
* Sets the field name for the key/value pair being read.
*
* @param newName the field name
*/
protected void setCurrentName(final String newName) {
currentName = newName;
}
/**
* Closes the reader.
*/
public void close() {
closed = true;
}
/**
* Return true if the reader has been closed.
*
* @return true if closed
*/
protected boolean isClosed() {
return closed;
}
/**
* Handles the logic to read binary data
*
* @return the BsonBinary value
*/
protected abstract BsonBinary doReadBinaryData();
/**
* Handles the logic to peek at the binary subtype.
*
* @return the binary subtype
*/
protected abstract byte doPeekBinarySubType();
/**
* Handles the logic to peek at the binary size.
*
* @return the binary size
* @since 3.4
*/
protected abstract int doPeekBinarySize();
/**
* Handles the logic to read booleans
*
* @return the boolean value
*/
protected abstract boolean doReadBoolean();
/**
* Handles the logic to read date time
*
* @return the long value
*/
protected abstract long doReadDateTime();
/**
* Handles the logic to read doubles
*
* @return the double value
*/
protected abstract double doReadDouble();
/**
* Handles the logic when reading the end of an array
*/
protected abstract void doReadEndArray();
/**
* Handles the logic when reading the end of a document
*/
protected abstract void doReadEndDocument();
/**
* Handles the logic to read 32 bit ints
*
* @return the int value
*/
protected abstract int doReadInt32();
/**
* Handles the logic to read 64 bit ints
*
* @return the long value
*/
protected abstract long doReadInt64();
/**
* Handles the logic to read Decimal128
*
* @return the Decimal128 value
* @since 3.4
*/
protected abstract Decimal128 doReadDecimal128();
/**
* Handles the logic to read Javascript functions
*
* @return the String value
*/
protected abstract String doReadJavaScript();
/**
* Handles the logic to read scoped Javascript functions
*
* @return the String value
*/
protected abstract String doReadJavaScriptWithScope();
/**
* Handles the logic to read a Max key
*/
protected abstract void doReadMaxKey();
/**
* Handles the logic to read a Min key
*/
protected abstract void doReadMinKey();
/**
* Handles the logic to read a null value
*/
protected abstract void doReadNull();
/**
* Handles the logic to read an ObjectId
*
* @return the ObjectId value
*/
protected abstract ObjectId doReadObjectId();
/**
* Handles the logic to read a regular expression
*
* @return the BsonRegularExpression value
*/
protected abstract BsonRegularExpression doReadRegularExpression();
/**
* Handles the logic to read a DBPointer
*
* @return the BsonDbPointer value
*/
protected abstract BsonDbPointer doReadDBPointer();
/**
* Handles the logic to read the start of an array
*/
protected abstract void doReadStartArray();
/**
* Handles the logic to read the start of a document
*/
protected abstract void doReadStartDocument();
/**
* Handles the logic to read a String
*
* @return the String value
*/
protected abstract String doReadString();
/**
* Handles the logic to read a Symbol
*
* @return the String value
*/
protected abstract String doReadSymbol();
/**
* Handles the logic to read a timestamp
*
* @return the BsonTimestamp value
*/
protected abstract BsonTimestamp doReadTimestamp();
/**
* Handles the logic to read an Undefined value
*/
protected abstract void doReadUndefined();
/**
* Handles any logic required to skip the name (reader must be positioned on a name).
*/
protected abstract void doSkipName();
/**
* Handles any logic required to skip the value (reader must be positioned on a value).
