/*******************************************************************************
* Copyright (c) 2008, 2013 EclipseSource.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Ralf Sternberg - initial implementation and API
******************************************************************************/
package com.eclipsesource.json;
import java.io.IOException;
import java.io.Reader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
/**
* Represents a JSON array. A JSON array is a sequence of elements, which are JSON values (see
* {@link JsonValue}).
* <p>
* Elements can be added using one of the different <code>add(...)</code> methods. Accepted values
* are either instances of {@link JsonValue}, or strings, primitive numbers, or boolean values.
* </p>
* <p>
* Elements can be accessed by their index using {@link #get(int)}. This class also supports
* iterating over the elements in document order using an {@link #iterator()} or an enhanced for
* loop:
* </p>
*
* <pre>
* for( JsonValue value : jsonArray ) {
* ...
* }
* </pre>
* <p>
* A n equivalent {@link List} can be obtained from the method {@link #values()}.
* </p>
* <p>
* Note that this class is <strong>not thread-safe</strong>. If multiple threads access a
* <code>JsonArray</code> instance concurrently, while at least one of these threads modifies the
* contents of this array, access to the instance must be synchronized externally. Failure to do so
* may lead to an inconsistent state.
* </p>
* <p>
* This class is <strong>not supposed to be extended</strong> by clients.
* </p>
*/
@SuppressWarnings( "serial" ) // use default serial UID
public class JsonArray extends JsonValue implements Iterable<JsonValue> {
private final List<JsonValue> values;
/**
* Creates a new empty JsonArray.
*/
public JsonArray() {
values = new ArrayList<JsonValue>();
}
/**
* Creates a new JsonArray with the contents of the specified JSON array.
*
* @param array
* the JsonArray to get the initial contents from, must not be <code>null</code>
*/
public JsonArray( JsonArray array ) {
this( array, false );
}
private JsonArray( JsonArray array, boolean unmodifiable ) {
if( array == null ) {
throw new NullPointerException( "array is null" );
}
if( unmodifiable ) {
values = Collections.unmodifiableList( array.values );
} else {
values = new ArrayList<JsonValue>( array.values );
}
}
/**
* Reads a JSON array from the given reader.
*
* @param reader
* the reader to read the JSON array from
* @return the JSON array that has been read
* @throws IOException
* if an I/O error occurs in the reader
* @throws ParseException
* if the input is not valid JSON
* @throws UnsupportedOperationException
* if the input does not contain a JSON array
*/
public static JsonArray readFrom( Reader reader ) throws IOException {
return JsonValue.readFrom( reader ).asArray();
}
/**
* Reads a JSON array from the given string.
*
* @param string
* the string that contains the JSON array
* @return the JSON array that has been read
* @throws ParseException
* if the input is not valid JSON
* @throws UnsupportedOperationException
* if the input does not contain a JSON array
*/
public static JsonArray readFrom( String string ) {
return JsonValue.readFrom( string ).asArray();
}
/**
* Returns an unmodifiable wrapper for the specified JsonArray. This method allows to provide
* read-only access to a JsonArray.
* <p>
* The returned JsonArray is backed by the given array and reflects subsequent changes. Attempts
* to modify the returned JsonArray result in an <code>UnsupportedOperationException</code>.
* </p>
*
* @param array
* the JsonArray for which an unmodifiable JsonArray is to be returned
* @return an unmodifiable view of the specified JsonArray
*/
public static JsonArray unmodifiableArray( JsonArray array ) {
return new JsonArray( array, true );
}
/**
* Adds the JSON representation of the specified <code>long</code> value to the array.
*
* @param value
* the value to add to the array
* @return the array itself, to enable method chaining
*/
public JsonArray add( long value ) {
values.add( valueOf( value ) );
return this;
}
/**
* Adds the JSON representation of the specified <code>float</code> value to the array.
*
* @param value
* the value to add to the array
* @return the array itself, to enable method chaining
*/
public JsonArray add( float value ) {
values.add( valueOf( value ) );
return this;
}
/**
* Adds the JSON representation of the specified <code>double</code> value to the array.
*
* @param value
* the value to add to the array
* @return the array itself, to enable method chaining
*/
public JsonArray add( double value ) {
values.add( valueOf( value ) );
return this;
}
/**
* Adds the JSON representation of the specified <code>boolean</code> value to the array.
*
* @param value
* the value to add to the array
* @return the array itself, to enable method chaining
*/
public JsonArray add( boolean value ) {
values.add( valueOf( value ) );
return this;
}
/**
* Adds the JSON representation of the specified string to the array.
*
* @param value
* the string to add to the array
* @return the array itself, to enable method chaining
*/
public JsonArray add( String value ) {
values.add( valueOf( value ) );
return this;
}
/**
* Adds the specified JsonValue to the array.
*
* @param value
* the JsonValue to add to the array
* @return the array itself, to enable method chaining
*/
public JsonArray add( JsonValue value ) {
if( value == null ) {
throw new NullPointerException( "value is null" );
}
values.add( value );
return this;
}
/**
* Returns the number of elements in this array.
*
* @return the number of elements in this array
*/
public int size() {
return values.size();
}
/**
* Returns <code>true</code> if this array contains no elements.
*
* @return <code>true</code> if this array contains no elements
*/
public boolean isEmpty() {
return values.isEmpty();
}
/**
* Returns the value of the element at the specified position in this array.
*
* @param index
* the index of the array element to return
* @return the value of the element at the specified position
* @throws IndexOutOfBoundsException
* if the index is out of range (index < 0 || index >= size()).
*/
public JsonValue get( int index ) {
return values.get( index );
}
/**
* Returns a list of the values in this array in document order. The returned list is backed by
* this array and will reflect subsequent changes. It cannot be used to modify this array.
* Attempts to modify the returned list will result in an exception.
*
* @return a list of the values in this array
*/
public List<JsonValue> values() {
return Collections.unmodifiableList( values );
}
/**
* Returns an iterator over the values of this array in document order. The returned iterator
* cannot be used to modify this array.
*
* @return an iterator over the values of this array
*/
public Iterator<JsonValue> iterator() {
return Collections.unmodifiableList( values ).iterator();
}
@Override
protected void write( JsonWriter writer ) throws IOException {
writer.writeBeginArray();
int length = values.size();
for( int i = 0; i < length; i++ ) {
if( i != 0 ) {
writer.writeArrayValueSeparator();
}
values.get( i ).write( writer );
}
writer.writeEndArray();
}
@Override
public boolean isArray() {
return true;
}
@Override
public JsonArray asArray() {
return this;
}
@Override
public int hashCode() {
return values.hashCode();
}
@Override
public boolean equals( Object object ) {
if( this == object ) {
return true;
}
if( object == null ) {
return false;
}
if( getClass() != object.getClass() ) {
return false;
}
JsonArray other = (JsonArray)object;
return values.equals( other.values );
}
}