attributes.java

JAVA基本类源代码,大家可以学习学习!

/*
 * @(#)Attributes.java	1.45 03/01/23
 *
 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package java.util.jar;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.Collection;
import java.util.AbstractSet;
import java.util.Iterator;
import java.util.logging.Logger; 

/**
 * The Attributes class maps Manifest attribute names to associated string
 * values. Valid attribute names are case-insensitive, are restricted to 
 * the ASCII characters in the set [0-9a-zA-Z_-], and cannot exceed 70 
 * characters in length. Attribute values can contain any characters and 
 * will be UTF8-encoded when written to the output stream.  See the 
 * <a href="../../../../guide/jar/jar.html">JAR File Specification</a> 
 * for more information about valid attribute names and values.
 *
 * @author  David Connelly
 * @version 1.45, 01/23/03
 * @see	    Manifest
 * @since   1.2
 */
public class Attributes implements Map, Cloneable {
    /**
     * The attribute name-value mappings.
     */
    protected Map map;

    /**
     * Constructs a new, empty Attributes object with default size.
     */
    public Attributes() {
	this(11);
    }

    /**
     * Constructs a new, empty Attributes object with the specified
     * initial size.
     *
     * @param size the initial number of attributes
     */
    public Attributes(int size) {
	map = new HashMap(size);
    }

    /**
     * Constructs a new Attributes object with the same attribute name-value
     * mappings as in the specified Attributes.
     *
     * @param attr the specified Attributes
     */
    public Attributes(Attributes attr) {
	map = new HashMap(attr);
    }


    /**
     * Returns the value of the specified attribute name, or null if the
     * attribute name was not found.
     *
     * @param name the attribute name
     * @return the value of the specified attribute name, or null if
     *         not found.
     */
    public Object get(Object name) {
	return map.get(name);
    }

    /**
     * Returns the value of the specified attribute name, specified as
     * a string, or null if the attribute was not found. The attribute
     * name is case-insensitive.
     * <p>
     * This method is defined as:
     * <pre>
     *	    return (String)get(new Attributes.Name((String)name));
     * </pre>
     *
     * @param name the attribute name as a string
     * @return the String value of the specified attribute name, or null if
     *         not found.
     * @throws IllegalArgumentException if the attribute name is invalid
     */
    public String getValue(String name) {
        return (String)get(new Attributes.Name((String)name));
    }

    /**
     * Returns the value of the specified Attributes.Name, or null if the
     * attribute was not found.
     * <p>
     * This method is defined as:
     * <pre>
     *     return (String)get(name);
     * </pre>
     *
     * @param name the Attributes.Name object
     * @return the String value of the specified Attribute.Name, or null if
     *         not found.
     */
    public String getValue(Name name) {
	return (String)get(name);
    }

    /**
     * Associates the specified value with the specified attribute name
     * (key) in this Map. If the Map previously contained a mapping for
     * the attribute name, the old value is replaced.
     *
     * @param name the attribute name
     * @param value the attribute value
     * @return the previous value of the attribute, or null if none
     * @exception ClassCastException if the name is not a Attributes.Name
     *            or the value is not a String
     */
    public Object put(Object name, Object value) {
        return map.put((Attributes.Name)name, (String)value);
    }

    /**
     * Associates the specified value with the specified attribute name,
     * specified as a String. The attributes name is case-insensitive.
     * If the Map previously contained a mapping for the attribute name,
     * the old value is replaced.
     * <p>
     * This method is defined as:
     * <pre>
     *	    return (String)put(new Attributes.Name(name), value);
     * </pre>
     *
     * @param name the attribute name as a string
     * @param value the attribute value
     * @return the previous value of the attribute, or null if none
     * @exception IllegalArgumentException if the attribute name is invalid
     */
    public String putValue(String name, String value) {
	return (String)put(new Name(name), value);
    }

    /**
     * Removes the attribute with the specified name (key) from this Map.
     * Returns the previous attribute value, or null if none.
     *
     * @param name attribute name
     * @return the previous value of the attribute, or null if none
     */
    public Object remove(Object name) {
	return map.remove(name);
    }