*/
protected abstract void doSkipValue();
@Override
public BsonBinary readBinaryData() {
checkPreconditions("readBinaryData", BsonType.BINARY);
setState(getNextState());
return doReadBinaryData();
}
@Override
public byte peekBinarySubType() {
checkPreconditions("readBinaryData", BsonType.BINARY);
return doPeekBinarySubType();
}
@Override
public int peekBinarySize() {
checkPreconditions("readBinaryData", BsonType.BINARY);
return doPeekBinarySize();
}
@Override
public boolean readBoolean() {
checkPreconditions("readBoolean", BsonType.BOOLEAN);
setState(getNextState());
return doReadBoolean();
}
@Override
public abstract BsonType readBsonType();
@Override
public long readDateTime() {
checkPreconditions("readDateTime", BsonType.DATE_TIME);
setState(getNextState());
return doReadDateTime();
}
@Override
public double readDouble() {
checkPreconditions("readDouble", BsonType.DOUBLE);
setState(getNextState());
return doReadDouble();
}
@Override
public void readEndArray() {
if (isClosed()) {
throw new IllegalStateException("BSONBinaryWriter");
}
if (getContext().getContextType() != BsonContextType.ARRAY) {
throwInvalidContextType("readEndArray", getContext().getContextType(), BsonContextType.ARRAY);
}
if (getState() == State.TYPE) {
readBsonType(); // will set state to EndOfArray if at end of array
}
if (getState() != State.END_OF_ARRAY) {
throwInvalidState("ReadEndArray", State.END_OF_ARRAY);
}
doReadEndArray();
setStateOnEnd();
}
@Override
public void readEndDocument() {
if (isClosed()) {
throw new IllegalStateException("BSONBinaryWriter");
}
if (getContext().getContextType() != BsonContextType.DOCUMENT && getContext().getContextType() != BsonContextType.SCOPE_DOCUMENT) {
throwInvalidContextType("readEndDocument",
getContext().getContextType(), BsonContextType.DOCUMENT, BsonContextType.SCOPE_DOCUMENT);
}
if (getState() == State.TYPE) {
readBsonType(); // will set state to EndOfDocument if at end of document
}
if (getState() != State.END_OF_DOCUMENT) {
throwInvalidState("readEndDocument", State.END_OF_DOCUMENT);
}
doReadEndDocument();
setStateOnEnd();
}
@Override
public int readInt32() {
checkPreconditions("readInt32", BsonType.INT32);
setState(getNextState());
return doReadInt32();
}
@Override
public long readInt64() {
checkPreconditions("readInt64", BsonType.INT64);
setState(getNextState());
return doReadInt64();
}
@Override
public Decimal128 readDecimal128() {
checkPreconditions("readDecimal", BsonType.DECIMAL128);
setState(getNextState());
return doReadDecimal128();
}
@Override
public String readJavaScript() {
checkPreconditions("readJavaScript", BsonType.JAVASCRIPT);
setState(getNextState());
return doReadJavaScript();
}
@Override
public String readJavaScriptWithScope() {
checkPreconditions("readJavaScriptWithScope", BsonType.JAVASCRIPT_WITH_SCOPE);
setState(State.SCOPE_DOCUMENT);
return doReadJavaScriptWithScope();
}
@Override
public void readMaxKey() {
checkPreconditions("readMaxKey", BsonType.MAX_KEY);
setState(getNextState());
doReadMaxKey();
}
@Override
public void readMinKey() {
checkPreconditions("readMinKey", BsonType.MIN_KEY);
setState(getNextState());
doReadMinKey();
}
@Override
public void readNull() {
checkPreconditions("readNull", BsonType.NULL);
setState(getNextState());
doReadNull();
}
@Override
public ObjectId readObjectId() {
checkPreconditions("readObjectId", BsonType.OBJECT_ID);
setState(getNextState());
return doReadObjectId();
}
@Override
public BsonRegularExpression readRegularExpression() {
checkPreconditions("readRegularExpression", BsonType.REGULAR_EXPRESSION);
setState(getNextState());
return doReadRegularExpression();
}
@Override
public BsonDbPointer readDBPointer() {
checkPreconditions("readDBPointer", BsonType.DB_POINTER);
setState(getNextState());
return doReadDBPointer();
}
@Override
public void readStartArray() {
checkPreconditions("readStartArray", BsonType.ARRAY);
doReadStartArray();
setState(State.TYPE);
}
@Override
public void readStartDocument() {
checkPreconditions("readStartDocument", BsonType.DOCUMENT);
doReadStartDocument();
setState(State.TYPE);
}
@Override
public String readString() {
checkPreconditions("readString", BsonType.STRING);
setState(getNextState());
return doReadString();
}
@Override
public String readSymbol() {
checkPreconditions("readSymbol", BsonType.SYMBOL);
setState(getNextState());
return doReadSymbol();
}
@Override
public BsonTimestamp readTimestamp() {
checkPreconditions("readTimestamp", BsonType.TIMESTAMP);
setState(getNextState());
return doReadTimestamp();
}
@Override
public void readUndefined() {
checkPreconditions("readUndefined", BsonType.UNDEFINED);
setState(getNextState());
doReadUndefined();
}
@Override
public void skipName() {
if (isClosed()) {
throw new IllegalStateException("This instance has been closed");
}
if (getState() != State.NAME) {
throwInvalidState("skipName", State.NAME);
}
setState(State.VALUE);
doSkipName();
}
@Override
public void skipValue() {
if (isClosed()) {
throw new IllegalStateException("BSONBinaryWriter");
}
if (getState() != State.VALUE) {
throwInvalidState("skipValue", State.VALUE);
}
doSkipValue();
setState(State.TYPE);
}
@Override
public BsonBinary readBinaryData(final String name) {
verifyName(name);
return readBinaryData();
}
@Override
public boolean readBoolean(final String name) {
verifyName(name);
return readBoolean();
}
@Override
public long readDateTime(final String name) {
verifyName(name);
return readDateTime();
}
@Override
public double readDouble(final String name) {
verifyName(name);
return readDouble();
}
@Override
public int readInt32(final String name) {
verifyName(name);
return readInt32();
}
@Override
public long readInt64(final String name) {
verifyName(name);
return readInt64();
}
@Override
public Decimal128 readDecimal128(final String name) {
verifyName(name);
return readDecimal128();
}
@Override
public String readJavaScript(final String name) {
verifyName(name);
return readJavaScript();
}
@Override
public String readJavaScriptWithScope(final String name) {
verifyName(name);
return readJavaScriptWithScope();
}
@Override
public void readMaxKey(final String name) {
verifyName(name);
readMaxKey();
}
@Override
public void readMinKey(final String name) {
verifyName(name);
readMinKey();
}
@Override
public String readName() {
if (state == State.TYPE) {
readBsonType();
}
if (state != State.NAME) {
throwInvalidState("readName", State.NAME);
}
state = State.VALUE;
return currentName;
}
@Override
public void readName(final String name) {
verifyName(name);
}
@Override
public void readNull(final String name) {
verifyName(name);
readNull();
}
@Override
public ObjectId readObjectId(final String name) {
verifyName(name);
return readObjectId();
}
@Override
public BsonRegularExpression readRegularExpression(final String name) {
verifyName(name);
return readRegularExpression();
}
@Override
public BsonDbPointer readDBPointer(final String name) {
verifyName(name);
return readDBPointer();
}
@Override
public String readString(final String name) {
verifyName(name);
return readString();
}
@Override
public String readSymbol(final String name) {
verifyName(name);
return readSymbol();
}
@Override
public BsonTimestamp readTimestamp(final String name) {
verifyName(name);
return readTimestamp();
}
@Override
public void readUndefined(final String name) {
verifyName(name);
readUndefined();
}
/**
* Throws an InvalidOperationException when the method called is not valid for the current ContextType.
*
* @param methodName The name of the method.
* @param actualContextType The actual ContextType.
* @param validContextTypes The valid ContextTypes.
* @throws BsonInvalidOperationException when the method called is not valid for the current ContextType.
*/
protected void throwInvalidContextType(final String methodName, final BsonContextType actualContextType,
final BsonContextType... validContextTypes) {
String validContextTypesString = StringUtils.join(" or ", asList(validContextTypes));
String message = format("%s can only be called when ContextType is %s, not when ContextType is %s.",
methodName, validContextTypesString, actualContextType);
throw new BsonInvalidOperationException(message);
}
/**
* Throws an InvalidOperationException when the method called is not valid for the current state.
*
* @param methodName The name of the method.
* @param validStates The valid states.
* @throws BsonInvalidOperationException when the method called is not valid for the current state.
*/
protected void throwInvalidState(final String methodName, final State... validStates) {
String validStatesString = StringUtils.join(" or ", asList(validStates));
String message = format("%s can only be called when State is %s, not when State is %s.",
methodName, validStatesString, state);
throw new BsonInvalidOperationException(message);
}
/**
* Verifies the current state and BSONType of the reader.
*
* @param methodName The name of the method calling this one.
* @param requiredBsonType The required BSON type.
*/
protected void verifyBSONType(final String methodName, final BsonType requiredBsonType) {
if (state == State.INITIAL || state == State.SCOPE_DOCUMENT || state == State.TYPE) {
readBsonType();
}
if (state == State.NAME) {
// ignore name
skipName();
}
if (state != State.VALUE) {
throwInvalidState(methodName, State.VALUE);
}
if (currentBsonType != requiredBsonType) {
throw new BsonInvalidOperationException(format("%s can only be called when CurrentBSONType is %s, "
+ "not when CurrentBSONType is %s.",
methodName, requiredBsonType, currentBsonType));
}
}
/**
* Verifies the name of the current element.