    /**
     * Returns true if this Map maps one or more attribute names (keys)
     * to the specified value.
     *
     * @param value the attribute value
     * @return true if this Map maps one or more attribute names to
     *         the specified value
     */
    public boolean containsValue(Object value) {
	return map.containsValue(value);
    }

    /**
     * Returns true if this Map contains the specified attribute name (key).
     *
     * @param name the attribute name
     * @return true if this Map contains the specified attribute name
     */
    public boolean containsKey(Object name) {
	return map.containsKey(name);
    }

    /**
     * Copies all of the attribute name-value mappings from the specified
     * Attributes to this Map. Duplicate mappings will be replaced.
     *
     * @param attr the Attributes to be stored in this map
     * @exception ClassCastException if attr is not an Attributes
     */
    public void putAll(Map attr) {
	map.putAll((Attributes)attr);
    }

    /**
     * Removes all attributes from this Map.
     */
    public void clear() {
	map.clear();
    }

    /**
     * Returns the number of attributes in this Map.
     */
    public int size() {
	return map.size();
    }

    /**
     * Returns true if this Map contains no attributes.
     */
    public boolean isEmpty() {
	return map.isEmpty();
    }

    /**
     * Returns a Set view of the attribute names (keys) contained in this Map.
     */
    public Set keySet() {
	return map.keySet();
    }

    /**
     * Returns a Collection view of the attribute values contained in this Map.
     */
    public Collection values() {
	return map.values();
    }

    /**
     * Returns a Collection view of the attribute name-value mappings
     * contained in this Map.
     */
    public Set entrySet() {
	return map.entrySet();
    }

    /**
     * Compares the specified Attributes object with this Map for equality.
     * Returns true if the given object is also an instance of Attributes
     * and the two Attributes objects represent the same mappings.
     *
     * @param o the Object to be compared
     * @return true if the specified Object is equal to this Map
     */
    public boolean equals(Object o) {
	return map.equals(o);
    }

    /**
     * Returns the hash code value for this Map.
     */
    public int hashCode() {
	return map.hashCode();
    }

    /**
     * Returns a copy of the Attributes, implemented as follows:
     * <pre>
     *     public Object clone() { return new Attributes(this); }
     * </pre>
     * Since the attribute names and values are themselves immutable,
     * the Attributes returned can be safely modified without affecting
     * the original.
     */
    public Object clone() {
	return new Attributes(this);
    }

    /*
     * Writes the current attributes to the specified data output stream.
     * XXX Need to handle UTF8 values and break up lines longer than 72 bytes
     */
     void write(DataOutputStream os) throws IOException {
	Iterator it = entrySet().iterator();
	while (it.hasNext()) {
	    Map.Entry e = (Map.Entry)it.next();
            StringBuffer buffer = new StringBuffer(
                                        ((Name)e.getKey()).toString());
	    buffer.append(": ");

            String value = (String)e.getValue();
            if (value != null) {
                byte[] vb = value.getBytes("UTF8");
                value = new String(vb, 0, 0, vb.length);
            }
            buffer.append(value);

	    buffer.append("\r\n");
            Manifest.make72Safe(buffer);
            os.writeBytes(buffer.toString());
	}
	os.writeBytes("\r\n");
    }

    /*
     * Writes the current attributes to the specified data output stream,
     * make sure to write out the MANIFEST_VERSION or SIGNATURE_VERSION
     * attributes first.
     *
     * XXX Need to handle UTF8 values and break up lines longer than 72 bytes
     */
    void writeMain(DataOutputStream out) throws IOException 
    {
	// write out the *-Version header first, if it exists
	String vername = Name.MANIFEST_VERSION.toString();
	String version = getValue(vername);
	if (version == null) {
	    vername = Name.SIGNATURE_VERSION.toString();
	    version = getValue(vername);
	}

	if (version != null) {
	    out.writeBytes(vername+": "+version+"\r\n");
	}