*
* @param expectedName The expected name.
* @throws BsonSerializationException when the name read is not the expected name
*/
protected void verifyName(final String expectedName) {
readBsonType();
String actualName = readName();
if (!actualName.equals(expectedName)) {
throw new BsonSerializationException(format("Expected element name to be '%s', not '%s'.",
expectedName, actualName));
}
}
/**
* Ensures any conditions are met before reading commences. Throws exceptions if the conditions are not met.
*
* @param methodName the name of the current method, which will indicate the field being read
* @param type the type of this field
*/
protected void checkPreconditions(final String methodName, final BsonType type) {
if (isClosed()) {
throw new IllegalStateException("BsonWriter is closed");
}
verifyBSONType(methodName, type);
}
/**
* Get the context, which will indicate which state the reader is in, for example which part of a document it's currently reading.
*
* @return the context
*/
protected Context getContext() {
return context;
}
/**
* Set the context, which will indicate which state the reader is in, for example which part of a document it's currently reading.
*
* @param context the current context.
*/
protected void setContext(final Context context) {
this.context = context;
}
/**
* Returns the next {@code State} to transition to, based on the {@link org.bson.AbstractBsonReader.Context} of this reader.
*
* @return the next state
*/
protected State getNextState() {
switch (context.getContextType()) {
case ARRAY:
case DOCUMENT:
case SCOPE_DOCUMENT:
return State.TYPE;
case TOP_LEVEL:
return State.DONE;
default:
throw new BSONException(format("Unexpected ContextType %s.", context.getContextType()));
}
}
private void setStateOnEnd() {
switch (getContext().getContextType()) {
case ARRAY:
case DOCUMENT:
setState(State.TYPE);
break;
case TOP_LEVEL:
setState(State.DONE);
break;
default:
throw new BSONException(format("Unexpected ContextType %s.", getContext().getContextType()));
}
}
protected class Mark implements BsonReaderMark {
private final State state;
private final Context parentContext;
private final BsonContextType contextType;
private final BsonType currentBsonType;
private final String currentName;
protected Context getParentContext() {
return parentContext;
}
protected BsonContextType getContextType() {
return contextType;
}
protected Mark() {
state = AbstractBsonReader.this.state;
parentContext = AbstractBsonReader.this.context.parentContext;
contextType = AbstractBsonReader.this.context.contextType;
currentBsonType = AbstractBsonReader.this.currentBsonType;
currentName = AbstractBsonReader.this.currentName;
}
public void reset() {
AbstractBsonReader.this.state = state;
AbstractBsonReader.this.currentBsonType = currentBsonType;
AbstractBsonReader.this.currentName = currentName;
}
}
/**
* The context for the reader. Records the parent context, creating a bread crumb trail to trace back up to the root context of the
* reader. Also records the {@link org.bson.BsonContextType}, indicating whether the reader is reading a document, array, or other
* complex sub-structure.
*/
protected abstract class Context {
private final Context parentContext;
private final BsonContextType contextType;
/**
* Creates a new instance.
*
* @param parentContext a possibly null value for the context that came before this one
* @param contextType the type of this context
*/
protected Context(final Context parentContext, final BsonContextType contextType) {
this.parentContext = parentContext;
this.contextType = contextType;
}
/**
* Returns the parent context. Allows users of this context object to transition to this parent context.
*
* @return the context that came before this one
*/
protected Context getParentContext() {
return parentContext;
}
/**
* Return the type of this context.
*
* @return the context type.
*/
protected BsonContextType getContextType() {
return contextType;
}
}
/**
* The state of a reader. Indicates where in a document the reader is.
*/
public enum State {
/**
* The initial state.
*/
INITIAL,
/**
* The reader is positioned at the type of an element or value.
*/
TYPE,
/**
* The reader is positioned at the name of an element.
*/
NAME,
/**
* The reader is positioned at a value.
*/
VALUE,
/**
* The reader is positioned at a scope document.
*/
SCOPE_DOCUMENT,
/**
* The reader is positioned at the end of a document.
*/
END_OF_DOCUMENT,
/**
* The reader is positioned at the end of an array.
*/
END_OF_ARRAY,
/**
* The reader has finished reading a document.
*/
DONE,
/**
* The reader is closed.
*/
CLOSED
}
}